This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

On 10/5/2012 12:32 PM, Doug wrote:
This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.


The power company around here will install one on your electric meter
base. I'm not sure of a monthly charge or protection guarantee but you
may check if your local power company has such a program. ^_^

TDD

On 10/5/2012 1:32 PM, Doug wrote:
This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.


I prefer to protect individual circuits that have electronic devices
such as computers and TV's. I heard a neighbor had a whole house unit
and when it blew, it took an electrician and half a day to get power back.

On Oct 5, 2:09*pm, Frank wrote:
On 10/5/2012 1:32 PM, Doug wrote:

This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? * Can I just go by the amperage in the circuit
panel (main circuit breaker) ? * * One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. * Suggestions
welcome.

I prefer to protect individual circuits that have electronic devices
such as computers and TV's. *I heard a neighbor had a whole house unit
and when it blew, it took an electrician and half a day to get power back..

If it took an electrician and half a day to get power back,
what do you think would have happened if they instead
relied on plug-in surge protectors for just the TV? A surge
of that magnitude could have wrecked all kinds of stuff
in the house, even that protected by plug-in type.
If it took out a properly installed whole house surge
protecter, then it must have been one hell of a surge,
eg some kind of very close lightning strike.

A whole house surge protector is the first line of
defense against destructive surges, protects everything
in the house, and deals with the surge when it first
enters the house. As recommended by the IEEE,
a tiered protections strategy works best, which
means having sensitive electronics, particularly
those that are connected not only to power but also
to cable, phone lines, etc, protected by additonal
plug-in type protectors. The whole house protector
will deal with any huge surge that comes in via
the power line. The plug-ins will limit the voltage
differential between power and cable, phone, etc.

Eaton is a reputable major manufacturer of electrical
eqpt. Intermatic is another I would recommend. I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. It should take an hour
to install, assuming everything else is in order.

On Fri, 5 Oct 2012 11:42:49 -0700 (PDT), "
wrote:

On Oct 5, 2:09*pm, Frank wrote:
On 10/5/2012 1:32 PM, Doug wrote:

This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? * Can I just go by the amperage in the circuit
panel (main circuit breaker) ? * * One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. * Suggestions
welcome.

I prefer to protect individual circuits that have electronic devices
such as computers and TV's. *I heard a neighbor had a whole house unit
and when it blew, it took an electrician and half a day to get power back.

If it took an electrician and half a day to get power back,
what do you think would have happened if they instead
relied on plug-in surge protectors for just the TV? A surge
of that magnitude could have wrecked all kinds of stuff
in the house, even that protected by plug-in type.
If it took out a properly installed whole house surge
protecter, then it must have been one hell of a surge,
eg some kind of very close lightning strike.

A whole house surge protector is the first line of
defense against destructive surges, protects everything
in the house, and deals with the surge when it first
enters the house. As recommended by the IEEE,
a tiered protections strategy works best, which
means having sensitive electronics, particularly
those that are connected not only to power but also
to cable, phone lines, etc, protected by additonal
plug-in type protectors. The whole house protector
will deal with any huge surge that comes in via
the power line. The plug-ins will limit the voltage
differential between power and cable, phone, etc.

Eaton is a reputable major manufacturer of electrical
eqpt. Intermatic is another I would recommend. I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. It should take an hour
to install, assuming everything else is in order.


I appreciate this help. Since I'm stupid on this subject so this will
help me. Feel free to add to it but thanks again.

wrote:

Eaton is a reputable major manufacturer of electrical
eqpt. Intermatic is another I would recommend. I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. It should take an hour
to install, assuming everything else is in order.

There are a number on Amazon for under $100. You do not need an additional
circuit breaker (usually).

They are dirt-simple to install. If your hand fits a screwdriver, you should
be good to go, assuming you have or can borrow a screwdriver.

I have one on each of my two electrical panels. They cost $55 & $75. I got
one at Home Depot and forgot where I got the other.

On Oct 5, 4:58*pm, "HeyBub" wrote:
wrote:
Eaton is a reputable major manufacturer of electrical
eqpt. * Intermatic is another I would recommend. *I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. *You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. *It should take an hour
to install, assuming everything else is in order.

There are a number on Amazon for under $100. You do not need an additional
circuit breaker (usually).

How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.





They are dirt-simple to install. If your hand fits a screwdriver, you should
be good to go, assuming you have or can borrow a screwdriver.

I have one on each of my two electrical panels. They cost $55 & $75. I got
one at Home Depot and forgot where I got the other.

Doug wrote:
This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

There is a lot of confusing information regarding these. There are very
expensive models that don't have the capability of cheaper units. Some are
listed as to be used at the equipment instead of the box. Some or most hast
stranded leads make sure your breaker, if a attached, can handle stranded
wire. The units I use as can be seen on some Holmes on Holmes. I had a
previous model attached in my box. One day the during a storm the lights
were going off on dim, etc, bang I heard downstairs at the box. Breaker
tripped, unit blew out through it's mounting hole.
Trying to get free replacement, for some reason didn't qualify. I order new
unit, which had upgrade rating to 150000 amps. Good to go.

http://www.drillspot.com/products/13...urge_Protector

Greg

gregz wrote:
Doug wrote:
This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

There is a lot of confusing information regarding these. There are very
expensive models that don't have the capability of cheaper units. Some are
listed as to be used at the equipment instead of the box. Some or most hast
stranded leads make sure your breaker, if a attached, can handle stranded
wire. The units I use as can be seen on some Holmes on Holmes. I had a
previous model attached in my box. One day the during a storm the lights
were going off on dim, etc, bang I heard downstairs at the box. Breaker
tripped, unit blew out through it's mounting hole.
Trying to get free replacement, for some reason didn't qualify. I order new
unit, which had upgrade rating to 150000 amps. Good to go.

http://www.drillspot.com/products/13...urge_Protector

Greg

If you order this, it will come from Grainger, which at granger costs
more.!!

