Bonding security fences

[jim dungar]

This is not about bonding fences around open air substations/switch yards.

I have an outdoor 34.5kV metal-enclosed fusible switch lineup. The equipment sits on a concrete pad and is surrounded by stone, river rock not gravel. There is a ground ring installed under the stone around the gear and pad, the metal-enclosed gear is bonded to this ring. There is a chain link fence surrounding this equipment yard which comes within 3ft on the sides, 5ft on the rear and 10' in front. The fence has a man gate and a double door vehicle gate.

In the old days, a bonding jumper from one fence post to the ground ring was considered sufficient for bonding. I am not completely comfortable with the simple method.

I think there should be bonding at each corner post, with jumpers across the gates. I do not think a perimeter ground ring would be required at the fence line.

Does anyone have any comments or resources?
Soares does not address bonding chain link fences and IEEE-80 is vague on actual details.

 

[John120/240]

off topic duh

 

[jim dungar]

Check with your local POCO & see how they do it.

This is not for a utility switch yard or substation, there are no open conductors, there is no barbed wire. This is no a situation where step potential is an issue.

NEC 250.190 requires the fence to be grounded. How do people 'ground' chain link?

The requirements in IEEE-80 and the 'Design Guide for Rural Substations' seem overkill. Effectively they want a connection to the ground grid conductor every 75', this fenced area is only about 30' long.

 

[don_resqcapt19]

The last one I did was for 5kv to 480 volt sub with no exposed live parts. The job specs required a connection to the posts on each side of the gates, then every other post and a flexible jumper to the gates. It did not require any direct connection to the chain link fabric itself. I am sure that was very much overkill.

 

[jim dungar]

The last one I did was for 5kv to 480 volt sub with no exposed live parts. The job specs required a connection to the posts on each side of the gates, then every other post and a flexible jumper to the gates. It did not require any direct connection to the chain link fabric itself. I am sure that was very much overkill.

Thanks, I was pretty sure that simply bonding each fence corner post and across the gate, was not too extreme.

 

[Hv&Lv]

We connect directly to the chainlink at every other post. It only takes 6 more inches of wire and a crimp connector.(nonreversible) Of course, we use the specs you mentioned.



To answer your question,

How do people 'ground' chain link?

Crimp connector.

I agree, it seems like overkill since the chain link you ground to is weaved in and the continuity depends on how tight the fence is.

 

[jim dungar]

We connect directly to the chainlink at every other post. It only takes 6 more inches of wire and a crimp connector.(nonreversible) Of course, we use the specs you mentioned.

For open air yards i require a ground conductor to be woven all the way up to the barbed wire.

But this is simply a security fence, which i probably would have ignored except it is within 'touching' distance (<5') of the equipment enclosure.

 

[ceb58]

Thanks, I was pretty sure that simply bonding each fence corner post and across the gate, was not too extreme.

That's the requirement at our communication towers. Corners, gate post, flex ground to the gates all cad welded to the ring.