Gas and electrcial trench seperation

[Alden]

I have a customer in Michigan (2005 NEC) doing a 5 foot deep trench for water to a detached barn. I plan on tossing in some PVC for the feeder to the barn also. The customer also wants a gas line put in the same trench. I told him there is no NEC requirement for seperation. Does anyone know of a gas code that would require seperation?? His "handyman / gas employee doing side work who didn't know what CSST was when I asked him if that's what he was running" said there was. I do not know what gas code is being used here.
Thanks!

 

[SEO]

No problem with NEC and don't know of any gas code violations either. Is the gas line natural or propane? Check with local mechanical AHJ.

 

[dreamsville]

If it's NG I'd contact the supplier for questions. Here's a link to NG service map for Michigan. :smile:

http://www.dleg.state.mi.us/mpsc/gas/servarea.htm

 

[hardworkingstiff]

If the trench is being dug with a bucket (in lieu of a trencher) then I'd just keep the gas to one side and the electrical on the other.

 

[realolman]

What would happen if you had to dig up one of the three?

If I were the owner, I think I'd have expected the installers to have shown a little more forethought than to have to ruin all three installations to dig one up.

I think you could probably dig up one of two in a ditch, but I think it would be hard to do one of three.

 

[4SPARKS]

I'm in Jersey and gas company/AHJ requires 2' seperation between gas and electric and metallic marking tape to be installed in trench

 

[nhfire77]

The local POCO here requires 3' of seperation from NG or propane, if you use bottled gas.

 

[Alden]

This gas line is a natural gas feed fed from the house. The home owner is using a 12" bucket for the trench. Since it is her first attempt at digging the trench, the bottom is VERY uneven. The 100' span varies +/- 2 feet in depth. They are going to bury water and gas, then back fill with sand to give me a nice even floor at about 2 feet (18" required in this install) I'm happy now and their "gas" guy is happy. Now I just have to convince the inspector that the voltage drop in this case (which I did do calculations on to verify) is still a F.P.N. and is NOT enforcable. :roll:

Also, the inspector, which is a personal friend and all around good guy, keeps inspections seperate from friendship, which I greatly respect. He is letting me use 310.15 B(6) to size the 100 amp feeder to the pole barn. I get conflicting answers from inspectors as to whether or not to use this table or should I be using 310.16.

 

[SEO]

A barn is not a family dwelling unit so 310.15 (B)(6) would not apply. Use table 310.16.

 

[charlie]

A barn is not a family dwelling unit so 310.15 (B)(6) would not apply. Use table 310.16.

No kidding. :smile:

310.15 (B)(6) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders. For individual dwelling units of one-family, two-family, and multifamily dwellings, conductors, as listed in Table 310.15(B)(6), shall be permitted as 120/240-volt, 3-wire, single-phase service-entrance conductors, service-lateral conductors, and feeder conductors that serve as the main power feeder to each dwelling unit . . .

 

[Alden]

This interpration of 310.15B(6) is the same one I have. What confuses me is about 70% of inspectors say I can use this table for a sub feed for a pole barn. I would like use 310.16 to size the wire, but when I bid against other contractors who are using 310.15B(6), it could mean the difference of getting the job or not. There are a some inspectors that really know their stuff and use the correct table. My confusion is bidding a job and trying to know what the inspector will enforce. While MIch is on 2005, one would think all interpretations of using this table would be the same.

 

[SEO]

I find it hard to believe that 70% of the inspectors call it that way. I know of one that doesn't. That makes the call a lot tougher for you, to get the job you have to violate the NEC with the inspectors blessing. Something is not right.

 

[nunu161]

I think the gas lines have to be buried deeper then the electrical.

 

[Alden]

Nunu161, please cite a reference to your claim.
Also, the 70% claim also includes small sub panels in the same dwelling unit. Because it is NOT the main feeder for the dwelling unit (but it is the main feeder for the sub panel) I use 310.16. Most inspectors say I could have used 310.15B(6). I thought since this was NOT the main feeder for the dwelling unit, 310.16 would apply. Have I been wrong and over engineering the jobs or has this section not been applied correctly?

 

[SEO]

Alden I think that some of your inspectors are wrong look at posts 9 and particularly 10. Look at what Charlie underlined .

 

[LarryFine]

Now I just have to convince the inspector that the voltage drop in this case ... is still a F.P.N. and is NOT enforcable. :roll:

He is letting me use 310.15 B(6) to size the 100 amp feeder to the pole barn.

Interesting that he's over-picky on one thing and under-picky on the other. :-?

 

[LarryFine]

There are a some inspectors that really know their stuff and use the correct table. My confusion is bidding a job and trying to know what the inspector will enforce. While MIch is on 2005, one would think all interpretations of using this table would be the same.

That's what supervisors are for. I'd have a talk with the head inspector (or equivalent) about the inconsistant enforcement.