New Fixture, Old Wiring

Status
Not open for further replies.
J

jeff43222

Senior Member
Location
Minneapolis, