Bonding fence

[romeo]

I am going to be inspecting a large PV system, that will be enclosed by a chain link fence. There are no means for bonding or grounding the fence, I am not sure if bonding is required.

Any advise would be appreciated.
Thanks in advance.

 

[jaggedben]

It would not be required, unless through some very strange design the fence is structurally connected to the racking for the arrays.

 

[WizBandit]

Chain Link Bonding

Chain Link Bonding

I am going to be inspecting a large PV system, that will be enclosed by a chain link fence. There are no means for bonding or grounding the fence, I am not sure if bonding is required.

Any advise would be appreciated.
Thanks in advance.

A typical "chain link" fence is a very loose system even when stretched. There is no secure grounding, mechanical nor electrical, between all the fence components. Connecting a ground wire from a "code compliance" grounded Photovoltaic racking system is not recommended. Here in Florida during the summer lightning season you would just be connecting a big "lightning magnet" to the very expensive PV array.

 

[Marvin_Hamon]

NEC 250.4(A)(4) requires that all normally non-current carrying electrically conductive materials that are likely to become energized be bonded to the electrical source. The question then is do you think that the fence may be likely to become energized? That will most likely depend on the relationship between the electrical equipment and the fence. If the fence may be likely to come in contact with an energized part of the PV system or other electrical equipment then it needs to be bonded. From what I have seen it would be unusual for the fence to need to be bonded.

I don't know of any NEC requirement that that the fence be grounded.

 

[ggunn]

If the fence has no electrical connection to the PV array, then it is a separate system. If it did not need to be grounded if it were somewhere else other than surrounding a PV array, it doesn't need it here.

 

[Marvin_Hamon]

The NEC paints with a pretty broad brush in this area. While I can't think up too many scenarios where a fence would have to be bonded it could happen. The NEC does not have a requirement that the conductive material has to be electrically connected to the PV system, only that it be normally non-current carrying, electrically conductive, and likely to become energized. Since there can be many non-current carrying conductive metal objects in the area it is the last requirement that pretty much drives the determination. Is it likely to become energized? Is it possible to energize a fence, yes. Is the PV system likely to energize it, that would be hard to do. About the only thing I could think of would be if there were overhead electrical conductors in the PV system that went over the fence. In that case if the conductors fell on the fence then they could energize it. Would this be a likely thing to happen, maybe. I have had an energized 12kV line dropped 5ft from me and I would not have thought that likely before it happened.

So I would not automatically assume that the fence is out of the running for bonding, just extremely unlikely.