Andy asks:

I recently had to have the phone line replaced between the street
and the DeMark box on the side of my house.

It would have been a lot easier for the contractor to have
located
a new DeMark box on the side of the house and taken away the
old one ---- less tunnelling under driveways, etc.

I was told that the Demark box MUST be installed at the
electrical
service entrance and the ground wire attached to the service entrance
ground rod...

I suggested just putting in another ground rod at the alternate
location instead. I was told this was not allowed --- the Demark box
MUST go at the meter service entrance. Both the phone company
technician and the phone line subcontractor told me this, separately.

So, does anyone here have any expertise on this ? I'd sure like
to
see some discussion about this requirement.


Andy in Eureka, Texas

"Andy" wrote in message
...
Andy asks:

I recently had to have the phone line replaced between the street
and the DeMark box on the side of my house.

It would have been a lot easier for the contractor to have
located
a new DeMark box on the side of the house and taken away the
old one ---- less tunnelling under driveways, etc.

I was told that the Demark box MUST be installed at the
electrical
service entrance and the ground wire attached to the service entrance
ground rod...

I suggested just putting in another ground rod at the alternate
location instead. I was told this was not allowed --- the Demark box
MUST go at the meter service entrance. Both the phone company
technician and the phone line subcontractor told me this, separately.

So, does anyone here have any expertise on this ? I'd sure like
to
see some discussion about this requirement.

do you want to reinvent the wheel too?

Andy,

My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

Dave M.

Andy wrote:

Andy asks:

I recently had to have the phone line replaced between the street
and the DeMark box on the side of my house.

It would have been a lot easier for the contractor to have
located
a new DeMark box on the side of the house and taken away the
old one ---- less tunnelling under driveways, etc.

I was told that the Demark box MUST be installed at the
electrical
service entrance and the ground wire attached to the service entrance
ground rod...

I suggested just putting in another ground rod at the alternate
location instead. I was told this was not allowed --- the Demark box
MUST go at the meter service entrance. Both the phone company
technician and the phone line subcontractor told me this, separately.

So, does anyone here have any expertise on this ? I'd sure like
to
see some discussion about this requirement.


Andy in Eureka, Texas



It's too late now, isn't it?

On Aug 27, 8:26�am, "David L. Martel" wrote:
Andy,

� �My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

Dave M.

ALL GROUNDS MUST BE UNIFIED!! Thats why the want the box by the
service entrance. seperate ground rods can create a different voltage
on grounded things, like during a lightning strike, that can be
dangerous.

thats why phone ground, is unified to main house ground rods, incoming
water line with meter jumper etc, even satellite dsh grounds should be
part of a unified system

"David L. Martel" wrote in message
m...
Andy,

My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

you're screwed!

wrote:
On Aug 27, 8:26?am, "David L. Martel" wrote:
Andy,

? ?My phone box was installed by the phone company, Verizon. It is
not near the electrical service box. It has it's own ground rod.

Dave M.

ALL GROUNDS MUST BE UNIFIED!! Thats why the want the box by the
service entrance. seperate ground rods can create a different voltage
on grounded things, like during a lightning strike, that can be
dangerous.

thats why phone ground, is unified to main house ground rods, incoming
water line with meter jumper etc, even satellite dsh grounds should be
part of a unified system

Satellite dish grounds are for the sole purpose of dissipating static
electricity. There's nothing electrical about them.

That doesn't mean that some officious slug hasn't mandated that they be tied
to the central house ground, but I can't see that it would server any
purpose.

On Wed, 27 Aug 2008 07:55:54 -0400, "Bob" wrote:


"Andy" wrote in message
...
Andy asks:

I recently had to have the phone line replaced between the street
and the DeMark box on the side of my house.

It would have been a lot easier for the contractor to have
located
a new DeMark box on the side of the house and taken away the
old one ---- less tunnelling under driveways, etc.

I was told that the Demark box MUST be installed at the
electrical
service entrance and the ground wire attached to the service entrance
ground rod...

I suggested just putting in another ground rod at the alternate
location instead. I was told this was not allowed --- the Demark box
MUST go at the meter service entrance. Both the phone company
technician and the phone line subcontractor told me this, separately.

So, does anyone here have any expertise on this ? I'd sure like
to
see some discussion about this requirement.


There is potential (no pun intended) to create a ground loop by using
two separate ground rods. Ground is somewhat of a relative term. Soil
composition and moisture content are two of the major elements that
can affect it. Not all earth grounds are equal.

Bob wrote:
"David L. Martel" wrote in message
m...
Andy,

My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

you're screwed!


