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#83887 - 02/23/03 02:05 PM Underground: How close Can Gas & Electric conduit be?  Offline
Junior Member
Joined: Feb 2003
Posts: 1
Menlo Park, CA USA

How close and how deep do gas and electrical conduit need to be in someone's backyard in northern CA?

Wiring equipment for Endlwss Pool in small backyard.

9inch wide by 18 inch deep trench was dug to bring gas & electric out from back corner of house.

Can gas be at 18 inches deep, and electrical conduit at 12", (less than one foot apart horizantally, and six inches vertically)?

Or does the trench need to be widened? Or a second trench dug?

Thanks in advance for your input.



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#83888 - 02/23/03 03:06 PM Re: Underground: How close Can Gas & Electric conduit be?  
stamcon  Offline
Joined: Mar 2001
Posts: 329
So San Francisco CA
Mike, the 2001 California Plumbing Code states the minimum cover for horizontal metallic gas pipe to be 12". Also, 1211.7 "Underground ferrous piping shall be electrically isolated from the rest of the gas system with listed or approved isolation fittings installed a minimum of six(6)inches(152mm) above grade.
I don't know the horizontal distance required by code, but PG&E wants a 6" minimum (12" typical) horizontal separation.
The electrical pipe cover depends on the pipe material(or direct burial cable), voltage, vehicle traffic and if concrete will be used as cover.

#83889 - 02/23/03 06:23 PM Re: Underground: How close Can Gas & Electric conduit be?  
Elzappr  Offline
Joined: Dec 2001
Posts: 270
Just to expand a bit about the PGE requirements: "The Power Company will not install electrical conductors in a common trench with non-electric utilities such as water, gas, and sewer unless unusual conditions such as adverse soil or route restrictions exist. All such installations require the prior approval of the Power Company. -- pg.28 Oregon Electric Service Requirements (applicable to work by PacifiCorp and PGE)
Joint use trenches for electric lines, like transformer secondary service lateral conductors, communication, and signal conductors, telephone, Cable TV are ok if there is 12" separation horizontally (edge of conduit to edge of conduit...not center to center)

Anyway, although this stuff isn't directly applicable to your query Mike, it might serve to indicate that gas and electric might not be combined in a "joint trench", as a general rule.

[This message has been edited by Elzappr (edited 02-23-2003).]

#83890 - 02/23/03 06:50 PM Re: Underground: How close Can Gas & Electric conduit be?  
stamcon  Offline
Joined: Mar 2001
Posts: 329
So San Francisco CA
This link is for a section from PG&E's Green Book. Scroll down to 2.3.3 - Joint Trenches
There are also diagrams shown.

#83891 - 02/23/03 07:28 PM Re: Underground: How close Can Gas & Electric conduit be?  
caselec  Offline
Joined: Apr 2002
Posts: 558
San Jose, CA
PG&E does not prohibit gas and electric conductors from being in the same trench and would prefer them in the same trench in most cases but do have clearance requirements. I'm sure Mike is asking about customer owned facilities that do not have to follow utility rules so unless there is a local code there would not be any minimum horizontal clearance requirement. There could definitely be a problem with the depth of this trench though.

Mike, I hope you are planning on getting an electrical contractor involved with this project. Wiring a swimming pool is definitely not a DIY project. If proper grounding and bonding requirements are not followed it could result in serious injury or death to yourself, family members and friends.


Curt Swartz

#83892 - 02/23/03 08:05 PM Re: Underground: How close Can Gas & Electric conduit be?  
Elzappr  Offline
Joined: Dec 2001
Posts: 270
Thanks Stamcon for bringing to light the Green Book. The Electric Services Requirements book was the only publication provided to me by PGE, and no mention of the Green Book was made. I've been planning to visit my PGE office soon in order to get an updated copy of the Service Reqs., and now I can ask them about why their advice differs from one publication to another. I suppose the Service Req book neglected to mention that their prohibition against joint electric and gas pertained to just non-PGE gas lines.
Anyway, as Caselec mentioned, it has to be checked out locally. In light of the Green Book info, there doesn't seem to be any big objection to running gas and electric at least 6" away from each other...enough to not dig up one when trying to dig up the other.

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