So I'm thinking of insulating my attic. I have a slab foundation and all my electrical runs through the attic. I know certain hot features (light fixtures, transformers, etc) need a certain amount of clearance around them so they can dissipate heat - that's in the electrical code. Do runs of individual cable, runs of multiple cables (which have to be derated just because they're near other cables) or junction boxes need to be kept clear of insulation too? The derating business makes me think they need space to dissipate heat, but I can't find anything on the topic. Also, if they are on the house side of the summer heat (it easily reaches 140 up there) wouldn't that be better anyway?
2007-01-20 05:34:41 · 7 answers · asked by Robert G 1 in Home & Garden ➔ Do It Yourself (DIY)
i have to laugh occasionally, when i think about how the NEC (National Electrical Code) has gotten folks so scared..Article 310 has always stated the ampacities of wires...#12 guage copper, according to Code, can handle 30 amps of current. (Article 310-16) although it stipulates that #12 will be attached to no more than a 20 amp breaker or fuse.
Think of your average bedroom in a house. 6 to 8 receptacles. per. room..max current load...1 clock radio...1 lamp. 1 television...potentially 5 amps on a set of wires meant to carry at least 30...Unless you have a factory in your house, with the continuous load factor figured....no more than 80% load per circuit breaker...don't worry about it...your house is never gonna get hot enough, to affect the wires...
keep the NEC rated clearances for the inductive loads....i.e. transformers,,,flourescent lites...Can lites need space to breathe, as they are resistive loads...both produce heat...give em room..
Continuous loads are a major factor with the NEC and NFPA.These are loads of three hours or more. i doubt that anyone on these boards has a continuous load...unless they are growing...something....
Keep your cables as best as you can on top of the insulation...let everything breathe...and unless your growing weed or making beef jerky, with lites...don't worry about the heat factor...remember...CONTINUOUS LOADS...
2007-01-20 15:35:17 · answer #1 · answered by Anonymous · 0⤊ 0⤋
I wouldn't worry about the actual electrical cable touching the insulation. If properly installed, electrical cable does not get hot to start a fire. The Junction boxes are the same way, you can cover them, just make sure they are accessable and the insulation can be easily pushed aside if you need to get into them.
The only thing I would be worried about is if you have recessed lighting. There are 2 types of recessed lighting, one which can be completely covered in insulation, and others which have to have an air space around it.
It usually says it right on the fixture if you can have insulation touching the fixture.
If you got recessed lighting that cannot touch insulation, then its just a matter of determing how much clearence it requires and if your laying fiberglass you can just not insulate that area, or if your using blown in insulation, just build a little wooden box to go around each fixture to prevent the insulation from touching it.
I don't have the specs infront of me, but if you go to home Depot look at the fixtures there and it should give you an idea of what you have to do.
2007-01-20 15:56:12 · answer #2 · answered by metrodish 3 · 0⤊ 0⤋
The insulation will not affect your electrical wiring, even around junction boxes. There is one area of concern, however. If you have recessed can lighting, you need to determine whether they are designed for contact or non-contact with insulation. If they're not rated, and a re newer fixtures, they will automatically turn off when they reach a certain heat limit. If they're really old, they might be a hazard. But many of today's recessed cans are designed to be fully covered with insulation. If they're not, simply leave a space around the perimeter of each can and they will function safely and properly.
2007-01-20 10:38:31 · answer #3 · answered by Turnhog 5 · 0⤊ 0⤋
Insulation works by inhibiting the transfer of energy or lack of energy to another area. So yes it works for cooling and heating, but it does no good to only block air flow. Try putting a thermometer inside a blown up balloon and put it in the fridge. The air inside the balloon didn't travel from the outside into the inside. It merely transferred the lack of energy into the balloon and the air in the balloon got cold. Additional venting of the attic can help keep the house cooler but most important it keeps it dry.
2016-03-29 06:18:04 · answer #4 · answered by ? 4 · 0⤊ 0⤋
don't worry about it. the wires won't set your insulation on fire.
You're right about recessed lighting needing to be kept a certain distance from insulation, but they make a special type of can/recessed lighting to keep that from being an issue.
You can't find anything on it because it isn't a problem.
Very smart of you to ask, not enough people worry about fire safety when they remodel.
2007-01-20 09:00:19 · answer #5 · answered by badbadboy6979 4 · 0⤊ 0⤋
yes they do need to be derated if in or near thermal insulation for the exact figures check the IEE wiring regulations
2007-01-20 05:39:00 · answer #6 · answered by jonny w 3 · 0⤊ 0⤋
the insulation can go over the top of the cables
2007-01-20 07:26:09 · answer #7 · answered by aussie 6 · 0⤊ 0⤋