Bonding of a Telephone Board. Multi family

[eric64]

I was looking for some clarification on this matter. I interpreted the grounding electrode requirement for the telephone board could be acheived via a #6 cu. bonding conductor. I ran this bonding conductor directly to the grounding electrode system for the building. Is this a proper installation? Also I was curious if I could run this #6 bonding conductor through the same raceway as the telephone cables. You see there is a phone board on the 3rd and 5th floor of this building. Running it in the same raceway seems to be the simplest way to get to the grounding electrode system which originaes in the basement. Also this is an old concrete 8 story building with no exposed building steel. Please give me your thoughts.

Thanks Eric64

 

[dereckbc]

Re: Bonding of a Telephone Board. Multi family

If you are going to run it in conduit, you should bond it to the conduit at both ends.

 

[stamcon]

Re: Bonding of a Telephone Board. Multi family

Eric, have you read 800-40 (99 NEC)?

 

[hbiss]

Re: Bonding of a Telephone Board. Multi family

My first thought is what in the telephone rooms on the third and fifth floors need to be bonded to this ground. This might be a good idea or it night not even be necessary.

If it is necessary I would use something larger than #6 and run it separately.

Keep in mind that the only point that absolutely needs to be bonded is the protectors which should be located where the service enters the building.

-Hal

 

[dereckbc]

Re: Bonding of a Telephone Board. Multi family

Hal, what would a larger conductor buy you? At this length, a larger conductor (like a 750 KCM)has about the same impedance to HF as an # 6 AWG. I agree the protectors should be at the entrance, but that is not always the case. If they are protectors they should be refenced to the power supply ground bus rather than directly to earth. My guess it is a shield ground.

 

[ccha9219]

Re: Bonding of a Telephone Board. Multi family

Originally posted by dereckbc:
If you are going to run it in conduit, you should bond it to the conduit at both ends.

If you run conduit run pvc

 

[hbiss]

Re: Bonding of a Telephone Board. Multi family

My guess...

Yup, that's about all we can do without knowing what the ground will be used for.

Oh wait, I just see now that the original question says multi-family in the title. Hmmm, another clue.

If that's the case I really can't see why a ground is needed at each floor since all protectors should be located at the building entrance. These "boards" should only have terminals off the riser to serve each dwelling. What's there to ground?

-Hal

[ March 25, 2004, 09:29 PM: Message edited by: hbiss ]