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Rob Mills
 
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Default Surge protector, roll your own

Been snooping around and notice that the cheap (office depot and etc)
plastic strip (5 recep) surge protectors have only one MOV but the more
expensive ones have one MOV at each receptacle. Looks to me as if you could
use metal recep boxes that would hold two or three receps and place a MOV
across each recep, put a metal cover on it and a short 3 wire 12 gauge cord
and have a much better surge protector to protect sensitive equipment for
not much more than the computer/office stores want for the plastic cased
ones.
I have found MOV's rated at 150 volts and 80 Joules at this web site for
$3.81 each,
http://www.electronicplus.com/conten...=TR&subcat=TS1

Any Thoughts?? RM ~

PS, Think I would put a 15 amp push button circuit breaker on the box



  #2   Report Post  
Pagan
 
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Default

"Rob Mills" wrote in message
news:wmFAe.3820$Zt.3318@okepread05...
Been snooping around and notice that the cheap (office depot and etc)
plastic strip (5 recep) surge protectors have only one MOV but the more
expensive ones have one MOV at each receptacle. Looks to me as if you

could
use metal recep boxes that would hold two or three receps and place a MOV
across each recep, put a metal cover on it and a short 3 wire 12 gauge

cord
and have a much better surge protector to protect sensitive equipment for
not much more than the computer/office stores want for the plastic cased
ones.
I have found MOV's rated at 150 volts and 80 Joules at this web site for
$3.81 each,
http://www.electronicplus.com/conten...=TR&subcat=TS1

Any Thoughts?? RM ~

PS, Think I would put a 15 amp push button circuit breaker on the box


There have been some seriously heated discussions about surge protectors.
Personally, I feel they are a small part in overall electronics protection,
and aren't much good at much more than providing a bunch of convenient
outlets. Good grounding is an absolute must, with a direct circuit to the
breaker box if possible.

As for the circuit breaker, that will do a fine job in protecting the wires,
but it adds no protection to anything else hooked up to it. Better
protection would be provided by a fuse, fast or slow blow depending on your
equipment. It's more of a hassle, but it'll be a lot faster than a circuit
breaker.

Pagan


  #3   Report Post  
CL (dnoyeB) Gilbert
 
Posts: n/a
Default

Pagan wrote:
"Rob Mills" wrote in message
news:wmFAe.3820$Zt.3318@okepread05...

Been snooping around and notice that the cheap (office depot and etc)
plastic strip (5 recep) surge protectors have only one MOV but the more
expensive ones have one MOV at each receptacle. Looks to me as if you


could

use metal recep boxes that would hold two or three receps and place a MOV
across each recep, put a metal cover on it and a short 3 wire 12 gauge


cord

and have a much better surge protector to protect sensitive equipment for
not much more than the computer/office stores want for the plastic cased
ones.
I have found MOV's rated at 150 volts and 80 Joules at this web site for
$3.81 each,
http://www.electronicplus.com/conten...=TR&subcat=TS1

Any Thoughts?? RM ~

PS, Think I would put a 15 amp push button circuit breaker on the box



There have been some seriously heated discussions about surge protectors.
Personally, I feel they are a small part in overall electronics protection,
and aren't much good at much more than providing a bunch of convenient
outlets. Good grounding is an absolute must, with a direct circuit to the
breaker box if possible.

As for the circuit breaker, that will do a fine job in protecting the wires,
but it adds no protection to anything else hooked up to it. Better
protection would be provided by a fuse, fast or slow blow depending on your
equipment. It's more of a hassle, but it'll be a lot faster than a circuit
breaker.

Pagan



Fuses are circuit breakers are the same type of device for generally the
same purpose. They protect wiring. For protection of equipment and
people you use a different type of device. Thus the CB is of no use.

As for making your own surge protector, go for it. But I hope you know
all the ins and outs and don't put yourself or your family or your
equipment at undue risk.

