Secondary Handhole Lid Grounding (120V 1ph to 480 3ph)

[SCLstandardsengineer]

I am in the process of putting together a standard for grounding metallic handhole lids. I was going to bond the lid and frame to a ground rod at the bottom of the handhole. My question is is there an NEC rule dictating whether to bond that to the neutral running from the transformer to the load which passes through the handhole? Thanks

 

[iwire]

Grounding the lid to only a ground rod driven in the earth would be entirely pointless and ineffective at the voltages you are talking about.

You need a metallic grounding conductor of some type back to the source.

 

[Buck Parrish]

Iwire is right . These metallic lids have became an electrocution hazzard in some areas with deterioating grounded conductor connections, and grounding connections.

It started with dogs being killed . Recently I read some where people have been killed. It is most likely due to stray voltage.

You need to do some research of the electrical system.
Then may be treat the lid same as you would service equipment.

I don't think the NEC 08. adresses the matter. But interpetted it may.

Check out the Mike Holt News Letters. I am pretty sure that is where I read the article.

 

[SCLstandardsengineer]

Thanks. Your comments have reinforced what I thought should be done.

 

[Buck Parrish]

Your welcome.

 

[chris kennedy]

My question is is there an NEC rule dictating whether to bond that to the neutral running from the transformer to the load which passes through the handhole? Thanks

How about this?

250.4 General Requirements for Grounding and Bonding.

(A) Grounded Systems.

(3) Bonding of Electrical Equipment. Normally non?current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.