I used to have a Comcast cable attached
to its own ground rod 30' or so from
the electrical service entrance. There
was a lightening strike on a street
light on
the street behind me. It followed the
power cables to the underground area where
electrical, cable and telephone is for
my house. Because of the 2 different
grounds,
we had lots of damage .... computer,
modem, router, scanner, garage door radio,
X10 stuff, and more. The Comcast guy
and the telephone guy all agreed the
grounding
should all be to a single point, the
electrical entrance. I know this is not
exactly the
same thing, but working for the old Bell
System, we used single point grounds in
telephone offices to prevent lightening
from damaging the switching gear. I should
have seen this, but didn't until it was
too late.

In article
,
Andy wrote:

I was told that the Demark box MUST be installed at the
electrical service entrance and the ground wire attached
to the service entrance ground rod...

That is correct and has been required by code for many years.

Specifically, telco and CATV services must be bonded to the MGN
(Multi-Grounded Neutral) wire of the premise using the SHORTEST length
of wire as is practical.

This provides the best "balanced potential" in grounding. It is said
that such practice lowers the chance that, in a direct lightening
strike, the charge will "leap" from a phone or CATV jack to an
electrical outlet. I have seen that sort of damage. It's impressive.

I suggested just putting in another ground rod at the
alternate location instead. I was told this was not allowed
--- the Demark box MUST go at the meter service entrance.

For the BEST service and the best protection from transient spikes
(surges), you WANT the SNI/D at the electric service entrance.

For the first, hundred years or so, telephone service was brought into a
premise at virtually ANY location. They often used a ground rod (4-ft
galvanized!) instead of a water pipe for bonding.

The proliferation of electronic devices (MUCH more susceptible to surge
damage than the old phones) connected to the network made common bonding
imperative.
--

JR

On Aug 27, 10:26*am, "David L. Martel" wrote:
Andy,

* *My phone box was installed by the phone company, Verizon**. It is not near
the electrical service box. It has it's own ground rod.

Dave M.

**Not Bell standard then!

Am very surprised. The various grounds are normally 'bonded' together.
In our case the power neutral is grounded as it enters the house and
has a ground rod. Also the TV cable service and the telephone
protector are grounded/bonded to the same ground. We have also taken
care to bond our ground to a buried copper wire loop that sits in the
trench above the now abandoned one inch plastic pipe to our unused
well.
Many years ago our neighbour, had a bad leak to ground from his
electrical system. Since our systems were all bonded together we had
no problems; but he had some weird voltages floating around the
grounds in his house until he cleared the problem! It was a buried
entrance to his house that had 'gone bad'.
The soil resistivity here is high; so driving a single ground rod is
often not suitable. Hence most electrical systems now use MGN (Multi
Grounded Neutral). This means that except in the case of certain very
high voltage line guy wires everything that is 'ground' should be
bonded together and grounded. This includes overhead transformer
grounds, telephone and cable TV sheaths, pole line guy wires,
telephone sparklightning protectors etc. etc.

On Aug 27, 11:36*am, Art Todesco wrote:
Bob wrote:
"David L. Martel" wrote in message
om...
Andy,

* My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

you're screwed!

I used to have a Comcast cable attached
to its own ground *rod 30' or so from
the electrical service entrance. *There
was a lightening strike on a street
light *on
the street behind me. *It followed the
power cables to the underground area where
electrical, cable and telephone is for
my house. *Because of the 2 different
grounds,
we had lots of damage .... computer,
modem, router, scanner, garage door radio,
X10 stuff, and more. *The Comcast guy
and the telephone guy all agreed the
grounding
should all be to a single point, the
electrical entrance. *I know this is not
exactly the
same thing, but working for the old Bell
System, we used single point grounds in
telephone offices to prevent lightening
from damaging the switching gear. *I should
have seen this, but didn't until it was
too late.

Right on Art: Spent 40 years (1952 to 1992) in telecomm industry
here.
Grounding is like a few other things you don't need very often .......
but when you do ..... !!!!!
Insurance policy, fire extinguisher, accident help, good neighbour
etc. etc.
Cheers.

Jim Redelfs wrote:
In article
,
Andy wrote:

I was told that the Demark box MUST be installed at the
electrical service entrance and the ground wire attached
to the service entrance ground rod...

That is correct and has been required by code for many years.

Specifically, telco and CATV services must be bonded to the MGN
(Multi-Grounded Neutral) wire of the premise using the SHORTEST length
of wire as is practical.
..
The NEC requires a wire "short as practical" with a max length of 20 ft
from phone/cable entry protectors to the power
grounding-electrode-system. (For 1 and 2 family dwellings, if the wire
has to be over 20 ft it can be longer with a ground rod near the entry
protector.) For phones, even 20 ft can be too long.

Phone people like Jim are likely well aware of this. Cable people,
particularly contractors, are more of a problem.
..

