I am planning to convert a hay mow in a 100 year old barn to a play/sleeping area for family children. Wiring will be installed to provide lighting. The wiring in some instances will extend 10 to 15 feet along log beams. Since the barn is not tight construction and allows the entrence of rodents etc. during periods of none use (i.e., winter), would it be advisable/required to enclose the wiring in conduit to protect it from rodent damage etc.?? My concern is fire hazard if the wiring is damaged. I am writing as I am getting some opposition regarding the need for the wiring conduit in this situation. Need advise!

 

Conduit is never wrong, especially where rodents are present. If the barn will have agricultural use such as storage of hay or grain then in fact you may need special explosion proof fittings and fixtures but that is above my pay grade. Wait for the pros.

 

I would not use any exposed plastic, it would all be in EMT and steel boxes. BUt, I've recently been in active horse barns in NY with lots of NM running around, and I find that shocking. So, I can't speak for what is required in WI, but if it were my stable/barn, the wiring goes in pipe. Unattended wood structures with rats, etc. it should be your call.

 

What kind of opposition are you getting? Steel conduit (EMT) is always a good solution both aesthetically and rodent-resisting whenever you have open wiring. Code-wise, you might be fine using NM-B (Romex), or even MC, but conduit definitely is the safest answer.

 

If I was wiring it, I'd use either EMT or at the very least MC cable. I've seen too many hackjobs around here with NM to even install it in an outbuilding. Just my 2c.

 

I would only install EMT with compression fittings and steel boxes designed to be used on the surface. In conduit, individual conductors are used, with an insulated (green) ground wire.

I might pot exterior covers over the switches and receptacles, if I thought there was any chance of their getting wet, or just to rodent-proof them.

 

When wiring a old barn (i.e. 100 yr. old) does anyone have objections to enclosing exposed electrical wiring in flexible metal cable?? Or would non-flexible EMT be better? I'm thinking that flexible might be better because there are a number of sharp turns to go around.

 

Flexible metal conduit would be fine as would flexible metallic cable.

 

I would use nothing but PVC conduit and boxes. Anything subject to mechanical damage I would use schedule 80 PVC conduit.

 

I used MC cable before, as well as in my own shed/garage. If running conduit is an issue, like due to the framing of the barn, I'd use MC. Metallic would look better than PVC, IMO.

 

Barns and sheds are far too often damp and unless you use aluminum MC or aluminum conduit, steel cable and conduit will rust. PVC is impervious to degradation from moisture or from animal wastes. Even schedule 40 PVC will take some pretty hard knocks without damage. Smurf tube will NOT take anywhere near as much abuse as will PVC "rigid" conduit. Small bends and offsets may be made in PVC with the use of a heat gun and standard radius 45 and 90 degree bends are readily available. A well done PVC conduit job looks just as good as any EMT job, maybe better.

 

I agree with Justin. MC cable (MCAP) or EMT would be my first choices, although since it should not be exposed to water, I feel set screw fittings are fine. EMT will take decades to rust, especially in WI. PVC would be my fourth choice behind 1/2" flex conduit.