--
Respectfully,


CL Gilbert
  #4   Report Post  
SQLit
 
Posts: n/a
Default


"Rob Mills" wrote in message
news:wmFAe.3820$Zt.3318@okepread05...
Been snooping around and notice that the cheap (office depot and etc)
plastic strip (5 recep) surge protectors have only one MOV but the more
expensive ones have one MOV at each receptacle. Looks to me as if you

could
use metal recep boxes that would hold two or three receps and place a MOV
across each recep, put a metal cover on it and a short 3 wire 12 gauge

cord
and have a much better surge protector to protect sensitive equipment for
not much more than the computer/office stores want for the plastic cased
ones.
I have found MOV's rated at 150 volts and 80 Joules at this web site for
$3.81 each,
http://www.electronicplus.com/conten...=TR&subcat=TS1

Any Thoughts?? RM ~

PS, Think I would put a 15 amp push button circuit breaker on the box



Your correct. However 80 joules is not a lot of power. My surge strips are
rated for 300. My whole house protector in the panel is rated for 1500 with
a let through of 300. So far the combination has worked to keep everything
safe.

You might want to read this page

http://www.jascoproducts.com/cgi-loc...html?E+scstore

If your serious about surges then read some of the information by Mike Holt.


  #5   Report Post  
Tony Hwang
 
Posts: n/a
Default

SQLit wrote:
"Rob Mills" wrote in message
news:wmFAe.3820$Zt.3318@okepread05...

Been snooping around and notice that the cheap (office depot and etc)
plastic strip (5 recep) surge protectors have only one MOV but the more
expensive ones have one MOV at each receptacle. Looks to me as if you


could

use metal recep boxes that would hold two or three receps and place a MOV
across each recep, put a metal cover on it and a short 3 wire 12 gauge


cord

and have a much better surge protector to protect sensitive equipment for
not much more than the computer/office stores want for the plastic cased
ones.
I have found MOV's rated at 150 volts and 80 Joules at this web site for
$3.81 each,
http://www.electronicplus.com/conten...=TR&subcat=TS1

Any Thoughts?? RM ~

PS, Think I would put a 15 amp push button circuit breaker on the box




Your correct. However 80 joules is not a lot of power. My surge strips are
rated for 300. My whole house protector in the panel is rated for 1500 with
a let through of 300. So far the combination has worked to keep everything
safe.

You might want to read this page

http://www.jascoproducts.com/cgi-loc...html?E+scstore

If your serious about surges then read some of the information by Mike Holt.


Hi,
Joule is not a measurement of power it is unit of energy.
Let me put it this way, if you get a direct hit nothing uch will work.
Telling from real world experience.
And real protector for whole house costs a lot. And surge current is
much faster than breaker or fuse.
Tony


  #6   Report Post  
Bob S.
 
Posts: n/a
Default



Rob Mills wrote:

Been snooping around and notice that the cheap (office depot and etc)
plastic strip (5 recep) surge protectors have only one MOV but the more
expensive ones have one MOV at each receptacle. Looks to me as if you could
use metal recep boxes that would hold two or three receps and place a MOV
across each recep, put a metal cover on it and a short 3 wire 12 gauge cord
and have a much better surge protector to protect sensitive equipment for
not much more than the computer/office stores want for the plastic cased
ones.


What's wrong with pulling the wall receptacle and placing a MOV across
the hot/ground terminals? Gets rid of the ugly box, protects anything
plugged into it plus down-stream receptacles. Of course you'd have to
remember where it was in case it ever shorted.

Bob S.

  #7   Report Post  
Rob Mills
 
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Default


"Bob S." wrote in message
oups.com...

What's wrong with pulling the wall receptacle and placing a MOV across
the hot/ground terminals?


I guess in theory it should work but after seeing one office depot strip
surge protector burn a spot in my carpet I don't think I would want one
inside my wall. My whole idea was to more or less build a better mouse trap
for the money. One that was huskier and retained the heat better than the
plastic cased ones sold at office and computer supply stores. I also needed
more receps than a single wall recep as I have a several (none that draw a
lot of power) sensitive radios, two computers and a printer. RM~


  #8   Report Post  
w_tom
 
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Default

You are assuming the MOV is the protection. How? What will
that MOV do? Absorb the surge? Block it? Since that MOV is
so far from earth ground, AND because it is so close to
transistors, then it provides the same ineffective protection
provided by power strips.