Greg

gregz wrote:
Doug wrote:
This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

There is a lot of confusing information regarding these. There are very
expensive models that don't have the capability of cheaper units. Some are
listed as to be used at the equipment instead of the box. Some or most hast
stranded leads make sure your breaker, if a attached, can handle stranded
wire. The units I use as can be seen on some Holmes on Holmes. I had a
previous model attached in my box. One day the during a storm the lights
were going off on dim, etc, bang I heard downstairs at the box. Breaker
tripped, unit blew out through it's mounting hole.
Trying to get free replacement, for some reason didn't qualify. I order new
unit, which had upgrade rating to 150000 amps. Good to go.

http://www.drillspot.com/products/13...urge_Protector

Greg

I did not have a near lightning strike during this episode. I imagine the
spike came from somewhere. It might even originated from my equipment at
home, if that's possible, or some other house or factory. I had a strike
this summer 100 foot from house. Nothing I could see in house that had any
effect.

Greg

On Fri, 5 Oct 2012 16:02:10 -0500, "HeyBub"
wrote:




They are dirt-simple to install. If your hand fits a screwdriver, you should
be good to go, assuming you have or can borrow a screwdriver.


But how do we know what type of screw driver? There are the tapered
ones that can be used as a chisel and digger, and there are the cute
cross ones for chopping ice.



I have one on each of my two electrical panels. They cost $55 & $75. I got
one at Home Depot and forgot where I got the other.


Most are in the $200 range. How do they differ from the lower priced
ones? Or don't they, aside from price.

On Fri, 5 Oct 2012 14:12:30 -0700 (PDT), "
wrote:




How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.


You can wire them to the same lugs that hold the main wires coming in,
or you can get a lug kit that is used when you add a secondary box.

Ed Pawlowski wrote:
On Fri, 5 Oct 2012 16:02:10 -0500, "HeyBub"
wrote:




They are dirt-simple to install. If your hand fits a screwdriver, you should
be good to go, assuming you have or can borrow a screwdriver.


But how do we know what type of screw driver? There are the tapered
ones that can be used as a chisel and digger, and there are the cute
cross ones for chopping ice.



I have one on each of my two electrical panels. They cost $55 & $75. I got
one at Home Depot and forgot where I got the other.


Most are in the $200 range. How do they differ from the lower priced
ones? Or don't they, aside from price.

I bet they are just being conservative, but the ratings are not any better.
One thing I see on mine, the trip voltage is lower than others.

When I moved in, power company said if I wanted to keep the installed meter
suppressor, I would have to pay so much per month. Question is, did they
remove it. Knowing the old owners of the house, I can't believe they would
pay for something like that.

Greg

On 10/5/2012 4:12 PM, wrote:
On Oct 5, 4:58 pm, "HeyBub" wrote:
wrote:
Eaton is a reputable major manufacturer of electrical
eqpt. Intermatic is another I would recommend. I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. It should take an hour
to install, assuming everything else is in order.

There are a number on Amazon for under $100. You do not need an additional
circuit breaker (usually).

How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.


They are dirt-simple to install. If your hand fits a screwdriver, you should
be good to go, assuming you have or can borrow a screwdriver.

I have one on each of my two electrical panels. They cost $55 & $75. I got
one at Home Depot and forgot where I got the other.


There are some surge arresters that snap in like a standard circuit
breaker into a spare 2 pole slot with a ground wire that needs to be
connected to the ground bar. I don't remember the brand but I remember
seeing a cut sheet on it at the electrical supply house one day. O_o

TDD

On Sat, 06 Oct 2012 00:26:42 -0400, wrote:

On Fri, 05 Oct 2012 22:32:07 -0400, Ed Pawlowski wrote:

On Fri, 5 Oct 2012 14:12:30 -0700 (PDT), "
wrote:




How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.


You can wire them to the same lugs that hold the main wires coming in,
or you can get a lug kit that is used when you add a secondary box.

Don't wire these to the main lugs. There won't be anything to stop the
fire if they short.

Wiring diagram here
http://www.smarthome.com/manuals/48390.pdf

This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.


I prefer to protect individual circuits that have electronic devices such
as computers and TV's. I heard a neighbor had a whole house unit and when
it blew, it took an electrician and half a day to get power back.


*The surge suppressor will blow up when it is not properly grounded. It is
designed to absorb the surge and then dissipate it to ground. With no
ground it just overloads, but still provides some surge protection though it
is only once. Proper surge protection begins with good grounding.

Siemens has a comprehensive online training manual that explains the process
in simple terms and also shows their products. Here's an excerpt: "The
clamping voltage rating of an MOV is greater than the normal supply voltage.
Therefore, when a surge occurs and the clamping voltage rating of the MOV is
exceeded, the MOV switches from a high resistance path to a low resistance
path and excess energy passes through the MOV to ground, bypassing the
connected load".

You can read the whole instructional manual he
http://www.mrelectrician.tv/surgeprotectionbasics.html

On Oct 5, 10:32*pm, Ed Pawlowski wrote:
On Fri, 5 Oct 2012 14:12:30 -0700 (PDT), "

wrote:

How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.

You can wire them to the same lugs that hold the main wires coming in,
or you can get a lug kit that is used when you add a secondary box.

Interesting, I didn't know that connectors like the ILSCO KUPLER IPC
4/0-#6
that taps into the service conductors existed or were allowed. Some
questions:

I've never used a lug kit. I take it that goes on the panel some
place that
does not take up a breaker slot and is typically used to then feed a
subpanel? So, in this case they use it to feed the SS.

If you use the Kupler approach and tap the service conductors
before the main breaker, you then have the SS connected
directly without any breaker. The instructions say this is OK,
but does it depend on where the SS is physically mounted?
Say I mount it next to the panel, as is frequently done. Then
I have it and the wires running between that Kupler and the SS
with no breaker protection, no disconnect, including no main breaker.
Is that allowed? I sure would not do that in my house when
there are other ways to do it.

On Oct 6, 8:14*am, "John Grabowski" wrote:
This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? * Can I just go by the amperage in the circuit
panel (main circuit breaker) ? * * One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. * Suggestions
welcome.