This provides the best "balanced potential" in grounding. It is said
that such practice lowers the chance that, in a direct lightening
strike, the charge will "leap" from a phone or CATV jack to an
electrical outlet. I have seen that sort of damage. It's impressive.
..
Can’t imagine.

With a lot of electronic equipment connected to both power and
phone/cable, you want to minimize the voltage between power and
phone/cable wires. Insurance information suggests the most common damage
to electronic equipment is from high voltages between power and
phone/cable wires. Having a *short* wire from phone/cable entry
protectors to the ground at the power service minimizes the voltage
between power and phone/cable wires. The power service is the magic
point because neutral and ground are bonded at that point.

With a strong surge current to earth the "ground" at the building can
rise thousands of volts above 'absolute' ground. You want the power and
phone and cable grounds to rise together.

Art writes about high voltage between power and signal wires. There is
an illustration of a cable ground wire that is too long starting pdf
page 40 in an excellent IEEE guide on surges:
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf

--
bud--

..

I suggested just putting in another ground rod at the
alternate location instead. I was told this was not allowed
--- the Demark box MUST go at the meter service entrance.

For the BEST service and the best protection from transient spikes
(surges), you WANT the SNI/D at the electric service entrance.

For the first, hundred years or so, telephone service was brought into a
premise at virtually ANY location. They often used a ground rod (4-ft
galvanized!) instead of a water pipe for bonding.

The proliferation of electronic devices (MUCH more susceptible to surge
damage than the old phones) connected to the network made common bonding
imperative.

wrote:
On Wed, 27 Aug 2008 07:55:54 -0400, "Bob" wrote:


"Andy" wrote in message
...

Andy asks:

I recently had to have the phone line replaced between the street
and the DeMark box on the side of my house.

It would have been a lot easier for the contractor to have
located
a new DeMark box on the side of the house and taken away the
old one ---- less tunnelling under driveways, etc.

I was told that the Demark box MUST be installed at the
electrical
service entrance and the ground wire attached to the service entrance
ground rod...

I suggested just putting in another ground rod at the alternate
location instead. I was told this was not allowed --- the Demark box
MUST go at the meter service entrance. Both the phone company
technician and the phone line subcontractor told me this, separately.

So, does anyone here have any expertise on this ? I'd sure like
to
see some discussion about this requirement.


There is potential (no pun intended) to create a ground loop by using
two separate ground rods. Ground is somewhat of a relative term. Soil
composition and moisture content are two of the major elements that
can affect it. Not all earth grounds are equal.

This is reminiscent of times (many years ago) when I was setting up HAWK
missile system batteries in the desert. One of the tasks I assigned to
the logistics NCO was to make sure his folks all urinated on the ground
rods driven in at each pieces of equipment. The systems always worked
if this was done first.

If you do this all earth grounds are whole lot more equal.

"Boden" wrote in message
...
This is reminiscent of times (many years ago) when I was setting up HAWK
missile system batteries in the desert. One of the tasks I assigned to
the logistics NCO was to make sure his folks all urinated on the ground
rods driven in at each pieces of equipment. The systems always worked if
this was done first.

If you do this all earth grounds are whole lot more equal.


is that because being wet made the groung better or was is something in the
urine [salt peter from the mess]?

On Wed, 27 Aug 2008 15:15:24 -0400, "Bob" wrote:


"Boden" wrote in message
...
This is reminiscent of times (many years ago) when I was setting up HAWK
missile system batteries in the desert. One of the tasks I assigned to
the logistics NCO was to make sure his folks all urinated on the ground
rods driven in at each pieces of equipment. The systems always worked if
this was done first.

If you do this all earth grounds are whole lot more equal.


is that because being wet made the groung better or was is something in the
urine [salt peter from the mess]?

Go pee on an electric fence and become enlightened..
--
Mr.E

"HeyBub" wrote in message
m...
wrote:
On Aug 27, 8:26?am, "David L. Martel" wrote:
Andy,

? ?My phone box was installed by the phone company, Verizon. It is
not near the electrical service box. It has it's own ground rod.

Dave M.

ALL GROUNDS MUST BE UNIFIED!! Thats why the want the box by the
service entrance. seperate ground rods can create a different voltage
on grounded things, like during a lightning strike, that can be
dangerous.

thats why phone ground, is unified to main house ground rods, incoming
water line with meter jumper etc, even satellite dsh grounds should be
part of a unified system

Satellite dish grounds are for the sole purpose of dissipating static
electricity. There's nothing electrical about them.

That doesn't mean that some officious slug hasn't mandated that they be
tied to the central house ground, but I can't see that it would server any
purpose.


All grounds must be connected together. While the dish ground is to
dissipate static and such, it still must be connected to the other ground
rods . Lets say it is not. If for some reason the other ground rod comes
loose from the house wiring and there is a short that should go to ground
and it doesn't , and you decide at that time to plug in the dish , you
complete the path to ground and get shocked or worse.
Also if a lightning strike is near the house it is possiable to develope a
big differance of potentional between the two ground.

