Existing Grounding issue

[john37]

I have this situation where there the existing transformer is only grounded to a galvanized water pipe within the electrical room. It appears that they connected the ground wire from the XO on the transformer and ran a ground wire out of the enclosure to the nearest galvanized water pipe. The transformer is located in one enclosure with the 480V/277 and 208/120V switchboards. In order to properly ground the service, I would need to provide a ground rod(s) and would I need to re-route the existing ground wire to a copper water pipe or is it okay to still have the existing ground at the galvanized water pipe as long as we get the 25 ohms or less resistence? Do I need to also provide a ground to building steel as well to meet code grounding requirements? I'm not sure when it comes to existing conditions on what is required. Thanks.

 

[Smart $]

Code only says metal underground water pipe... so copper or galvanized makes no difference.

IIRC, in industrial situations, the metal water pipe can be used to extend the water pipe electrode beyond 5 ft. from entry.

Building steel, if it qualifies as a grounding electrode, must be used as such. Otherwise, it must still be bonded.