I prefer to protect individual circuits that have electronic devices such
as computers and TV's. *I heard a neighbor had a whole house unit and when
it blew, it took an electrician and half a day to get power back.

*The surge suppressor will blow up when it is not properly grounded. *It is
designed to absorb the surge and then dissipate it to ground.

Just a clarification. The surge protector doesn't absorb
the surge, it just shunts it to ground, assuming it has a
ground. You have that process described below.



With no
ground it just overloads, but still provides some surge protection though it
is only once.

With no ground at all, it would seem all it could do
would be to clamp the various conductors so that
the voltage on any of them relative to the other would
be 600V or so.



Proper surge protection begins with good grounding.

Siemens has a comprehensive online training manual that explains the process
in simple terms and also shows their products. *Here's an excerpt: *"The
clamping voltage rating of an MOV is greater than the normal supply voltage.
Therefore, when a surge occurs and the clamping voltage rating of the MOV is
exceeded, the MOV switches from a high resistance path to a low resistance
path and excess energy passes through the MOV to ground, bypassing the
connected load".

You can read the whole instructional manual hehttp://www.mrelectrician..tv/surgeprotectionbasics.html

On 10/5/2012 2:42 PM, wrote:
On Oct 5, 2:09 pm, Frank wrote:
On 10/5/2012 1:32 PM, Doug wrote:

This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

I prefer to protect individual circuits that have electronic devices
such as computers and TV's. I heard a neighbor had a whole house unit
and when it blew, it took an electrician and half a day to get power back.

If it took an electrician and half a day to get power back,
what do you think would have happened if they instead
relied on plug-in surge protectors for just the TV? A surge
of that magnitude could have wrecked all kinds of stuff
in the house, even that protected by plug-in type.
If it took out a properly installed whole house surge
protecter, then it must have been one hell of a surge,
eg some kind of very close lightning strike.

A whole house surge protector is the first line of
defense against destructive surges, protects everything
in the house, and deals with the surge when it first
enters the house. As recommended by the IEEE,
a tiered protections strategy works best, which
means having sensitive electronics, particularly
those that are connected not only to power but also
to cable, phone lines, etc, protected by additonal
plug-in type protectors. The whole house protector
will deal with any huge surge that comes in via
the power line. The plug-ins will limit the voltage
differential between power and cable, phone, etc.

Eaton is a reputable major manufacturer of electrical
eqpt. Intermatic is another I would recommend. I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. It should take an hour
to install, assuming everything else is in order.


I am speaking as a novice with these minor experiences. My neighbor is
an elderly widow that has to rely on others.

We did have a big surge hit the house where high tension wire was
shorted to house wires. It knocked out all my surge protectors and a
microwave oven that was on a protector that had previously failed. Cost
me about $90 for new protectors as once light is out, they are gone.
Don't know about whole house protector reset or replacement in an
incident like this.

My brother had lightening hit his driveway light pole. Killed
everything in the house. Don't think anything would have protected him.

This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

I prefer to protect individual circuits that have electronic devices
such
as computers and TV's. I heard a neighbor had a whole house unit and
when
it blew, it took an electrician and half a day to get power back.

*The surge suppressor will blow up when it is not properly grounded. It is
designed to absorb the surge and then dissipate it to ground.

Just a clarification. The surge protector doesn't absorb
the surge, it just shunts it to ground, assuming it has a
ground. You have that process described below.


*Thanks for the clarification Trader4. You are correct about the shunting.



With no
ground it just overloads, but still provides some surge protection though
it
is only once.

With no ground at all, it would seem all it could do
would be to clamp the various conductors so that
the voltage on any of them relative to the other would
be 600V or so.


*I'm not sure about that. All I know is that the ones that blow up are
usually the ones with no ground.



Proper surge protection begins with good grounding.

Siemens has a comprehensive online training manual that explains the
process
in simple terms and also shows their products. Here's an excerpt: "The
clamping voltage rating of an MOV is greater than the normal supply
voltage.
Therefore, when a surge occurs and the clamping voltage rating of the MOV
is
exceeded, the MOV switches from a high resistance path to a low resistance
path and excess energy passes through the MOV to ground, bypassing the
connected load".

You can read the whole instructional manual
hehttp://www.mrelectrician.tv/surgeprotectionbasics.html

How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.

You can wire them to the same lugs that hold the main wires coming in,
or you can get a lug kit that is used when you add a secondary box.

Interesting, I didn't know that connectors like the ILSCO KUPLER IPC
4/0-#6
that taps into the service conductors existed or were allowed. Some
questions:

I've never used a lug kit. I take it that goes on the panel some
place that
does not take up a breaker slot and is typically used to then feed a
subpanel? So, in this case they use it to feed the SS.

If you use the Kupler approach and tap the service conductors
before the main breaker, you then have the SS connected
directly without any breaker. The instructions say this is OK,
but does it depend on where the SS is physically mounted?
Say I mount it next to the panel, as is frequently done. Then
I have it and the wires running between that Kupler and the SS
with no breaker protection, no disconnect, including no main breaker.
Is that allowed? I sure would not do that in my house when
there are other ways to do it.


*I agree with Trader4. I don't like having anything connected in a home
that cannot be shut off without pulling the electric meter.

On Oct 6, 8:50*am, "John Grabowski" wrote:
This is after reading and talking to others, I'm thinking about this..
I'm not very educated on electricity so I wonder 2 things right away..
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

I prefer to protect individual circuits that have electronic devices
such
as computers and TV's. I heard a neighbor had a whole house unit and
when
it blew, it took an electrician and half a day to get power back.

*The surge suppressor will blow up when it is not properly grounded. It is
designed to absorb the surge and then dissipate it to ground.

Just a clarification. *The surge protector doesn't absorb
the surge, it just shunts it to ground, assuming it has a
ground. *You have that process described below.

*Thanks for the clarification Trader4. *You are correct about the shunting.

With no

ground it just overloads, but still provides some surge protection though
it
is only once.

With no ground at all, it would seem all it could do
would be to clamp the various conductors so that
the voltage on any of them relative to the other would
be 600V or so.

