Grounding

[bartongr]

I am installing new ac units with varible speed drives. The Building was built in the early 70's,
there are no grounding buses in our panels. The conduit served as utility ground, what should I do to ground the unit correctly? I do not no what the code was in the 70's or what type of earth grounding system we have. Could I use building steel or should I go back to switch gear for grounding.

 

[roger]

Re: Grounding

Using the conduit as the EGC was legal in the 70's as well as now.

Now you can simply install a ground bus in the distribution panel you are serving the new A/C's from or go back to the main switch gear.

You can not run a conductor to building steel for an EGC.

Roger

 

[bennie]

Re: Grounding

Remember that when there is no ground conductor of wire, there is no need of a bus, only tight lock nuts