Using a chain link fence as GEC??

[kwired]

The chain link fence at my house is a gec just because it is.

It is an elecrode - it is not an electrode that the NEC requires you to utilize.

How exactly does one bond a fence, and get every part of it to be electrically continuous in a code-compliant manner?

Do you need a split bolt or grounding U-bolt on every post, every brace pipe, every fabric segment, and every intricate fence fitting? Or do you just need to connect to major posts?

I'd imagine that there exists some amount of electrical continuity among the fence fittings and components, even if it isn't tested for such a purpose or installed by electricians.

Not bonding it at all is code compliant - at least for under 1000 volts and/or when the fence is not a barrier around over 1000 volt equipment anyway, did not look up any rules for over 1000 volts so I am not certain what may be required by NEC. Most places you do see such bonding are not NEC applications either.

Thank you all for taking the time to respond.

Are we not concerned about voltage gradient? Does each fence post being connected to Earth place the fence at equal potential or does it constitute a difference of potential?

If this is acceptable, then why is placing multiple ground rods bad practice? Isn't it electrically the same thing? ie, if it think it would be interesting to see in schematic how this differs from having multiple GEC.

i dont mean to ramble...just trying to understand what the difference is.

Also, just because its common practice dosen't make it correct or safe.

Please expand...

Thanks,
One line diag

There is a voltage gradient around all electrodes (intentional electrodes or not)if there is current flowing through the electrode. But the issue with such a loosely joined fence like you have with a chain link fence is each post (electrode) is not solidly bonded to the fence, which means unexpected voltages along that fence can occur, getting a solid bond between all loosely joined components puts them all at the same potential, the voltage gradients will be in the earth around each post or electrode, but is no different then any other object that is connected to the electrical grounding system that also has direct earth contact.

If you are intentionally using these posts as a grounding electrode they would need to meet size/length requirements (of the buried portion) in 250.52(A)(5) for rod and pipe electrodes, otherwise they are not a NEC compliant electrode - but that doesn't prohibit you from bonding to them - just means you must have some other NEC compliant electrode where an electrode is required.

 

[nvpowerdoc]

IEEE Std. 80 covers this (grounding and bonding) requirement in MUCH greater detail. It used for determining Ground Potential Rise during a ground fault condition for Step and Touch Potential values between adjacent "grounded" equipment.