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cable grounding / surge

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  • Home Theatre
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Anonymous
April 7, 2004 7:55:06 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

There seems to be some experts in this group on grounding so I thought
I would ask a question.

I have timewarner install digital cable, however, there is now way for
them to run the cable into the house near the power ground.
Supposedly they are supposed ground to power or not come in, but in
this case they just couldn't do it.

So they ran the cable to the other side of the house for entry which
has no ground. The cable in my area is mostly underground (not on
poles).

So my question is what should I do to protect against lightning
strikes or should I do anything at all? Should I drive a grounding
rod into the ground and connect the cable to that before it enters the
house? Should I buy some sort of inline cable protection device (i.e.
a fuse type that would break the connection in case of a strike) to
put on the cable right as it enters the house before it goes to
splitting and other rooms? Should I not do anything at all?

I just don't want all my televisions and other devices to get fried.
I am assuming that anything plugged into the digital cable box could
potentially be damaged should enough energy travel through the coax to
the digital box and then out some of the output connections. I am not
worried about the digital cable box itself (it is owned by the cable
company).

The other issue is most of my audio/video components are plugged into
UPSs, so there could possibly be grounding loop issues.

Any direction would be appreciated from some of the experts in the
group.

More about : cable grounding surge

April 8, 2004 2:06:07 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

"sub" <subqNO@SPAMspeedynet.net> wrote in message
news:q6q8705uu3obv00m4nrdo3mj31p6s79r9a@4ax.com...
> There seems to be some experts in this group on grounding so I thought
> I would ask a question.
>
> I have timewarner install digital cable, however, there is now way for
> them to run the cable into the house near the power ground.
> Supposedly they are supposed ground to power or not come in, but in
> this case they just couldn't do it.
>
> So they ran the cable to the other side of the house for entry which
> has no ground. The cable in my area is mostly underground (not on
> poles).

If the code in your area allows and your cold water piping is all copper and
bonded to the electrical service panel, you could place your ground block
inside and wire it to a cold water pipe.

Otherwise I would sink an 8ft ground rod in the area and run a 10ga copper
wire from coax ground block near the entry to the rod. Now this is
important. If a second round rod is used, it must be bonded to the main
building ground. In copper, a 6ga wire would be required for this and burial
of the bond wire is acceptable if copper.

Pat
Anonymous
April 8, 2004 5:07:48 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

On Wed, 07 Apr 2004 22:06:07 GMT, "Greywolf"
<greywolfin45@*spamisbad*sbcglobal.net> wrote:

>"sub" <subqNO@SPAMspeedynet.net> wrote in message
>news:q6q8705uu3obv00m4nrdo3mj31p6s79r9a@4ax.com...
>> There seems to be some experts in this group on grounding so I thought
>> I would ask a question.
>>
>> I have timewarner install digital cable, however, there is now way for
>> them to run the cable into the house near the power ground.
>> Supposedly they are supposed ground to power or not come in, but in
>> this case they just couldn't do it.
>>
>> So they ran the cable to the other side of the house for entry which
>> has no ground. The cable in my area is mostly underground (not on
>> poles).
>
>If the code in your area allows and your cold water piping is all copper and
>bonded to the electrical service panel, you could place your ground block
>inside and wire it to a cold water pipe.

This is out.

>
>Otherwise I would sink an 8ft ground rod in the area and run a 10ga copper
>wire from coax ground block near the entry to the rod. Now this is
>important. If a second round rod is used, it must be bonded to the main
>building ground. In copper, a 6ga wire would be required for this and burial
>of the bond wire is acceptable if copper.

So this is a problem. The building power ground is on the other side
of the house. Same problem the cable company was running into. They
can't get the cable inside the building easily where power ground is.
However, there is no ground where they can run cable into the
building.

In this case would it be better to not ground the catv coax at all and
maybe put some sort of inline surge/fuse on the cable? Someone did
say that since the cable is buried in my area that helps a little.


>
>Pat
>
Related resources
Anonymous
April 8, 2004 4:12:25 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

"sub" <subqNO@SPAMspeedynet.net> wrote in message
news:q6q8705uu3obv00m4nrdo3mj31p6s79r9a@4ax.com...
> There seems to be some experts in this group on grounding so I thought
> I would ask a question.
>
> I have timewarner install digital cable, however, there is now way for
> them to run the cable into the house near the power ground.
> Supposedly they are supposed ground to power or not come in, but in
> this case they just couldn't do it.
>
> So they ran the cable to the other side of the house for entry which
> has no ground. The cable in my area is mostly underground (not on
> poles).
>
> So my question is what should I do to protect against lightning
> strikes or should I do anything at all? Should I drive a grounding
> rod into the ground and connect the cable to that before it enters the
> house? Should I buy some sort of inline cable protection device (i.e.
> a fuse type that would break the connection in case of a strike) to
> put on the cable right as it enters the house before it goes to
> splitting and other rooms? Should I not do anything at all?
>
> I just don't want all my televisions and other devices to get fried.
> I am assuming that anything plugged into the digital cable box could
> potentially be damaged should enough energy travel through the coax to
> the digital box and then out some of the output connections. I am not
> worried about the digital cable box itself (it is owned by the cable
> company).
>
> The other issue is most of my audio/video components are plugged into
> UPSs, so there could possibly be grounding loop issues.
>
> Any direction would be appreciated from some of the experts in the
> group.

