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Running romex in same joist space as water? #173970 01/24/08 10:39 AM
Joined: Oct 2004
Posts: 16
chimo Offline OP
I'm re-routing some circuits on a residential kitchen project, and was wondering:

Can you place electrical runs in the same wall cavity with plumbing? Good/bad practice? Could this be against code in some areas?

Building Codes & Related References
Re: Running romex in same joist space as water? [Re: chimo] #173971 01/24/08 10:54 AM
Joined: Jun 2007
Posts: 301
JValdes Offline
Yes, but I cannot quote an article to back it up. I know it is done all the time and I would not hesitate to do it myself. Someone else may disagree and provide an article for us. But I think the answer is yes.

Re: Running romex in same joist space as water? [Re: chimo] #173972 01/24/08 10:55 AM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
I don't see anything against doing so, but experience has suggested a few complications you'll need to address.

Pipes take up space. This can mean there's no room for a box, anchoring the cables can be difficult, and that the cables will need additional protection when the piping pushes them too close to the wall.

Re: Running romex in same joist space as water? [Re: renosteinke] #173997 01/24/08 09:16 PM
Joined: Sep 2007
Posts: 5
excellencee Offline
New Member
I had a HO/plumber who forbid me from running romex in the same stud/joist space as his copper pipes. He claimed electrolisis (sp?) causing pinholes in his copper. He was/is the only plumber that ever identified this as a problem. BTW I run romex in the same bays as plumbing.

Re: Running romex in same joist space as water? [Re: excellencee] #174007 01/24/08 10:38 PM
Joined: Apr 2004
Posts: 810
Theelectrikid Offline
Welcome aboard excellencee, from another member from the Commonwealth of PA.

Ian A.

Is there anyone on board who knows how to fly a plane?
Re: Running romex in same joist space as water? [Re: Theelectrikid] #174023 01/25/08 12:50 PM
Joined: Jul 2002
Posts: 717
macmikeman Offline
You can. However, if the spacing is tight, you might want to consider the ambient temperature if you find that your cables are physically touching the hot water pipe. In that case de-rating may be required, depending also on the length of the contact.

Re: Running romex in same joist space as water? [Re: macmikeman] #174025 01/25/08 01:04 PM
Joined: Oct 2002
Posts: 482
Zapped Offline
In the same joist/stud bay? Sure. I've worked with so many plumbers I couldn't begin to take a swing at the number, but I've never heard anything about electrolysis or any such thing like that.

Touching? No. Hot water, cold water, doesn't matter. Not a good idea. Vibrations, heat, cold, etc. There are too many variables to even consider doing this. You can get around them without problem. If not, at least use some pipe insulation jacket between your wire and the pipes.

Good Luck!

Re: Running romex in same joist space as water? [Re: Zapped] #174038 01/25/08 02:50 PM
Joined: Aug 2001
Posts: 7,520
pauluk Offline
We do it all the time over here, where hot-water central-heating systems are the most widespread so it's common to have copper pipework running all over the house, not just in the kitchen/bathroom areas.

Re: Running romex in same joist space as water? [Re: pauluk] #174216 01/29/08 12:50 PM
Joined: Jun 2006
Posts: 613
mikesh Offline
Plumber often wrap BX to prevent electrolosis but romex is no problem as it is insulated. excellencee's HO/plumber was thinking bx but he was a plumber and what does a plumber know about electrical installations ;-)

Re: Running romex in same joist space as water? [Re: mikesh] #174223 01/29/08 06:03 PM
Joined: Jul 2007
Posts: 85
WireNuts29 Offline
I have first hand experience with a hot water pipe going to the shower, melting into the range feed in my parents house.The house was built in early 70's. this happened probably 6 years ago. The problem most likely started as soon as the house was occupied. But over time the romex jacket and conducter jacket was melted. the only reason for finding the problem was a random shock when getting in the shower, and touching any grounded metal around it. I.e the handle, or drain. I've never seen this problem anywhere else. From then on I always maintain a healthy spacing when running romex anywhere near hot water pipes.

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