I bought a light fixture that has a min 90°C warning. The wiring leading up to the fixture is NM (60°C wire). I was wondering if an easy workaround to this would be to install a newer, more energy efficient light bulb to keep the temperature of the wire down.

Is this a viable solution to this problem? The next option is to replace the last 2 feet of NM with wiring that is certified to 90°C.

  • 1
    Are you sure you mean "minimum" 90C? – The Evil Greebo Oct 25 '12 at 14:06
  • Yes, its right on the box.. "MIN 90 C SUPPLY CONDUCTORS" – tyler Oct 25 '12 at 15:53
  • Are your sure you have 60°C wire? My admittedly outdated reference for Type NM cable under Construction Specifications, says essentially that conductors shall be rated 90°C but the allowed current shall be as for 60°C conductors. – bcworkz Oct 26 '12 at 3:33
  • I was under the impression that NM is 60°C and NM-B is 90°C – tyler Oct 26 '12 at 14:33

That's not a good workaround. Recessed Insulation Contact (IC) lighting fixtures have a target temperature of 90ºC in the junction box. Kinda crazy, but that's what it is. See NEMA Bulletin #92 (December 2005) which reads:

When the dwelling’s existing wiring is rated 60ºC, install a junction box approximately 18 inches away from the newly installed lighting fixture and then run Type NM-B from the junction box to the fixture.

Installing the energy efficient bulb will not meet code. You'll be fine. But how are you going to prevent the next owner from sticking a hefty bulb in there?

An alternative is to take that fixture back, find something with a GU-24 socket, and hope the vendor was smart enough to realize that GU-24 means lower heat.

  • My thoughts exactly wrt the next person.. – tyler Oct 28 '12 at 3:10

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