Furthermore, if those $0.10 parts were so effective, then
they are already inside the appliance. Anything that is
effective on an appliance power cord is already inside the
electronics.

How do effectively protected sites do it? Let's take a
telephone Central Office computer - connected to overhead
wires everywhere in town. They put the connector directly on
earth ground AND up to 50 meters distant from the computer.

No earth ground means no effective protection. Those MOVs
inside a plug-in box or inside the wall receptacle are not
effective.

Don't get mesmerized thinking the MOVs are protection.
Protection can be installed with a copper wire or it can be
installed with an MOV. The MOV only acts like a wire during a
limited time - during the transient. But if wire or MOV does
not make that 'less than 10 foot' connection to earth, then no
effective protection. Protection is the earth ground. MOVs
is only to connect a surge to earth ground. No earth ground?
Then no effective protection no matter how many joules are
installed.

Rob Mills wrote:
I guess in theory it should work but after seeing one office depot
strip surge protector burn a spot in my carpet I don't think I
would want one inside my wall. My whole idea was to more or less
build a better mouse trap for the money. One that was huskier and
retained the heat better than the plastic cased ones sold at
office and computer supply stores. I also needed more receps than
a single wall recep as I have a several (none that draw a lot o
power) sensitive radios, two computers and a printer. RM~

  #9   Report Post  
w_tom
 
Posts: n/a
Default

Learn by building a protector. Notice what the competition
is doing. First, parts cost on the order of $0.10. So how
many joules did they install? Why so little cost of parts and
yet so such a high price for the protector? Second, minimally
sized 'whole house' protectors cost under $50 for over 1000
joules. You may save money by purchasing a 'whole house'
protector only to remove its MOVs.

Consider safety - UL1449 2nd edition. One trick is to put
inductors in series with the MOVs. Therefore pulse rise time
is not as sharp; MOV less likely to vaporize; more likely to
pass the UL1449 test. (Others assume that the inductor
provides additional electronics protection.) Build it. Its a
great way to learn how protection works. You will not save
money. You will learn.

The 15 amp circuit breaker is required for human safety when
a single plug connects to multiple outlets. If a power strip
(with or without protectors) does not have that 15 amp
breaker, then the strip should be disposed as a human safety
threat.

Rob Mills wrote:
Been snooping around and notice that the cheap (office depot and etc)
plastic strip (5 recep) surge protectors have only one MOV but the
more expensive ones have one MOV at each receptacle. Looks to me as
if you could use metal recep boxes that would hold two or three
receps and place a MOV across each recep, put a metal cover on it
and a short 3 wire 12 gauge cord and have a much better surge
protector to protect sensitive equipment for not much more than the
computer/office stores want for the plastic cased ones.
I have found MOV's rated at 150 volts and 80 Joules at this web site
for $3.81 each,
http://www.electronicplus.com/conten...=TR&subcat=TS1

Any Thoughts?? RM ~

PS, Think I would put a 15 amp push button circuit breaker on the box

  #10   Report Post  
w_tom
 
Posts: n/a
Default

Joules are a measure of energy. But that is all irrelevant
to MOVs. For MOVs, joules defines life expectancy. More
specifically, how fast the MOV will degrade. The manufacturer
defines MOV failure mode: degradation - not vaporization.
Joules is the parameter that defines that life expectancy.

Tony Hwang wrote:
Hi,
Joule is not a measurement of power it is unit of energy.
Let me put it this way, if you get a direct hit nothing uch will
work.
Telling from real world experience.
And real protector for whole house costs a lot. And surge current
is much faster than breaker or fuse.
Tony



  #11   Report Post  
w_tom
 
Posts: n/a
Default

Rather than insult, why not demonstrate how MOVs work? If
having problems doing something constructive, start with some
facts from MOV manufacture datasheets quoted in this 11 July
post:
http://tinyurl.com/dtn5m

MOVs work; which is not to stop, block or absorb surges. That
is why plug-in protectors do nothing effective AND why
appliances don't install MOVs where they cannot be effective -
on the power cord.

