Outlet above a fireplace for TV.

[kspousta]

tl;dr - How would you tackle the installation of an outlet above a fireplace?

I've been a lurker for years and have usually found the answer to my question(s) just by searching, but I'm coming up just a little short this time around and could use some help. I am not an electrician, but was a contractor for many years.

I hired a contractor to install a new fireplace (gas fired unit) in my home. After 3 days, I fired them because their work was atrocious. Nothing square, plumb or level and they missed several critical heat clearances that were clearly defined in the install docs. I've torn out everything they did and rebuilt it properly and am almost ready for mechanical inspection.

The design calls for a TV to be hung on the wall above the fireplace and as such, I need to get an outlet up into that area. (see attached pics)

The previous installation had outlets in the face of the hearth and I removed those and pulled the wire back, ran it up the wall and poked it through the king and trimmers where you can see it at the right side of the popout opening. I'd like to place the outlet about 16" to the left of where the wire comes through the framing, but I'm concerned about heat generated by the fireplace once this is all closed off.

I initially contacted a local electrical firm who normally does large commercial jobs to see if they would help me figure this out or, just come out and do the work (I know time is valuable). I sent them pics and had a couple phone calls with them and they've gone dark. No contact for over a week so I assume they're not interested.

I popped in here to start reading and found several threads and some good info on where to look for a solution:

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High-Temp Building Wire?

I was reading a manual for a commercial kitchen ventilation hood and came across this warning: All field wiring on top of the hood must use high temp wire and wire nuts (black). Wiring must be routed through hard or flex conduit. Route and attach all conduit on top of, or above, structural...

forums.mikeholt.com

Between those threads and reading the NEC, I *think* I have a basic path forward, but I'm having a tough time just sourcing the Type-Z wire. I've reached out to several wire manufacturers, (Southwire, Allied, etc) and they've all basically told me they can't help me and to try my local home improvement store or online electrical supply houses. Of course, Home Depot etc doesn't carry anything high-temp and the online outfits all want me to buy 100+ foot spools. Where can one find a 25' coil of this stuff?

I have wire on hand (14 AWG, Silicone, 7 strand tinned copper, 200C rating stamped on the jacket) but it doesn't meet NECs marking provisions so I'm hesitant to use it. Assuming I can find a short piece of Type-Z, I'm looking at the black Gardner Bender hi-temp wire nuts (GB-4s?) and high-temp crimp on terminals and am planning on using a metal J-box and either EMT or flexible conduit. Not sure which way to go with the outlet itself though as I haven't found any temp ratings for the units I have on hand - I'm not averse to buying a different outlet. The only load on this circuit will be the fireplace itself, the TV, a cable box, a Bluray player and *maybe* a soundbar. Looks like a tick over 7A total based on the labels on the gear.

The framing above the fireplace will all be steel stud and insulated with 3.5" mineral wool batts and I was going to 'sandwich' the conduit and box with those batts.
There *are* two 3" outside air ducts entering this space and I *may* put small fans (110V@20W) on them to force air in, but currently it's set up for convection only.

Am I on the right path or do I need to keep reading?

Thx!

 

[hbiss]

This thread will probably be closed because we don't give advice to DIYs. But that is an interesting fireplace. I, at least, have never seen one with outlets for external registers like that. I would like to know what the internal temperature is going to be in that chase. That said, your search for high temperature "wire" isn't going to help you, those are individual conductors. You will be using a cable. Your normal Romex can be used up to 90 deg C (194 F). It gets used in attics all the time. I wouldn't want that to get any hotter in there.

I suggest you contact another electrician and this time don't tell him how to do the job.

-Hal

 

[kspousta]

I suggest you contact another electrician and this time don't tell him how to do the job.

No idea how you assumed I told anyone how to do their job. I explained the situation and asked for help or if they just wanted to come take care of it.

Also no idea where you got the idea there were 'outlets for external registers'. It's a single outlet for a TV.

I don't know how hot it will get in that space once it's all closed up, hence the questions regarding high-temp solutions. If I had to guess, based on temps of the direct vent pipe and the corrugated heat transfer ducts and the top of the unit after 30 minutes of running on high, North of 200F (which is why I don't want to use the existing Romex.)

It's all moot at this point since I likely won't be finding any answers here.

 

[Mr. Serious]

You're looking for an engineering solution to a problem not routinely faced by electrical contractors. So, your guess is as good as anyone's. Appliance stores might have high-temperature wire, because you would normally find it inside heaters and other appliances. But even if you use wire rated for high temperature, you're still putting the receptacle and whatever plugs into it under more stress than usual, if the wire will be that warm.

Why not surface-mount the electrical installation on the outside of the wall after it's closed up? Or fur out the wall some more, essentially creating another wall space that won't have such high temperatures.

Also consider that copper wire conducts heat very well, so if the length in the hot location is short, heat will be transferred and radiated further out along the length of the wire, keeping the wire in the hot location cooler than its surroundings.

 

[tthh]

Few things...

The previous poster's comment "I...have never seen one with outlets for external registers" is referring to the 6 ducts coming off the fireplace insert. His assumption is these are attached to some blower that is circulating around the firebox and sending that hot air to some other places in the room.

If you are worried about temperature, the flexible conduit in your photo is rated for 122^oF if I am not mistaken.

I would bet the installation manual for the fireplace has a lot of useful information in it as to clearances and such.

 

[hbiss]

I don't know how hot it will get in that space once it's all closed up, hence the questions regarding high-temp solutions. If I had to guess, based on temps of the direct vent pipe and the corrugated heat transfer ducts and the top of the unit after 30 minutes of running on high, North of 200F

Yes, the hot air ducts and the uninsulated flu as well as heat from the top of the unit.
I don't think I would want a space like that to be that hot. Anybody know at what temperature pyrolysis of wood starts to occur?

-Hal