*I'm not sure about that. *All I know is that the ones that blow up are
usually the ones with no ground.


That's interesting. I take your word for it. It's just that
I'm having a hard time figuring out why that would
happen. With a proper ground almost all the surge
energy passes directly through the surge protector.
Without it, it would seem a lot less energy would pass
through it. Maybe Bud or one of the other guys has
some thoughts.

On 10/5/2012 12:42 PM, wrote:
On Oct 5, 2:09 pm, wrote:

I prefer to protect individual circuits that have electronic devices
such as computers and TV's. I heard a neighbor had a whole house unit
and when it blew, it took an electrician and half a day to get power back.

If it took an electrician and half a day to get power back,
what do you think would have happened if they instead
relied on plug-in surge protectors for just the TV? A surge
of that magnitude could have wrecked all kinds of stuff
in the house, even that protected by plug-in type.
If it took out a properly installed whole house surge
protecter, then it must have been one hell of a surge,
eg some kind of very close lightning strike.

A whole house surge protector is the first line of
defense against destructive surges, protects everything
in the house, and deals with the surge when it first
enters the house. As recommended by the IEEE,
a tiered protections strategy works best, which
means having sensitive electronics, particularly
those that are connected not only to power but also
to cable, phone lines, etc, protected by additonal
plug-in type protectors. The whole house protector
will deal with any huge surge that comes in via
the power line. The plug-ins will limit the voltage
differential between power and cable, phone, etc.

Nice description - I agree with all of it.
I would only add what is implied - for a plug-in protector connect all
interconnected equipment to the same protector and all external wires
(power, phone, cable, ...) go through the protector.


Eaton is a reputable major manufacturer of electrical
eqpt. Intermatic is another I would recommend. I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. It should take an hour
to install, assuming everything else is in order.

And more good information.
Many of the major electrical manufacturers make service panel
protectors. I would buy only a major name brand.

-------------------------
Excellent information on surges and surge protection is at:
http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf

The recommended surge current rating for residential is 20,000 - 70,000A
per service wire. For high lightning areas the recommendation is 40,000
- 120,000A.

An investigation of the possible surge on a residential service used a
100,000A strike to the near utility pole with typical urban overhead
distribution. Only 5% of lightning strikes are stronger, and the strike
is about as close as possible, so this is essentially a worst case. The
surge current was 10,000A per service wire. Higher protector ratings are
not for a single event, but give a long life.

On 10/5/2012 10:41 PM, Ed Pawlowski wrote:
On Sat, 06 Oct 2012 00:26:42 -0400, wrote:

On Fri, 05 Oct 2012 22:32:07 -0400, Ed wrote:

On Fri, 5 Oct 2012 14:12:30 -0700 (PDT), "
wrote:




How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.


You can wire them to the same lugs that hold the main wires coming in,
or you can get a lug kit that is used when you add a secondary box.

Don't wire these to the main lugs. There won't be anything to stop the
fire if they short.

Wiring diagram here
http://www.smarthome.com/manuals/48390.pdf

Most service panel protectors must be connected after the service
breaker. I would rather not connect ahead of that.

---------------------------------
The protectors that a utility will provide (usually lease) connect
between the meter and the meter base.

On 10/6/2012 6:35 AM, Frank wrote:

We did have a big surge hit the house where high tension wire was
shorted to house wires. It knocked out all my surge protectors and a
microwave oven that was on a protector that had previously failed. Cost
me about $90 for new protectors as once light is out, they are gone.
Don't know about whole house protector reset or replacement in an
incident like this.


The protection in almost all surge protectors are MOVs. They can conduct
thousands of amps for the maybe 100 microseconds of a lighting created
surge.

They will be rapidly burned out by the much longer overvoltage of a
crossed power wire (which is not a "surge"). Neither service panel or
plug-in protectors will give reliable protection. UPSs might disconnect
and some plug-in protectors disconnect on overvoltage.

On 10/5/2012 10:38 PM, The Daring Dufas wrote:
On 10/5/2012 4:12 PM, wrote:
On Oct 5, 4:58 pm, "HeyBub" wrote:
wrote:
Eaton is a reputable major manufacturer of electrical
eqpt. Intermatic is another I would recommend. I
would get one rated for at least 20K Amps per phase.
A whole house protector should run $100-150. You
typically need an additional double pole breaker, ~$20,
and as that friend pointed out, if you don't have an empty
slot that will increase the cost. It should take an hour
to install, assuming everything else is in order.

There are a number on Amazon for under $100. You do not need an
additional
circuit breaker (usually).

How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.


They are dirt-simple to install. If your hand fits a screwdriver, you
should
be good to go, assuming you have or can borrow a screwdriver.

I have one on each of my two electrical panels. They cost $55 & $75.
I got
one at Home Depot and forgot where I got the other.


There are some surge arresters that snap in like a standard circuit
breaker into a spare 2 pole slot with a ground wire that needs to be
connected to the ground bar. I don't remember the brand but I remember
seeing a cut sheet on it at the electrical supply house one day. O_o

TDD


Several manufacturers make surge protectors that plug-in like a circuit
breaker - SquareD comes to mind. (They only can be used in panels made
by that manufacturer.)

They can only be used at the service panel, because the neutral and
ground are bonded in the service panel. (At a subpanel the protector
connects to hot-hot-neutral-ground.)

Separate protectors are available with higher surge amp ratings. But the
plug-onto-the-busbar ones are sure convenient.

On 10/6/2012 7:00 AM, wrote:
On Oct 6, 8:50 am, "John wrote:

I prefer to protect individual circuits that have electronic devices
such
as computers and TV's. I heard a neighbor had a whole house unit and
when
it blew, it took an electrician and half a day to get power back.

*The surge suppressor will blow up when it is not properly grounded. It is
designed to absorb the surge and then dissipate it to ground.

Just a clarification. The surge protector doesn't absorb
the surge, it just shunts it to ground, assuming it has a
ground. You have that process described below.

