dumb question about running the wire

[mikeyr]

I am about to start finishing my new garage. A 100AMP panel was put in the garage and I have 1 220V plub and a few lights, a few plugs in random locations wired in and passed inspection.

I need to run wires to the other end of the 40ft. garage and one of thing I have to run is whatever size wire I need I need to support my 50amp welder and 30amp compressor, I don't mind making 2 runs of wire or one big mother and splitting it at the other end. BUT my real question right now is, where to run the wire, I want to run it near the peak of the roof. I want to do this because that way it will be hidden and I won't have to drill a lot of holes in 2x4 studs. It effectively adds about 17ft. of wire run because I have to go up near the peak, I doubt that is a issue if I size the wire properly, correct ?

My garage has 2x4's about 2 ft. down from the peak on all the rafters, that is where it will get drywalled in a short while. So the wire would 2ft from the peak, it gets pretty hot up there, is that a issue ? I seriously doubt it since wires are run all the time in attics but this time its near the hottest point.

Also, individual wires in conduit or would romex be good enough ?

I am going to follow what the electrician did that has been signed off, and I have done wiring before so not too worried, just don't know it all yet

 

[A_Pmech]

Mikey,

Ampacities of common conductors are based on an 86F ambient temperature. You need to de-rate your wiring for the ambient temperature in the attic, especially if you make connections or terminations in that space. I believe NEC tables 310-17 and 310-19 may be of help to you in de-rating the conductors for increased ambient temperatures.




Edit:

Unless your area requires they be in conduit, I see no reason why you can't use Romex cable.

 

[mikeyr]

Cool, see I knew it was a dumb and stupid question but good thing I asked, had not thought of heat doing that.

And by the way, I think the 2x4 across the roof is called a collar tie, we had joist spanning the spanning the garage that of course got in the way of my lift and my contractor moved the joists way up, he now calls them collar ties. I could not think of it in my first message.

This is so cool, looking forward to getting it done and finally working on my car.

 

[Torque1st]

Make two runs, one for the welder and one for the compressor. Refer to your welder manual for the welder breaker requirements. Welders have different requirements. You can also wire the welder outlet for the full 50A with a 50A breaker.

 

[OccupantRJ]

Just asking, but what is going to keep your walls from bowing out, and your roof sagging over time, with collar ties only 2 feet from the peak? Was this done only in an area just big enough for the lift? If not, you might want to question this. Unless there are engineered scissor trusses, this doesn't sound very well designed. (only my opinion) Something has to keep the weight of the roof from pushing out on the top plates.This following idea may not be to building code for your area, but I have seen a lot of older warehouse type buildings here using tension rods with turnbuckles or cables spaced horizontally through the room at strategic locations to help tie the top plates together to prevent the swayback roof condition that you may have seen on old buildings while cruising through the countryside. This broadens the triangulation of the roof structure.

RJ