Coax next to Romex OK?

[NewKid]

Running coax cable (quad shielded) to several locations in the house and in some spots have little option but to run it right up against electrical wiring for several feet. Is this quad shielded coax good enough to eliminate interference from the electrical, or is there still significant interference? Also, does the inspector care about how coax is run?

[giddonah]

sometimes you gotta do what you gotta do. Yes, you can get interference from the romex. Best thing to do is minimize it as much as possible and hope it doesn't cause too many problems. What are you using the coax for, and how close to the romex do you have to go? If it's just a few feet, you should be fine.

The inspector could say something about it because, well, he's the inspector. We had one in UT make us move the LV wires because he didn't like them as close as they were to the power. We weren't too worried about it, and we are very picky about that kind of thing.

obviously, if you can find another path it would be best. Keep in mind that crossing power at 90 degrees is just fine though.

[NewKid]

Coax is for TV only. There's a couple spots where the coax will run in the same chase or conduit as romex for 4 to 6 feet. Pretty problematic to separate them, so I think I'm gonna give it a try as is, then do the nasty work if there's interference. Thanks.

[giddonah]

by code you can't run LV in the same hole or conduit as romex. If you're just running cable tv, then it might be ok with a little interference from the romex.

Keep this in mind too: if you try to change it by cutting the coax and splicing it to a section run outside the conduit, you're going to lose 6db at each splice. Cat5 is relatively easy to splice if the connections are done well, won't cause problems.

I'd test it asap and see how it goes before you get to the point of not being able to fix it. You could be fine. If an inspector sees it, he will probably make you fix it regardless.

[servant74]

You should get little or no interference on the Coax by running it near the romex. The coax is completely shielded internally. You could get some inductive coupling of high frequency RF from the coax on the romex but that doesn't cause issue with many things... unless you are running dsl or other higher frequency signals over the romex.

[Mike44]

What I've done sometimes to minimize any potential interference is to keep the data runs somewhat perpendicular to line voltage (romex cable) runs. Despite trying to keep your lo vo away from line voltage, there'll always be that one spot where you have no choice but to run it next to it. So what I do is zig zag the low voltage cable across the joist cavity where the romex is. Here's a quality image of what I mean :mrgreen:.

http://img20.imageshack.us/img20/617/lowandhighvoltage.jpg

Sure, it uses more wire and looks a little less neat, but for critical runs where signal integrity is essential and must be guaranteed BEFORE closing it in with drywall, this is probably your best bet.

Mike