Simple really. The cable installer needs to do it right. The NEC is very
specific that class 2 wiring must be grounded at the entry point. The need
to bring it in as close to the electrical service ground as possible, ground
it there, then run the cable around the house to where you need it. It may
take more cable, it may be inconvenient, and it may be unsightly, but it is
the only correct way to do it.

Leonard
Anonymous
April 8, 2004 4:27:46 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

To not ground the incoming cable is even a violation of
National Electrical Code. That NEC requirement should be that
well known to anyone answering this question. Incoming cable
must be grounded. Which kind of ground? Not just earth
ground - for lightning protection. Also grounded to breaker
box for human protection. Furthermore, water pipe for
grounding is no longer acceptable. Grounding to a water pipe,
to dump electricity into that water pipe, is a human safety
threat.

Incoming cable must connect to a common, service entrance
ground. Three figures of how houses might be earthed - wrong
(bad) and right - offered as solutions:
http://www.cinergy.com/surge/ttip08.htm

More background-
http://echostar.swiki.net/87
> Note: grounding your switch or ground block to a place other
> than the ground rod where your electrical service enters the
> structure may result in ground loops and/or the danger of shock
> from stray electrical currents.
http://echostar.swiki.net/112
> Contrary to popular opinion, not all earth grounds are at the
> same potential. Either the electrical service ground, the
> telephone ground, or a connection to a cold water pipe may be
> adequate to shunt dangerous currents and voltages from nearby
> lightning strikes to earth, but there can be hundreds of ohms
> of earth resistance between the two ground points.

Run the CATV outside and around house to service entrance.
Run grounding wire underground so that both grounds share a
same, dedicated ground wire that also meets requirements in
code. Both are acceptable solutions. I realize the solution
may be difficult for the installer. But requirements are
quite specific. Grounds must be connected together. This has
long been known and could easily have been done when
construction was underway. Unfortunately the building
industry just never understood the need which is why
corrections now get expensive.

Should ground be an internal wire run through house, then
that ground wire must be routed well away from any and all
other wires. That ground wire bundled with any other internal
wires would create induced surges. Just another reason why
the interconnecting ground wire should be buried outside the
house.

sub wrote:
> ...
> So this is a problem. The building power ground is on the other side
> of the house. Same problem the cable company was running into. They
> can't get the cable inside the building easily where power ground is.
> However, there is no ground where they can run cable into the
> building.
>
> In this case would it be better to not ground the catv coax at all and
> maybe put some sort of inline surge/fuse on the cable? Someone did
> say that since the cable is buried in my area that helps a little.
April 8, 2004 4:33:07 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

"sub" <subqNO@SPAMspeedynet.net> wrote in message
news:1sq970p0kqfqlchth4eas75jqvdk8k0hq1@4ax.com...
> On Wed, 07 Apr 2004 22:06:07 GMT, "Greywolf"
> <greywolfin45@*spamisbad*sbcglobal.net> wrote:
>
> >"sub" <subqNO@SPAMspeedynet.net> wrote in message
> >news:q6q8705uu3obv00m4nrdo3mj31p6s79r9a@4ax.com...
> >> There seems to be some experts in this group on grounding so I thought
> >> I would ask a question.
> >>
> >> I have timewarner install digital cable, however, there is now way for
> >> them to run the cable into the house near the power ground.
> >> Supposedly they are supposed ground to power or not come in, but in
> >> this case they just couldn't do it.
> >>
> >> So they ran the cable to the other side of the house for entry which
> >> has no ground. The cable in my area is mostly underground (not on
> >> poles).
> >
> >If the code in your area allows and your cold water piping is all copper
and
> >bonded to the electrical service panel, you could place your ground block
> >inside and wire it to a cold water pipe.
>
> This is out.
>
> >
> >Otherwise I would sink an 8ft ground rod in the area and run a 10ga
copper
> >wire from coax ground block near the entry to the rod. Now this is
> >important. If a second round rod is used, it must be bonded to the main
> >building ground. In copper, a 6ga wire would be required for this and
burial
> >of the bond wire is acceptable if copper.
>
> So this is a problem. The building power ground is on the other side
> of the house. Same problem the cable company was running into. They
> can't get the cable inside the building easily where power ground is.
> However, there is no ground where they can run cable into the
> building.
>
> In this case would it be better to not ground the catv coax at all and
> maybe put some sort of inline surge/fuse on the cable? Someone did
> say that since the cable is buried in my area that helps a little.
>
You could put an isolation transformer on the cable to prevent a ground loop
from causing audio or visual hum but only grounding will meet building code
and safety issues. Sink an 8ft copper ground rod at the entry and bond it to
the main building ground by running a 6ga copper wire around or through the
house. It's not that hard, it is important, and is a national building code
requirement. Check with your local building department for the code
requirements in your area though. They might require the cable company to do
the work or will know if the underground delivery is protected in such a way
as to meet code requirements without an entry ground. What you don't want is
a nearby lightning strike to set fire to your equipment and possibly burn
the house down. The worst case scenario could have the fire inspector
determine a code violation caused the fire and limit your insurance
company's liability.