"Red Cloud®" wrote:
It might help if you had some clue as to how an MOV works. And
they DO work.

rusty redcloud

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CL (dnoyeB) Gilbert
 
Posts: n/a
Default

w_tom wrote:
Joules are a measure of energy. But that is all irrelevant
to MOVs. For MOVs, joules defines life expectancy. More
specifically, how fast the MOV will degrade. The manufacturer
defines MOV failure mode: degradation - not vaporization.
Joules is the parameter that defines that life expectancy.

Tony Hwang wrote:

Hi,
Joule is not a measurement of power it is unit of energy.
Let me put it this way, if you get a direct hit nothing uch will
work.
Telling from real world experience.
And real protector for whole house costs a lot. And surge current
is much faster than breaker or fuse.
Tony


For the record, Power is energy over an amount of time. Its measured in
Watts which is the same as one Joule per second.

--
Respectfully,


CL Gilbert
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CL (dnoyeB) Gilbert
 
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While I agree that surge protectors are not very effective, its mostly
because they are poor quality devices. You can find a good quality
surge protector. You need to know what size surge you intend to
protect. A device can call itself surge protector if its only
protecting a surge the size of say, the vacuum cleaner motor. Or even less.


w_tom wrote:
You are assuming the MOV is the protection. How? What will
that MOV do? Absorb the surge? Block it? Since that MOV is
so far from earth ground, AND because it is so close to
transistors, then it provides the same ineffective protection
provided by power strips.

Furthermore, if those $0.10 parts were so effective, then
they are already inside the appliance. Anything that is
effective on an appliance power cord is already inside the
electronics.

How do effectively protected sites do it? Let's take a
telephone Central Office computer - connected to overhead
wires everywhere in town. They put the connector directly on
earth ground AND up to 50 meters distant from the computer.


What do you mean here? They use 2 ground lines? There must be a + and
-. One can not be grounded. Please explain what 'connector' is?


No earth ground means no effective protection. Those MOVs
inside a plug-in box or inside the wall receptacle are not
effective.

Don't get mesmerized thinking the MOVs are protection.
Protection can be installed with a copper wire or it can be
installed with an MOV. The MOV only acts like a wire during a
limited time - during the transient. But if wire or MOV does
not make that 'less than 10 foot' connection to earth, then no
effective protection. Protection is the earth ground. MOVs
is only to connect a surge to earth ground. No earth ground?
Then no effective protection no matter how many joules are
installed.


The MOV just needs as good or better path to ground than the device it
is protecting. The distance is irrelevant.


--
Respectfully,


CL Gilbert
  #14   Report Post  
CL (dnoyeB) Gilbert
 
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Default

w_tom wrote:
Learn by building a protector. Notice what the competition
is doing. First, parts cost on the order of $0.10. So how
many joules did they install? Why so little cost of parts and
yet so such a high price for the protector? Second, minimally
sized 'whole house' protectors cost under $50 for over 1000
joules. You may save money by purchasing a 'whole house'
protector only to remove its MOVs.

Consider safety - UL1449 2nd edition. One trick is to put
inductors in series with the MOVs. Therefore pulse rise time
is not as sharp; MOV less likely to vaporize; more likely to
pass the UL1449 test. (Others assume that the inductor
provides additional electronics protection.) Build it. Its a
great way to learn how protection works. You will not save
money. You will learn.

The 15 amp circuit breaker is required for human safety when
a single plug connects to multiple outlets. If a power strip
(with or without protectors) does not have that 15 amp
breaker, then the strip should be disposed as a human safety
threat.


circuit breakers/fuses protect wiring (and by doing so protect from
'thermal incident' so I'm not disagreeing with you)
GFCI protect humans
Surge protectors/noise surpressors/filters/etc. protect devices


--
Respectfully,


CL Gilbert
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w_tom
 
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Default

One of those transistorized device that requires protection
is the GFCI. What protects a GFCI? Just another reason for a
'whole house' protector.

"CL (dnoyeB) Gilbert" wrote:
circuit breakers/fuses protect wiring (and by doing so protect from
'thermal incident' so I'm not disagreeing with you)
GFCI protect humans
Surge protectors/noise surpressors/filters/etc. protect devices

--
Respectfully,

CL Gilbert

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