*Thanks for the clarification Trader4. You are correct about the shunting.

With no

ground it just overloads, but still provides some surge protection though
it
is only once.

With no ground at all, it would seem all it could do
would be to clamp the various conductors so that
the voltage on any of them relative to the other would
be 600V or so.

*I'm not sure about that. All I know is that the ones that blow up are
usually the ones with no ground.


That's interesting. I take your word for it. It's just that
I'm having a hard time figuring out why that would
happen. With a proper ground almost all the surge
energy passes directly through the surge protector.
Without it, it would seem a lot less energy would pass
through it. Maybe Bud or one of the other guys has
some thoughts.


IMHO the service panel protector would not have a problem with grounds
that are not as good. Since a lightning surge is a current source, the
current through the protectors might be about the same, but not more.
(But in about all cases there are multiple paths to earth, which would
result in a lower surge current.)

Suppose you threw all your beer bottles in the back yard then built a
metal shack on top of the bottles. Power, telephone and cable come in
adjacent to each other and are all surge-protected to the metal shack.
There is no earth connection. Everything in the shack would be
protected. The power surge protector would work fine and would not blow
up. (You might not want to be entering the shack when a surge hit.)

I agree with trader.

-------------------
Suppose you have a 2,000A surge current to earth and the resistance to
earth is a very good 5 ohms. The "ground" at the house rises to 10,000V
above 'absolute' earth potential. This happens even with very good earthing.

If the earthing is not as good the building "ground" rises to a higher
potential above 'absolute' earth potential.

This can show up at equipment like a pad mounted air conditioning
compressor. The compressor can be at about the potential of the earth
the pad is sitting on. The power wires can be at about the potential of
the building "ground". During the surge they can be thousands of volts
different. A service panel protector does not prevent this. And it can
happen even with good earthing.

John Grabowski wrote:
This is after reading and talking to others, I'm thinking about
this. I'm not very educated on electricity so I wonder 2 things
right away. What brands are good for whole house protection and how
do I know how much protection I need? Can I just go by the
amperage in the circuit panel (main circuit breaker) ? One
person gave me a brand called Eaton and told me depending on model
(Ultra being the best and most expensive) from maybe $250 to $500
but said it could be more if I don't have a spare circuit breaker
to wire into. Suggestions welcome.


I prefer to protect individual circuits that have electronic devices
such as computers and TV's. I heard a neighbor had a whole house
unit and when it blew, it took an electrician and half a day to get
power back.


*The surge suppressor will blow up when it is not properly grounded. It is
designed to absorb the surge and then dissipate it to ground. With no
ground it just overloads, but still provides some surge
protection though it is only once. Proper surge protection begins
with good grounding.
Siemens has a comprehensive online training manual that explains the
process in simple terms and also shows their products. Here's an
excerpt: "The clamping voltage rating of an MOV is greater than the
normal supply voltage. Therefore, when a surge occurs and the
clamping voltage rating of the MOV is exceeded, the MOV switches from
a high resistance path to a low resistance path and excess energy
passes through the MOV to ground, bypassing the connected load".

You can read the whole instructional manual he
http://www.mrelectrician.tv/surgeprotectionbasics.html

Right. In sum, most MOVs (Metallic Oxide Varistor) act like a fuse in
reverse.

And, like a fuse, an MOV only works once (or at best a few times).

The more expensive surge protectors do not use these MOVs but instead rely
on electronic magic to take care of business, then reset, ready for the next
surge.

" wrote:
On Oct 6, 8:50 am, "John Grabowski" wrote:
This is after reading and talking to others, I'm thinking about this.
I'm not very educated on electricity so I wonder 2 things right away.
What brands are good for whole house protection and how do I know how
much protection I need? Can I just go by the amperage in the circuit
panel (main circuit breaker) ? One person gave me a brand called
Eaton and told me depending on model (Ultra being the best and most
expensive) from maybe $250 to $500 but said it could be more if I
don't have a spare circuit breaker to wire into. Suggestions
welcome.

I prefer to protect individual circuits that have electronic devices
such
as computers and TV's. I heard a neighbor had a whole house unit and
when
it blew, it took an electrician and half a day to get power back.

*The surge suppressor will blow up when it is not properly grounded. It is
designed to absorb the surge and then dissipate it to ground.

Just a clarification. The surge protector doesn't absorb
the surge, it just shunts it to ground, assuming it has a
ground. You have that process described below.

*Thanks for the clarification Trader4. You are correct about the shunting.

With no

ground it just overloads, but still provides some surge protection though
it
is only once.

With no ground at all, it would seem all it could do
would be to clamp the various conductors so that
the voltage on any of them relative to the other would
be 600V or so.

*I'm not sure about that. All I know is that the ones that blow up are
usually the ones with no ground.


That's interesting. I take your word for it. It's just that
I'm having a hard time figuring out why that would
happen. With a proper ground almost all the surge
energy passes directly through the surge protector.
Without it, it would seem a lot less energy would pass
through it. Maybe Bud or one of the other guys has
some thoughts.

The devices in the protector do not last once hit. They either reduce
capability or completely fail. One shot, blow up. MOV. Surge protectors or
anything else, are not designed to deal with a direct lightning strike. The
common connection is the same place ground is, unless it goes to a
different ground stake or stakes.

Greg

bud-- wrote:
On 10/5/2012 10:41 PM, Ed Pawlowski wrote:
On Sat, 06 Oct 2012 00:26:42 -0400, wrote:

On Fri, 05 Oct 2012 22:32:07 -0400, Ed wrote:

On Fri, 5 Oct 2012 14:12:30 -0700 (PDT), "
wrote:




How do you install it without an additional circuit breaker?
gfretw indicated that you could do that if an existing breaker has
terminals that are listed for and allow double tapping, but
in my experience that is not a breaker that you typically
find in a home panel.


You can wire them to the same lugs that hold the main wires coming in,
or you can get a lug kit that is used when you add a secondary box.

Don't wire these to the main lugs. There won't be anything to stop the
fire if they short.