Pat
Anonymous
April 9, 2004 6:20:12 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

Excellent diagram, thanks.

Currently, the cable is laying over the yard and the cement driveway
but it is grounded to the service/power ground.

I suppose I need to get with the cable company and find out how they
plan on solving the ground/cable issue. I personally don't want to
drive the ground rod in and have to run the ground cable to the other
side of the house.

On Thu, 08 Apr 2004 12:27:46 -0400, w_tom <w_tom1@hotmail.com> wrote:

> To not ground the incoming cable is even a violation of
>National Electrical Code. That NEC requirement should be that
>well known to anyone answering this question. Incoming cable
>must be grounded. Which kind of ground? Not just earth
>ground - for lightning protection. Also grounded to breaker
>box for human protection. Furthermore, water pipe for
>grounding is no longer acceptable. Grounding to a water pipe,
>to dump electricity into that water pipe, is a human safety
>threat.
>
> Incoming cable must connect to a common, service entrance
>ground. Three figures of how houses might be earthed - wrong
>(bad) and right - offered as solutions:
>http://www.cinergy.com/surge/ttip08.htm
>
>More background-
> http://echostar.swiki.net/87
>> Note: grounding your switch or ground block to a place other
>> than the ground rod where your electrical service enters the
>> structure may result in ground loops and/or the danger of shock
>> from stray electrical currents.
> http://echostar.swiki.net/112
>> Contrary to popular opinion, not all earth grounds are at the
>> same potential. Either the electrical service ground, the
>> telephone ground, or a connection to a cold water pipe may be
>> adequate to shunt dangerous currents and voltages from nearby
>> lightning strikes to earth, but there can be hundreds of ohms
>> of earth resistance between the two ground points.
>
> Run the CATV outside and around house to service entrance.
>Run grounding wire underground so that both grounds share a
>same, dedicated ground wire that also meets requirements in
>code. Both are acceptable solutions. I realize the solution
>may be difficult for the installer. But requirements are
>quite specific. Grounds must be connected together. This has
>long been known and could easily have been done when
>construction was underway. Unfortunately the building
>industry just never understood the need which is why
>corrections now get expensive.
>
> Should ground be an internal wire run through house, then
>that ground wire must be routed well away from any and all
>other wires. That ground wire bundled with any other internal
>wires would create induced surges. Just another reason why
>the interconnecting ground wire should be buried outside the
>house.
>
>sub wrote:
>> ...
>> So this is a problem. The building power ground is on the other side
>> of the house. Same problem the cable company was running into. They
>> can't get the cable inside the building easily where power ground is.
>> However, there is no ground where they can run cable into the
>> building.
>>
>> In this case would it be better to not ground the catv coax at all and
>> maybe put some sort of inline surge/fuse on the cable? Someone did
>> say that since the cable is buried in my area that helps a little.
January 29, 2009 12:57:24 AM

Hi,

Hate to bring an old thread back up, but this is exactly what I need some help on.

I just had cable interent and phone installed this week and have a question about cable routing grounding.

The installer tapped into a box in my front yard ( I assume it is a service access since all the lines are underground). Then laid a cable on top of the ground (temporary due to winter i'm told) over to a box on the side of the house that has the electric meter in it. He connected the cable from the sevice box to a junction that has one outlet and a ground wire that is clamped to the box with the meter.

Up to this point, I am satisfied with the install, but the cable that comes out of the junction has to go to the back of the house to get to where I have my computer set up. I assumed that they could bring the cable into the basement at this point (by drilling in the sill plate) and string it over to the floor in my office, but instead they laid the cable on the ground outside and drilled right through the exterior wall.

I looked in the basement, and it would not require that any floor joists be drilled into, as it would be parallel to them. There is only 20ft of drywall ceiling of the 120 ft it would travel and are no obstructions between the joists over this drywall.

Is it ok for me to just bring the cable after the grounding junction into the basement and string it up my self? I really dont want them trying to bury the cable under my brand new deck and brick patio
!