Xfrmr Grounding

[mstrlucky74]

Have limited drawings with limited information. Need to ground my xfrmrs and don't know if building is steel? Was to achieve ground is to building steel, cold water main or ground bar, correct? Thanks.

 

[jumper]

I do not see permission to take it to a ground bus, even assuming it is the ground bus in the main gear. At best/worst you would take it to the electrode that serves the main. NEC 250.30(A)(4)

 

[Smart $]

I agree with Derek. The GEC is required to go to an electrode. Closest of metal water pipe or structural steel, if these electrodes exist. Otherwise to one of the other system electrodes. If you go to the main (service disconnecting means), you'll need to irreversibly connect to a/the GEC there, i.e. there is no provision to connect to the grounding terminal bus.

 

[mstrlucky74]

I do not see permission to take it to a ground bus, even assuming it is the ground bus in the main gear. At best/worst you would take it to the electrode that serves the main. NEC 250.30(A)(4)

Thanks. When you say take it to the electrode that serves the main what's entailed in that? Run ground wire from xfrmr to that electrode than what? Land the wire at the same location?

 

[Smart $]

Thanks. When you say take it to the electrode that serves the main what's entailed in that? Run ground wire from xfrmr to that electrode than what? Land the wire at the same location?

Yes.

Well, perhaps right beside the same location.

 

[infinity]

Have limited drawings with limited information. Need to ground my xfrmrs and don't know if building is steel? Was to achieve ground is to building steel, cold water main or ground bar, correct? Thanks.

Right or wrong it's acceptable to the local AHJ and common to install a ground bus near the service and bring all of the GEC's to the bus. That includes the service(s), water pipe, CEE, ground rods, common grounding riser(s) for the transformers, etc.

 

[Smart $]

Right or wrong it's acceptable to the local AHJ and common to install a ground bus near the service and bring all of the GEC's to the bus. That includes the service(s), water pipe, CEE, ground rods, common grounding riser(s) for the transformers, etc.

Code specifically permits this method without reproach where there are multiple disconnecting means enclosures (outside the enclosures). The point regarding the OP's installation is using the ground bus as a tap point is not specifically permitted, not to mention it is inside an enclosure.

IMPO, nothing wrong with doing it that way. :blink: