Old Rigid Electrical Black pipe For Ground

[harborrick]

City of L.A California
Rewiring a few units with old black pipe.Are we allowed to use blackpipe for ground.Or do we run ground wire with drilling and tapping old metal boxes.I will be using existing conduit to re feed new circuits.
Thanks Rick

 

[al hildenbrand]

Re: Old Rigid Electrical Black pipe For Ground

Unless you have local ammendments to the NEC to the contrary, RMC is a great ground. No need to run a seperate EGC in the conduit. Add a bonding jumper from the box to the device as needed per NEC.

 

[harborrick]

Re: Old Rigid Electrical Black pipe For Ground

I did not ask for any amendments.I will double check on Monday.I do not see any reason or common sense to use conduit as ground.I thought we couldn't use black pipe for ground.Thanks Again
Rick

 

[iwire]

Re: Old Rigid Electrical Black pipe For Ground

Originally posted by harborrick:
I do not see any reason or common sense to use conduit as ground.

It is done all the time.

What does not make sense to you?

Threaded conduit has been, and still is an NEC acceptable grounding conductor. 250.118

Many times job specifications are more restrictive than the NEC. Many job specifications require a copper grounding conductor. Along with checking for amendments look at the contract documents.

 

[kendog]

Re: Old Rigid Electrical Black pipe For Ground

I think he might be thinking about gas line. The way I always delt with gas line is, the gas line is required to be grounded but I personally would never use it as a grounding means (if there was gas or oil running through it) but in your case I don't see any problem.

[ December 31, 2004, 09:12 AM: Message edited by: kendog ]

 

[iwire]

Re: Old Rigid Electrical Black pipe For Ground

Originally posted by kendog:
I think he might be thinking about gas line. The way I always delt with gas line is, the gas line is required to be grounded but I personally would never use it as a grounding means (if there was gas or oil running through it) but in your case I don't see any problem.

Well now I am confused, if there is gas or oil running through it hopefully there would be no conductors in the pipe.

Without conductors inside the pipe it can not be used for 'grounding' the grounding means for any circuit must run with the circuit conductors.

Older electrical conduit came painted black, I believe that is what he is talking about.

Bob

 

[renosteinke]

Re: Old Rigid Electrical Black pipe For Ground

I believe that he is talking about using conduit as a ground. So many Californians I've met believe that you must run a ground wire, I suspect that this may be a California, not NEC, requirement.

Wherever you are- GET COPIES OF ALL CODES- then READ them. Too many "professionals" limit their learning to what they were told in their first job....

 

[al hildenbrand]

Re: Old Rigid Electrical Black pipe For Ground

I'll bet that the "units" harborrick is talking about are single dwelling units from the first half of the 20th century and the original wiring method was Rigid Metal Conduit, mostly 1/2" with some 3/4" and maybe an example of 1". RMC was painted black as an oxidation inhibitor. The steel boxes of that day were also simply painted black.

It was (and is) a Cadillac wiring method in my opinion. I find numerous examples of it in the old inner cities of Minneapolis & St. Paul where I work.

One of the characteristics of it, here, is the use of the luminaire canopy to splice wires in. I will find four 1/2" rigid, each with 2 or 3 conductors, all presenting in a 4" round flat pan only 1/2" deep. All the splices will be twisted, soldered, rubber taped & then friction taped. . .big & bulky. There will be a 3/8" NPT fixture stud in the pan as well, for hanging the old luminaire.

Wall cases are commonly 2" x 3" x 2-1/2" deep, although 4 bys with black painted plaster rings will be sprinkled about as needed.

 

[harborrick]

Re: Old Rigid Electrical Black pipe For Ground

Al,
You hit it on the screws.Can you imagine how much time it took to wire those units.Their work was done to perfection.
This conduit was installed for electrical use only.We don't need to read into it with gas or oil.
In the old days their were no grounded outlets.I see no code on coated black conduit.Common sense would say this method were acceptable.
I will double check with that city inspector.
Thanks Again Rick