On Wed, 27 Aug 2008 05:35:39 -0700 (PDT), "
wrote:

On Aug 27, 8:26?am, "David L. Martel" wrote:
Andy,

? ?My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

Dave M.

ALL GROUNDS MUST BE UNIFIED!! Thats why the want the box by the
service entrance. seperate ground rods can create a different voltage
on grounded things, like during a lightning strike, that can be
dangerous

Didn't my Ademco burglar alarm come with instructions to install a
separate ground rod? It's connected to the board and not the power
supply, I think to prevent induced voltages from lightning from
ruining the alarm.

It would have been a lot easier to just hook up to the electrical
ground, but I did what the instructions said.

It's been 25 years but I still have the instructions. I will check
later.

"mm" wrote in message
...
On Wed, 27 Aug 2008 05:35:39 -0700 (PDT), "
wrote:

On Aug 27, 8:26?am, "David L. Martel" wrote:
Andy,

? ?My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

Dave M.

ALL GROUNDS MUST BE UNIFIED!! Thats why the want the box by the
service entrance. seperate ground rods can create a different voltage
on grounded things, like during a lightning strike, that can be
dangerous

Didn't my Ademco burglar alarm come with instructions to install a
separate ground rod? It's connected to the board and not the power
supply, I think to prevent induced voltages from lightning from
ruining the alarm.

It would have been a lot easier to just hook up to the electrical
ground, but I did what the instructions said.

It's been 25 years but I still have the instructions. I will check
later.

Could they have learned anything new since then?

"Bob F" wrote in message
...
Didn't my Ademco burglar alarm come with instructions to install a
separate ground rod? It's connected to the board and not the power
supply, I think to prevent induced voltages from lightning from
ruining the alarm.

It would have been a lot easier to just hook up to the electrical
ground, but I did what the instructions said.

It's been 25 years but I still have the instructions. I will check
later.

Could they have learned anything new since then?


some of us have.

On Wed, 27 Aug 2008 21:38:59 -0700, "Bob F"
wrote:


"mm" wrote in message
.. .
On Wed, 27 Aug 2008 05:35:39 -0700 (PDT), "
wrote:

On Aug 27, 8:26?am, "David L. Martel" wrote:
Andy,

? ?My phone box was installed by the phone company, Verizon. It is not near
the electrical service box. It has it's own ground rod.

Dave M.

ALL GROUNDS MUST BE UNIFIED!! Thats why the want the box by the
service entrance. seperate ground rods can create a different voltage
on grounded things, like during a lightning strike, that can be
dangerous

Didn't my Ademco burglar alarm come with instructions to install a
separate ground rod? It's connected to the board and not the power
supply, I think to prevent induced voltages from lightning from
ruining the alarm.

It would have been a lot easier to just hook up to the electrical
ground, but I did what the instructions said.

It's been 25 years but I still have the instructions. I will check
later.

Could they have learned anything new since then?

Sure, but are you saying that's the reason?

Is the requirement described in this thread that grounds be linked
together something that has arisen since 25 years ago?

On Thu, 28 Aug 2008 21:09:51 -0400, wrote:

On Thu, 28 Aug 2008 13:35:57 -0400, mm
wrote:

Didn't my Ademco burglar alarm come with instructions to install a
separate ground rod? It's connected to the board and not the power
supply, I think to prevent induced voltages from lightning from
ruining the alarm.

It would have been a lot easier to just hook up to the electrical
ground, but I did what the instructions said.

It's been 25 years but I still have the instructions. I will check
later.

Could they have learned anything new since then?

Sure, but are you saying that's the reason?

Is the requirement described in this thread that grounds be linked
together something that has arisen since 25 years ago?


It has been in the code for quite a while but buried out in seldom
read articles (Satellite and cable grounds were in the 800 articles
etc)
Things connected to the phone line were never really important until
people started buying phone equipment with 120v line cords on it
(modems, cordless phone or burglar alarms).
When they rewrote article 250 a couple cycles ago (the grounding
stuff) it got moved there.

Good to know. i'm in the middle of reinstalling my alarm, and I'm
redo the ground. thanks all.

In article ,
mm wrote:

Is the requirement described in this thread that grounds be linked
together something that has arisen since 25 years ago?

Yes.
--

JR

On Aug 29, 7:30�am, Jim Redelfs wrote:
In article ,

�mm wrote:
Is the requirement described in this thread that grounds be linked
together something that has arisen since 25 years ago?

Yes.
--
� � � � � �
JR

the meter jumper and better grounds are important too, added
requirements over the years, its a matter of safety