Wiring diagram here
http://www.smarthome.com/manuals/48390.pdf

Most service panel protectors must be connected after the service
breaker. I would rather not connect ahead of that.

---------------------------------
The protectors that a utility will provide (usually lease) connect
between the meter and the meter base.

I think that's called secondary protection.

Greg

On 10/6/2012 11:28 AM, gregz wrote:

The devices in the protector do not last once hit. They either reduce
capability or completely fail. One shot, blow up. MOV. Surge protectors or
anything else, are not designed to deal with a direct lightning strike.

That is all complete nonsense.

The
common connection is the same place ground is, unless it goes to a
different ground stake or stakes.


Not obvious what you are saying.

You do not want multiple earthing systems. You create an earthing
system, which may have multiple earthing electrodes, and connect it at
the service to the power system ground, which is bonded to the service
neutral. Entry protectors for phone and cable must connect with short
ground wires to a common connection point on the power earthing system.
Dish entry protectors also connect there.

Multiple earthing electrodes can be at far different potential during a
surge 'event' or a nearby lightning strike. Much of the protection is
that during an 'event' the building wiring may rise far above 'absolute'
earth potential, but they all rises together.

On 10/6/2012 10:37 AM, HeyBub wrote:

Right. In sum, most MOVs (Metallic Oxide Varistor) act like a fuse in
reverse.

And, like a fuse, an MOV only works once (or at best a few times).

Nonsense.

MOVs have an energy (joule) rating. It is the energy the MOV can absorb
in single event - one surge - that puts the MOV at its defined end of
life (but still functional). If the energy hits are much smaller than
the single event rating, the cumulative energy rating is much higher.
For example a MOV might have a (single event) rating of 1,000J. If the
individual hits are 14J the cumulative energy rating might be 13,000J.
With high ratings a MOV may never fail.

That is particularly true for a plug-in protector. For a couple reasons
the energy that can make it to the protector is very limited. An
investigation found the maximum was 35 joules. That was with power
service surges that were up to 10,000A (which, as in another post, is
the maximum that has any reasonable probability of occurring).

Plug-in protectors with high ratings are not likely to fail. That is one
reason why some of them have connected equipment warranties. If wired
correctly they are very likely to protect from very near very strong
lightning strikes.

(Neither plug-in or service panel protectors protect by absorbing a
surge. But in the process of protecting they absorb some energy.)


The more expensive surge protectors do not use these MOVs but instead rely
on electronic magic to take care of business, then reset, ready for the next
surge.


According to the IEEE surge guide, "the vast majority (90%) of both
hard-wired and plug-in protectors use MOVs to perform the
voltage-limiting function. In most AC protectors, they are the only
significant voltage limiters." I don't know of any protection schemes
for service panel protectors that do not use MOVs. They are so
widespread because they have high energy dissipation capacity in a small
package at relatively low cost.

bud-- wrote:
On 10/6/2012 11:28 AM, gregz wrote:

The devices in the protector do not last once hit. They either reduce
capability or completely fail. One shot, blow up. MOV. Surge
protectors or anything else, are not designed to deal with a direct
lightning strike.

That is all complete nonsense.


Please refrain from confusing people with silliness:

"A varistor remains non-conductive as a shunt-mode device during normal
operation when the voltage across it remains well below its "clamping
voltage", so varistors are typically used to suppress line voltage surges.
However, a varistor may not be able to successfully limit a very large surge
from an event such as a lightning strike where the energy involved is many
orders of magnitude greater than it can handle.

"Follow-through current as a result of a strike may generate excessive
current that completely destroys the varistor. Lesser surges still degrade
it, however.

"Degradation is defined by manufacturer's life-expectancy charts that relate
current, time and number of transient pulses. The main parameter affecting
varistor life expectancy is its energy (Joule) rating. As the energy rating
increases, its life expectancy typically increases exponentially, the number
of transient pulses that it can accommodate increases and the "clamping
voltage" it provides during each transient decreases. The probability of
catastrophic failure can be reduced by increasing the rating, either by
using a single varistor of higher rating or by connecting more devices in
parallel. A varistor is typically deemed to be fully degraded when its
"clamping voltage" has changed by 10%. In this condition it is not visibly
damaged and it remains functional (no catastrophic failure)."

http://en.wikipedia.org/wiki/Varistor

What's important is that a MOV may be completely degraded without showing
outward signs. Of course if the MOV is black and partially melted, you have
a clue... but baring that, you just don't know.

And can't really know inasmuch as there's no way to non-destructively test
the thing.

On Oct 7, 4:37*pm, "HeyBub" wrote:
bud-- wrote:
On 10/6/2012 11:28 AM, gregz wrote:

The devices in the protector do not last once hit. They either reduce
capability or completely fail. One shot, blow up. MOV. Surge
protectors or anything else, are not designed to deal with a direct
lightning strike.

That is all complete nonsense.

Please refrain from confusing people with silliness:

"A varistor remains non-conductive as a shunt-mode device during normal
operation when the voltage across it remains well below its "clamping
voltage", so varistors are typically used to suppress line voltage surges..
However, a varistor may not be able to successfully limit a very large surge
from an event such as a lightning strike where the energy involved is many
orders of magnitude greater than it can handle.

I think the issue here is that your statement that
"devices in a protector do not last once hit" is
misleading. It depends on what the rating for the
protector is versus what it is hit by.

Case A: It's a 20K Amp whole house surge protector
and it's hit by a typical surge that might occur from
a lightning strike that occurs somewhere down the
street. In that case the current/energy is going to probably
be two orders of magnitude less than the rating of
the protector. In that case, the surge protector
survives, is still functional and it's capacity has minimal
degradation.

Case B: It's a 20K Aamp protector and it's hit by a
very close strike and it sees 50K amps. In that case
it could either be blown up or as you say, have
significantly reduced capacity.

And the far more common occurence for any
protector is that it will likely see a lot more of the Case A
type surges, because direct or near direct hits
are rare. A direct hit can't even really reach the
surge protector. If it hit the service near where it
enters the house, typically a lot of the energy is
going to go elsewhere, via arcing, leaving only
part of the strike for the surge protector to deal with.





