Garage Heater

[MoparNorm]

Your post does bother me a bit, please clarify, are the wires bare' IE are they laid loose and not in conduit, or are they in Romex?

The insulation on the wires is rated for 600 degrees, HOWEVER, wires should never be laid and left exposed! (Not in conduit)
It's not safe, not legal and rodents love to chew upon the insulation.
Please clarify.
Thanks!

[Gordon Maney]

I was assuming Romex.

[DrPepper]

how old is this house...???

if it was built in the 40's and has knob and tube holding the wires up, then you have a problem. Any houses built after the 60's - 70's should be wired by the NEC (Natl Electrical Code) and the wire guage will be more than adaquate to handle it's load without getting hot. That said, Gordon is correct in asking if there is a question about the installation. Insulation will not melt unless someone takes a (for example) 15Amp / 14ga. circuit, puts a 30 Amp breaker on one end and way to much load on the other, that will fry the circuit and could burn down the house.

Bundles of 10 - 12 individual insulated wires going thru holes in wall studs is a no-no, individual wire gets pulled thru metal conduit. Romex (depending on the state and local codes) is made to comply with NEC and can be run thru a wall cavity. Today most codes require a metal plate at each stud so you can't run a drill thru thr Romex. Sized correctly and with proper breaker size and use Romex works fine.

What you may find with your insulation is the chopped insulation can bridge on the wire and fill the cavity but not the bottom under the wire. It's OK, I go by the 90% rule or diminishing returns. You will love having an insulated garage. We are going to have -15F and 20+ mph wind tonight, this is Illinois??? For here that is stupid cold. Gonna' be a lot of frozen pipes tomorrow.
DrPepper

[Matt Wilson]

The house was built in 1984. I don't know for sure whether the wiring was installed in accordance with 1984 code or not, but I have to assume it was. ALL of the electrical wiring is running all over the attic, just laying on top of the ceiling joists, not in conduit, but it is all Romex, and appears to be the proper gage. It also appears to be connected to properly sized outlets, switches and circuit breakers. The Romex cables are bundled only in the attic, not in the walls. What is in the walls is also not in conduit.

I also laid down some new Romex cable in the attic in order to add increased service in the garage. It is all installed with proper wire gage, receptacle sizing, circuit breakers, no double-tapped neutrals at the panel, etc, but it is merely laid on top of joists, just as the old wiring was. Although I used quite a few plastic staples to secure it to joists, whereas the old wiring used metal staples, but very few. My newly added wiring is more secure in that regard.

I have read that bundles of cables tend to generate more heat than a single cable (makes sense), but I wasn't sure if it was a problem that these bundles are now covered by blown insulation. The biggest bundle of wires is the one that comes straight from the service panel, and looking at the panel with its cover removed, it may have a couple dozen runs of cable coming from it and into the attic, much of which remains "bundled" together for some distance in the attic. I put quotes around the word "bundled" because it is so loose, it is not really a bundle, but more of a bunch of side-by-side runs all located within several inches of each other.

[DrPepper]

Like the song says....

"...don't think twice, it's all right...". Your house technically doesn't even have lead paint to deal with. You probably have double pane windows and unless the local building inspector was a real crook, your wiring is up to code. The Romex laying all over the place while not "nice and neat" isn't going to be a problem and probably met local code when installed. Unless you need to find a particular wire for some reason and move it the wire staples don't really do anything either. Enjoy a great job, well done.
That's my $.02 with a song to boot...!
DrPepper

[Matt Wilson]

That sounds good to me, Dr Pepper.

Just FYI, I went ahead and did a Google search this evening and found several other forums where the same question had been raised, and even one or two articles talking this. The consensus (with only a small handful of people disagreeing - and no strong basis for their positions) was that insulating over Romex is not a problem.

Thanks again to everyone. I appreciate everyone's responses here. I often like coming here to the Power Wagon community, since there is a lot of knowledge and there are a lot of good folks here.

P.S. To keep this somewhat on the Power Wagon topic: I'm doing all of this upgrade work to the garage so I'll have a better-lighted and more comfortable place where I can work on my '49 Power Wagon. I've got a LOT of work to do to it, and I want to do it without either freezing in the winter or burning up in the summer. I must be getting old.....