temperature rating on electrical wire


  #1  
Old 03-08-03, 07:31 PM
mhaystead
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temperature rating on electrical wire

I am replacing two lights in my bathroom. There is a warning label enclosed to make sure the wiring is rated for 90 celsius, the note says that most homes built before 1985 used 60 celsius rated wiring. Is there anyway I can tell by looking at the wire? My home was built before 1970.
 
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Old 03-08-03, 07:39 PM
J
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There are some ways to tell, but it's probably not worth the trouble, because you do not have 90-degree wire. Sorry.

The two main options at this point (neither very good options) are: (1) Take the fixtures back and find ones that do not require the warning. Such fixtures do exist, but can be pretty hard to find. Look for fixtures that hold the bulbs away from the wall or ceiling, or for fixtures that use fluorescent lights. (2) install a new electrical box a foot or two away from the other box. Use the box to patch in a new section of NM-B wire (that is 90-degree rated). The box with the splice must be covered with a blank cover and remain permanently accessible.
 
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Old 03-09-03, 08:28 AM
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I have a few of those fixtures installed in my home that was built in 1980. From what I have found out the heat will cause the wire to deteriate over the years. From the information I put together I have decided for me that the risk is very low. I use smaller watt bulb then the Max and their in the hallway where the do not stay on very long. I will check the wires on an annual basis and someday when Im in the attic will install a box with the new wire. This has been discussed in the past many times. Do a search and learn a little more. I am not an electrician and I am not saying you should use them, just giving you another opinion so you can make your own decision. Hope this helps.
 
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Old 03-09-03, 05:19 PM
lestrician
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Even though Michael may be correct, if you ever have people over who may possibly leave the lights on longer, or if you go to sell you house.... this can cause problems. Yes, it's been discussed here often, and with good reason. Too many fires are started by not adhering to instructions.
 
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Old 03-23-03, 04:09 PM
mhaystead
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I found out that my wife's stepfather had replaced the fixtures in the early to mid 80's. The wiring he ran appears to be some kind of Romex with NM printed on it. It looks identical to Romex I have bought in the last few years. I have looked at the wiring in the breaker panel and it appears that everything branches off of junction boxes in the attic or crawlspace, since the bathroom circuit is shared with outlets in a couple other rooms. At some point I would like to have each room dedicated to its own circuit for easier identification, but I don't think I'll do it until a major remodel of the house.
 
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Old 03-23-03, 04:57 PM
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A lot of times it isnt really identification that becomes the problem. It may be grounding or hi usage. Before they had all these hair dryers and such, the thing for the bath was a razor and things were not so power hungry. Some rooms are ok being on with other things, normally bedrooms dont use much unless vaccuming, but baths these days are different. That would be a place to run a new circuit to, and kitchen counters. I also kind of like a wire direct for hi draw stuff and not thru some old junction boxes. Again, not so critical with electric clock or radios or tv like in bedrooms where the power draw is low.
 
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Old 03-23-03, 05:31 PM
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For reference, Romex is a manufacturers model name for non-metalic cable (NM).
If it is stamped NM-B then it is 90 degree rated.
 
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Old 04-12-03, 12:42 PM
mhaystead
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I decided to rewire the bathroom fixtures to the existing junction box feed in the attic. The original switches were a double light switch and a combo switch receptacle in a double gang metal box.

I removed the existing box to install a deeper old work plastic box. I chose to replace the existing switches with a GFCI and a single decora triple rocker switch unit.

When I removed and traced the existing wiring, I discovered that the switch was fed by BX cable coming from the bathroom hall light (all ceiling lights are on one circuit). Another BX cable was going out of the wall box to a junction adjacent to one of the two bath ceiling lights. A Romex style NM cable was also going out to this junction. The hot was feeding the combo switch and pigtailed to one side of the double switch. The NM cable was on the other side of the double switch. The other BX cable was on the other side of the combo switch.

One of the switches went to a light fixture over the sinks, the second went to two ceiling mounted lights, and the third went to two exhaust fans (originally the bathroom only had one ceiling light and fan).