"Follow-through current as a result of a strike may generate excessive
current that completely destroys the varistor. Lesser surges still degrade
it, however.

"Degradation is defined by manufacturer's life-expectancy charts that relate
current, time and number of transient pulses. The main parameter affecting
varistor life expectancy is its energy (Joule) rating. As the energy rating
increases, its life expectancy typically increases exponentially, the number
of transient pulses that it can accommodate increases and the "clamping
voltage" it provides during each transient decreases. The probability of
catastrophic failure can be reduced by increasing the rating, either by
using a single varistor of higher rating or by connecting more devices in
parallel. A varistor is typically deemed to be fully degraded when its
"clamping voltage" has changed by 10%. In this condition it is not visibly
damaged and it remains functional (no catastrophic failure)."

http://en.wikipedia.org/wiki/Varistor

What's important is that a MOV may be completely degraded without showing
outward signs. Of course if the MOV is black and partially melted, you have
a clue... but baring that, you just don't know.

And can't really know inasmuch as there's no way to non-destructively test
the thing.

That does seem to be an inherent problem.

bud-- wrote:
On 10/6/2012 11:28 AM, gregz wrote:

The devices in the protector do not last once hit. They either reduce
capability or completely fail. One shot, blow up. MOV. Surge protectors or
anything else, are not designed to deal with a direct lightning strike.

That is all complete nonsense.

The
common connection is the same place ground is, unless it goes to a
different ground stake or stakes.


Not obvious what you are saying.

You do not want multiple earthing systems. You create an earthing system,
which may have multiple earthing electrodes, and connect it at the
service to the power system ground, which is bonded to the service
neutral. Entry protectors for phone and cable must connect with short
ground wires to a common connection point on the power earthing system.
Dish entry protectors also connect there.

Multiple earthing electrodes can be at far different potential during a
surge 'event' or a nearby lightning strike. Much of the protection is
that during an 'event' the building wiring may rise far above 'absolute'
earth potential, but they all rises together.

I was just thinking about the two or three ground rods near my service
entrance. Not sure if there is a code stating things other than so many
feet deep. I never really thought about it, by my grounds must be poor.
They are close to the foundation, on the dry side of the house, and they
might not even go below foundation, because of the landscape. I got another
ground rod on other side of house off my aluminum porch roof, and iron
railing. I know the light box ground is also connected to the same porch
metals. A strike somewhere might cause significant current right through
house. Another ground rod off elevated deck attached to metal rods in the
air, plus cb antenna.

Separate garage, wired from house. There is no ground rods at garage, and
no boxes. I think there might be a code for a ground, not sure. I have no
box in garage, except for junction boxes. There is a ground rod connected
to sheds metal roof.

Greg

wrote:
On Oct 7, 4:37 pm, "HeyBub" wrote:
bud-- wrote:
On 10/6/2012 11:28 AM, gregz wrote:

The devices in the protector do not last once hit. They either
reduce capability or completely fail. One shot, blow up. MOV. Surge
protectors or anything else, are not designed to deal with a direct
lightning strike.

That is all complete nonsense.

Please refrain from confusing people with silliness:

"A varistor remains non-conductive as a shunt-mode device during
normal operation when the voltage across it remains well below its
"clamping voltage", so varistors are typically used to suppress line
voltage surges. However, a varistor may not be able to successfully
limit a very large surge from an event such as a lightning strike
where the energy involved is many orders of magnitude greater than
it can handle.

I think the issue here is that your statement that
"devices in a protector do not last once hit" is
misleading. It depends on what the rating for the
protector is versus what it is hit by.

Actually I said: "And, like a fuse, an MOV only works once (or at best a few
times)."

On Mon, 8 Oct 2012 07:58:15 -0500, "HeyBub" wrote:

wrote:
On Oct 7, 4:37 pm, "HeyBub" wrote:
bud-- wrote:
On 10/6/2012 11:28 AM, gregz wrote:

The devices in the protector do not last once hit. They either
reduce capability or completely fail. One shot, blow up. MOV. Surge
protectors or anything else, are not designed to deal with a direct
lightning strike.

That is all complete nonsense.

Please refrain from confusing people with silliness:

"A varistor remains non-conductive as a shunt-mode device during
normal operation when the voltage across it remains well below its
"clamping voltage", so varistors are typically used to suppress line
voltage surges. However, a varistor may not be able to successfully
limit a very large surge from an event such as a lightning strike
where the energy involved is many orders of magnitude greater than
it can handle.

I think the issue here is that your statement that
"devices in a protector do not last once hit" is
misleading. It depends on what the rating for the
protector is versus what it is hit by.

Actually I said: "And, like a fuse, an MOV only works once (or at best a few
times)."

It's more like a fuse that increases in ampacity every time it reaches 25% of
its ratings. Perhaps not quite as useless but caution is advised.

On 10/7/2012 4:44 PM, wrote:
On Oct 7, 4:37 pm, wrote:
bud-- wrote:
On 10/6/2012 11:28 AM, gregz wrote:

The devices in the protector do not last once hit. They either reduce
capability or completely fail. One shot, blow up. MOV. Surge
protectors or anything else, are not designed to deal with a direct
lightning strike.

That is all complete nonsense.

Please refrain from confusing people with silliness:

"A varistor remains non-conductive as a shunt-mode device during normal
operation when the voltage across it remains well below its "clamping
voltage", so varistors are typically used to suppress line voltage surges.
However, a varistor may not be able to successfully limit a very large surge
from an event such as a lightning strike where the energy involved is many
orders of magnitude greater than it can handle.

So you use a larger MOV.

I showed why a plug-in protector with high ratings is not likely to fail
right after your (HeyBub's) post.

I show how a service panel protector can survive very strong very near
lightning strikes in another post and below.


I think the issue here is that your statement that
"devices in a protector do not last once hit" is
misleading. It depends on what the rating for the
protector is versus what it is hit by.

