I have a client with an older house. Both the power and the telephone services (point of connection to the utility) were originally on a pole several hundred feet from the house. Several years ago they had a second phone line installed and the phone company moved their interface box from the pole to the house. The new telephone interface box is not grounded to anything. Since then they have had repeated damage to telephone equipment due to lightning. All the equipment damaged was connected to both the telephone and the power systems. They asked the telephone company to check out the problem and the telephone company agreed that the interface box should be grounded and wants to ground it to the neutral in the main power panel in the house. Is this a good idea? Any other suggestions?
Grounding telephone service entrance
- Thread starter hydrobob
- Start date
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- Location
- Bremerton, Washington
Re: Grounding telephone service entrance
Bennie is correct. The bonding point for all the telecommunications should be at the service grounding point, to minimize the potential difference between the systems in a lighting strike or overvoltage. bonding at different points as it is now, creates a potential, due to voltage drop, when causes a current flow, damaging equipment. Also a TVSS for the house and telecommunications gear should be installed at the service entrance.
Bennie is correct. The bonding point for all the telecommunications should be at the service grounding point, to minimize the potential difference between the systems in a lighting strike or overvoltage. bonding at different points as it is now, creates a potential, due to voltage drop, when causes a current flow, damaging equipment. Also a TVSS for the house and telecommunications gear should be installed at the service entrance.
Re: Grounding telephone service entrance
It is obvious why you have had problems. As already stated the NID needs to be bonded to the service electrode.
Do not bond the NID to a seperate electrode as some Telco's would do as this will only amplify the probelm. If a seperate electrode is selected it must be bonded to the service electrode to be effective.
It is obvious why you have had problems. As already stated the NID needs to be bonded to the service electrode.
Do not bond the NID to a seperate electrode as some Telco's would do as this will only amplify the probelm. If a seperate electrode is selected it must be bonded to the service electrode to be effective.
Re: Grounding telephone service entrance
What do you do when you have a meter on a pole some 60 feet overhead from the house with only a three wire entrance into the house? Telco is on the other side of the house (satellite and aerial are also on another side!). I am suggesting a ground ring but how effective will that be since this house has such a long run of electric service line without any additional grounding (meter pole would be closest ground except the telco separate ground on other side).
What do you do when you have a meter on a pole some 60 feet overhead from the house with only a three wire entrance into the house? Telco is on the other side of the house (satellite and aerial are also on another side!). I am suggesting a ground ring but how effective will that be since this house has such a long run of electric service line without any additional grounding (meter pole would be closest ground except the telco separate ground on other side).
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Grounding telephone service entrance
shlcmid: You have gotten me thinking about the possibility that my own home might have a grounding issue. But I?ll start a new thread, rather than diverting this one.
shlcmid: You have gotten me thinking about the possibility that my own home might have a grounding issue. But I?ll start a new thread, rather than diverting this one.
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: Grounding telephone service entrance
shlcmid,
You could run a 10AWG copper wire from the telco entrance around the outside of your house and connect it to your ground rod.
Dave
shlcmid,
You could run a 10AWG copper wire from the telco entrance around the outside of your house and connect it to your ground rod.
Dave
- Location
- Illinois
- Occupation
- retired electrician
Re: Grounding telephone service entrance
If the distance from the telephone system primary protector is over 20'from the service grounding system, then the exception to 800.40(A)(4) requires a communication system grounding electrode per 800.40(B)(2)(2) and a #6 copper bond from the commnications electrode to the service electrode. Note that this section only applies to one and two family dwelling units.
Don
If the distance from the telephone system primary protector is over 20'from the service grounding system, then the exception to 800.40(A)(4) requires a communication system grounding electrode per 800.40(B)(2)(2) and a #6 copper bond from the commnications electrode to the service electrode. Note that this section only applies to one and two family dwelling units.
Don
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: Grounding telephone service entrance
Good catch Don!
Thanks!
Good catch Don!
Thanks!
brian john
Senior Member
- Location
- Leesburg, VA
Re: Grounding telephone service entrance
Bennie:
I know you have issues with some of the NEC grounding practices and your allowed that's what keeps thing moving. My issue has always been terminology.
Pick 4 licensed electricians and ask them the difference between a GEC and an EGC and the grounded conductor and a neutral conductor. See how many can answer the question, in my expierence few could.
Bennie:
I know you have issues with some of the NEC grounding practices and your allowed that's what keeps thing moving. My issue has always been terminology.
Pick 4 licensed electricians and ask them the difference between a GEC and an EGC and the grounded conductor and a neutral conductor. See how many can answer the question, in my expierence few could.
Re: Grounding telephone service entrance
Brian: I have no problem with GEC and EGC as identification terms.
My problem is the use of words that indicate what a conductor has done, will do, and might do.
Specifically the old "ed" and "ing" use.
Ask fourty electricians, "which one is the ground, grounded, and grounding conductor"? find out how many get it correct.
Actually... find out how many care
[ June 30, 2003, 10:25 AM: Message edited by: bennie ]
Brian: I have no problem with GEC and EGC as identification terms.
My problem is the use of words that indicate what a conductor has done, will do, and might do.
Specifically the old "ed" and "ing" use.
Ask fourty electricians, "which one is the ground, grounded, and grounding conductor"? find out how many get it correct.
Actually... find out how many care
[ June 30, 2003, 10:25 AM: Message edited by: bennie ]
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