ECN Forum

RNMC in Gas Stations

Posted By: George Little

RNMC in Gas Stations - 04/25/05 08:51 PM

Does anyone see a problem with usin RNMC for the branch circuits feeding gas pumps. We are talking about the above ground portion on the supply side of the seal offs. The area involved is unclassified and the proper bonding is applied after the seal and rigid metal is installed from the seal off to the islands and there is a "bonding" wire pulled in the RNMC from the gutter at the building to the Service panel. I guess my interest is the strict bonding requirements in the classified area are required to be carried back to the Service or the sub panel where they receive the power.
Posted By: walrus

Re: RNMC in Gas Stations - 04/26/05 10:37 AM

Probably can't help with the question but maybe I can learn something [Linked Image] Where is the PVC?? Rigid comes into the trough? and then PVC goes to the panel??. How did they bond the rigid??
Posted By: George Little

Re: RNMC in Gas Stations - 04/26/05 11:49 AM

Guess my description is bad. We have RNMC run from the panel to the trough and RMC run from the trough to the islands. There are seals at both ends of the RMC and bonding locknuts on the RMC. The is a bonding conductor pulled through the RNMC and connect to the metal trough on one end and the grounding buss in the panel at the other end.
Posted By: arseegee

Re: RNMC in Gas Stations - 04/27/05 12:11 AM

Our state just changed the requirements for fuel dispensing about two months ago.

Before, it was required to be RMC the whole way. Now ten feet after the trough seal off has to be rigid and EPVC to the pumps and tank monitors except for the last ten feet which changes back to rigid with another seal off. We bond with EGC at both ends.

A lot easier to run and a lot easier on the pocket.
Posted By: royta

Re: RNMC in Gas Stations - 05/12/05 04:42 PM

arseegee - Your state now requires the use of RNMC between first and last 10 feet of RMC? Or do they now give you the option?

I learned the electrical trade by wiring gas stations. This is a good reason why my knowledge of the the entire electrical trade is so limited. Anyway, we did only one job with RNMC between the first and last 10 feet of RMC. It was also our last job. The 2-wire communication wires for the Gilbarco dispensers picked up lots of noise, so we had to pull in shielded twisted pair. That and somehow one of the lines broke or someone forgot to glue a joint. The latter problem could have been prevented, but we just felt that RMC was just a safer bet.


George Little - I'm not sure on whether using RNMC is up to code, but I would rather use EMT. It just looks cleaner.

[This message has been edited by royta (edited 05-12-2005).]
Posted By: walrus

Re: RNMC in Gas Stations - 05/13/05 10:15 AM

I learned the electrical trade by wiring gas stations.
I learned the same way [Linked Image] I also suffer with a lack of background in other types of installs.

If using RNMC in a tank hole, where the RNMC leaves the tank hole and enters a trench, settling in the tank hole and not in the trench can snap the RNMC right off. Seen it happen before and would not use RNMC until I was completely in the trench
Posted By: arseegee

Re: RNMC in Gas Stations - 05/14/05 12:52 AM

royta, you can still run rmc the whole way here. And yes, twisted shielded pair is a must.
Posted By: renosteinke

Re: RNMC in Gas Stations - 05/14/05 02:44 AM

Remember that materials are required to be suitable for their environment. While I don't have a problem with PVC in a non-classified area of a gas station, I would also like to point out that PVC can be damaged by mayn things found around gas stations....gasoline in particular, though carburator cleaner, some parts cleaners, and starting fluid lead the list. Please consider the exposure of the PVC to these solvents where it is run.
© 2020 ECN Electrical Forums