I chose to bring a single #14 NM-B cable as a feed into the new box. I then ran three #14 NM-B cables into the box for each switched circuit (fed directly to each device). I pigtailed all of the neutrals to the neutral side of the new GFCI receptacle. I pigtailed all of the grounds to the GFCI ground. Finally, I wired the feed hot to the GFCI with a pigtail to the triple rocker switch common terminal. I then wired each hot to the one of the three load terminals.

When I put it all into the box, it seemed a little crowded. Have I exceeded any restrictions doing it this way? Would it have been better to run two #14 NM-B cables to the triple rocker instead of three?
 
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Old 04-12-03, 01:08 PM
mhaystead
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Correction to previous reply, I noticed the NM-B is stamped 12-2, I thought it was 14-2.
 
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Old 04-12-03, 02:16 PM
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This only needs 26 cubic inches to be legal. My guess is that your plastic double-gang box is at least this big. You didn't mention grounding the triple-switch, but do that too. Then you'll be fine. Perhaps it only seems crowded because you did not do a neat enough job of folding the wires back into the box.
 
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Old 04-24-03, 12:37 AM
marktanglewood
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60 or 90 Celsius with Aluminum Wiring!?

OK, so I read all previous...

My scenario: Built 1978, aluminum wiring (Houston, TX)

Trying to UPGRADE all original lighting fixtures to something that is comparable to the neighborhood MARKET value/style: but ALMOST ALL FIXTURES that I try to install ask for 90 degree Celsius wiring! (the box doesn't always state such on the outside!! dang it! and now i have 10 fixtures to return!!! DOH!).

Cannot find a "Romex" stamp anywhere since it is a condominium and don't have attic or basement access--don't really wanna tear into the walls... <sigh>

AND... I am selling my place: don't want any liability!

ANY HELP GREATLY APPRECIATED!
 
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Old 04-24-03, 06:03 AM
marako
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Let me get in trouble by throwing these thoughts out:

First I would bet that there is absolutely no difference between light fixtures today, vs those built 20,30,40+ years ago. Those fixtures needed 90 degree wire.... they just didn't realize it then. So I don't worry when I see "use 90 degree wire" since that is probably there to cover the manufactures a-- or a UL requirement. Actually I'll retract a bit... todays fixtures are probably better built for heat disapation than those from years ago.

It takes a long time for the heat to destroy the wire.. probably decades (my guess). We've all pulled down old fixtures and had the insulation fall apart though I've only really seen that with the really old cloth wires, not really the newer plastic covere wires.

No house inspector I've ever seen pulls the fixtures off the walls/ceilings to check wiring so reselling the house shouldn't be a problem.

If really worried get yourself a short length of NM-B and either replace the existing pigtail with this new wire, or add a pigtail to the exiting wire if it just comes into the box directly to the fixture. The place with the most heat should be near the connection point. Put in some compact flourescent bulbs then heat will never be an issue.

The point I'm making is that you'll have a tough time finding 60 degree labeled fixtures (if you can), and if you leave up the old fixtures guess what..... they also need 90 degree wiring so you can't win.

For the guy with AL wiring I'm not sure what to do. You can go to a supply house and see if you can get some 90 degree 12 gauge AL wire and relace the pigtails, or extend the wire as I mentioned above. Make sure that all wirenuts etc. are rated for AL wiring. Not sure if you need to use NOALOX in this case.
 
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Old 04-24-03, 06:08 AM
J
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If you can find fixture with the bulbs away from the ceiling they should be 60 degree rated. An extreme example would be a chandlier. The problem comes when the bulbs right against the ceiling. Flourescent fixtures would also work.
 
  #14  
Old 04-24-03, 11:51 AM
marktanglewood
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Thumbs up Aluminum wire connectors and 90 Celsius rating

Great responses, all logical... I think I will make one more trip to the store to find a fixture WITHOUT the 90 Celsius warning... I think you are right, Marako, most are now 90 Celsius rated.

As far as Aluminum Connectors:

"Ideal Twister Al/Cu Wire Connector, model #30-765" comes with the anti-oxidant compound already inside of the connector--very cool. They are purple in color and usually on the top shelf hidden away from the rest of the red, yellow and green connectors.
 
 

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