Case A: It's a 20K Amp whole house surge protector
and it's hit by a typical surge that might occur from
a lightning strike that occurs somewhere down the
street. In that case the current/energy is going to probably
be two orders of magnitude less than the rating of
the protector. In that case, the surge protector
survives, is still functional and it's capacity has minimal
degradation.

Case B: It's a 20K Aamp protector and it's hit by a
very close strike and it sees 50K amps. In that case
it could either be blown up or as you say, have
significantly reduced capacity.

But you don't get 50kA on the power service to your house.

An investigation, which is described somewhere in this thread, used a
100kA strike to a utility pole adjacent to the house. Only 5% of strikes
are stronger, and the strike was about as close as you can get. It is
the worst case that is likely. The surge current to the house was 10kA
per service wire. 10kA per wire is the worst case with any probability
of occurring. There is a reference to it in the IEEE surge guide.

Your 20kA protector can protect from 2 100kA strikes to the utility
pole adjacent to your house. And that is with the minimum rating that
you and the IEEE recommend.


And the far more common occurence for any
protector is that it will likely see a lot more of the Case A
type surges, because direct or near direct hits
are rare. A direct hit can't even really reach the
surge protector. If it hit the service near where it
enters the house, typically a lot of the energy is
going to go elsewhere, via arcing, leaving only
part of the strike for the surge protector to deal with.

Yes, exactly.
There are multiple paths to earth lightning arestors on the distribution
wire, and earthing at the transformer and other houses.




"Follow-through current as a result of a strike may generate excessive
current that completely destroys the varistor. Lesser surges still degrade
it, however.

Not obvious what this refers to.

You can get follow-on currents in arc-type voltage limiters, where the
surge initiates an arc and the normal voltage can continue the arc
briefly. MOVs are not arc-type limiters.

Failing MOVs start to conduct at lower voltages and eventually conduct
on normal voltage. Then they go into thermal runaway. UL listed
protectors have thermal protectors to disconnect these failing MOVs.

....


What's important is that a MOV may be completely degraded without showing
outward signs. Of course if the MOV is black and partially melted, you have
a clue... but baring that, you just don't know.

And can't really know inasmuch as there's no way to non-destructively test
the thing.

That does seem to be an inherent problem.

Actually you can test them but it is quite impractical.

When MOVs fail UL requires (since 1998) they be disconnected. Decent
protectors will tell you if that happens.

For plug-in protectors the IEEE surge guide explains the protected load
can be connected across the MOVs, and be disconnected with them, or can
be connected across the incoming wires. If connected across the MOVs the
protected load is not exposed if MOVs fail. Connecting this way is one
reason some manufacturers can have protected equipment warranties.
Starting 2005 UL requires manufacturers notify buyers if disconnecting
the MOVs does NOT disconnect the protected equipment.

With high ratings a plug-in protector is not likely to fail anyway (as
covered in a post to Bub).

Also use high ratings for service panel protectors.

On 10/7/2012 7:50 PM, gregz wrote:
wrote:
On 10/6/2012 11:28 AM, gregz wrote:

The
common connection is the same place ground is, unless it goes to a
different ground stake or stakes.


Not obvious what you are saying.

You do not want multiple earthing systems. You create an earthing system,
which may have multiple earthing electrodes, and connect it at the
service to the power system ground, which is bonded to the service
neutral. Entry protectors for phone and cable must connect with short
ground wires to a common connection point on the power earthing system.
Dish entry protectors also connect there.

Multiple earthing electrodes can be at far different potential during a
surge 'event' or a nearby lightning strike. Much of the protection is
that during an 'event' the building wiring may rise far above 'absolute'
earth potential, but they all rises together.

I was just thinking about the two or three ground rods near my service
entrance. Not sure if there is a code stating things other than so many
feet deep. I never really thought about it, by my grounds must be poor.
They are close to the foundation, on the dry side of the house, and they
might not even go below foundation, because of the landscape.

If using a rod the code wants it to be 25 ohms to earth, or you can
install more than one with no resistance requirement. Easiest is to
install 2 or more. I would guess the 3 rods are the power earthing
system. I have occasionally driven a rod through the floor under the
service. It avoids being close to the foundation and may be in moister
soil. Rods are a crappy earthing electrode.

I got another
ground rod on other side of house off my aluminum porch roof, and iron
railing. I know the light box ground is also connected to the same porch
metals. A strike somewhere might cause significant current right through
house. Another ground rod off elevated deck attached to metal rods in the
air, plus cb antenna.

I would guess the rods off your metal roofs are crude lighting
protection. It might prevent a fire at the point of the strike, but does
not prevent major electrical damage.

For a lightning rod system, the earthing system must be bonded to the
power earthing system. With high lightning currents to earth and
resistance to earth plus impedance of down conductors there can be a
very high voltage between down conductors and other metal. Metal within
6 feet of the down conductors may have to be bonded to them. Protection
from a direct strike isn't simple.

The NEC wants metal support parts of an antenna connected to the power
earthing system. And a protector(for coax just a ground block) that is
connected to the power earthing system where the antenna lead enters the
building. This will not protect from a direct lightning hit to the antenna.


Separate garage, wired from house. There is no ground rods at garage, and
no boxes. I think there might be a code for a ground, not sure. I have no
box in garage, except for junction boxes. There is a ground rod connected
to sheds metal roof.

Greg

The code wants a grounding electrode at a detached garage if fed by a
feeder (with panel in garage), but it is not required if there is only a
branch circuit to the garage.

On Sun, 7 Oct 2012 15:44:42 -0700 (PDT), "
wrote:


And the far more common occurence for any
protector is that it will likely see a lot more of the Case A
type surges, because direct or near direct hits
are rare. A direct hit can't even really reach the
surge protector. If it hit the service near where it
enters the house, typically a lot of the energy is
going to go elsewhere, via arcing, leaving only
part of the strike for the surge protector to deal with.


What if your electric service is underground? There are still surges
induced from lighning hitting trees, right? Etc?

My phone service is on poles until 400 or 500 feet from my house,
where it goes underground, but I don't know where the electric does.
,