I’m installing an a/c compressor on the opposite side of my house from my electrical main. The shortest run will be through the attic and down (about 50 feet) I live in Los Angeles. Since I have very limited attic access, I’d like to run 8 gauge wire (2 hot, 1 ground, 1 neutral) through armored flex. Is that legal? If I have to go to rigid, can I do it with plastic? There is some chance that I could bend a few pieces up through a small access hole, but rigid EMT will be very difficult to get into place. Does anyone know the best (and legal) way to do this? Thanks.
By the way, I’m pouring a pad, running the electrical, and getting everything ready for the A/C technician, so don’t bother posting about the problems of DIY air conditioning installation; I know what I don’t know and have no intention of making a mess of things!
Edited 6/28/2005 8:21 pm ET by andy
Replies
Probably have to check with your city - some allow romex, others require emt. Here is Chicago, only metal conduit is allowed. No pvc or romex. Regardless, I think (but I'm not an electrician.) the best way to do it is with emt. Can you cut a channel in the ceiling in a few spots to get the pipes up there?
Thanks, Rich. I checked the code books and it appears that I need rigid tubing (EMT or PVC) so I think I'll try to do it with PVC. Going to crack off the stucco between the rafter tails and see if I can feed the pipe in that way.
If you do go the conduit route, consider whether you would want to install an additional unused conduit (or two) along essentially the same route, for future use. (Eg, for cable TV or internet connections, or for new circuits for a kitchen remodel or whatever.)If the additional conduit might be used for TV/internet, however, and you use plastic conduit, try to keep the conduits separated by 3-6 inches.The conduit is cheap, and usually you can put in several for little more effort than putting in one. All of the cursing can be charged against the first one.
First you don't need a neutral for an AC compressor. They are strickly 240 loads.
And unless the city/state has more stringent requirments any of the common wiring methods (Romex, Metal Clad {the upgraded version of BX}, EMT, PVC, Flexible Metal Conduit) would all be acceptacle.
Thanks, Bill. I appreciate the clarification and many of your other posts.
Some of the condensor fans are 120V, so a neutral may still be required.
It is possible, but I haven't seen one (in very, very limited expience).What is interesting are dryers and stove.Now dryer could just as well been made with 240 motors and timers.Now there was a logical reason for 120 on stove. In the olden days you had 2 coils on each burner and the switch had several combinations of one or two coild and on 120 or 240 to get different heats.And there are the light bulbs.
Bill: I thought that PVC was verboten in residential spaces. Here in Nawth Jawja I had a three foot piece in my utility room & had to clear it w/ my inspector.DonThe GlassMasterworks - If it scratches, I etch it!
About the only limitations that I see are hazards locations and theaters (not going to read the sections for the exact limiations), hot (over 122), it can't support fixtures, and it can be used where subject to physical damage (unless it is so marked, ie sch 80).
I agree. Likely a Neutral is not required. Makes sense to read the label to make sure but it has been a very long time since I have seen a compressor that uses 240v but requires a 120v feed for a fan or controls.If NM is not allowed MC would be the perfect solution. Goes in almost as easily as NM, pull it in, but gives most of the protection of EMT. What it lacks in armor thickness it makes up in flexibility and ability to shift away from pointy threats.
This is a complicated issue. Lots of local code modifications to worry about, plus the issue of whether wiring in the attic can just lay across the joists or must be secured, whether it needs to be "protected", etc -- issues having to do with how much the attic is or isn't accessible/occupied. A lot will be up to the interpretation of the inspector.
In our neck of the woods, where you're doing retrofit in a barely-accessible attic, romex laying across the joists would be OK, so long as it was tucked back a bit so that it wasn't in danger of getting stepped on, used as a hand-hold, etc.