Electrical wire inside or ourside vapor barrier?

Question

I'm going to be installing a vent fan this afternoon and will have to make a short electrical run to power it. Since it is a vent fan, it is obviously going in an exterior wall (2x4 studs, insulation, and vapor barrier).
My first instinct is that the wire should run through the 2x4s (obviously) and on the interior side of the vapor barrier. Am I right or am I missing something?

Answer 1

It doesn't matter as far as code or the wire goes. Usually the wires are outside the vapor barrier as they run along or through the studs and the vapor barrier is on the inside stud surface just under the drywall or paneling. In any case, the space inside the walls or under the roof surface is considered a dry location.

Answer 2

Guardrail jim is correct that Honda stopped that practice long ago. However, it didn't have a thing to do with shorts or wire failure, it was because Honda foolishly used a common die cast switch housing that contained the electrical switches and on this same housing was mounted the rear view mirrors, clutch & brake lever. This is what would happen; you'd drop your bike or accidental clip the mirror or lever on the door or garage wall, the mirror or lever would twist backwards rotating the electrical switch housing. Since the wires were inside the handlebar, the housing would shear them off slick as a whistle. You then had a wiring harness inside the handlebar that was too short to be pulled out and the ends re-soldered to the switches, so you either replaced the entire harness inside the handlebars or removed everything, soldered in new splices and then ran the new wires to the switches. You couldn't use the same wire because the splices would all be at the same place and too big to fit into the hole in the handlebar. So your comparison of Harley to the super smart Japanese if full of holes. In addition, not everybody knows, or should I say thinks it causes problems because it doesn't. If you want to talk about problems, ask why the Japanese for years have mounted their fuse block immediately next to the battery so that battery fumes can corrode the connections. And as far as the Japanese bikes never having electrical problems, what brand of sake have you been drinking? Over the years, I've had to chase down every kind of electrical problems imaginable on Jap bikes. I ride Japanese bikes, so I know what I'm talking about.

Answer 3

I was told a long time ago that it doesn't matter which side of the vapor barrier the wire goes. Just don't wreck the vapor barrier and make darn sure that you put nail guards wherever you can along the wire.
The vapor barrier has little effect on wiring, so it doesn't matter.

Answer 4

Use some indoor/outdoor wiring and you should be fine. But penetrating the vapor barrier would be a bad idea, I would think.

Answer 5

wire must be 1.5" from interior wall so nail cant hit it or metal plates go on studs.
wire & vapor barrier dot matter.

Answer 6

you are right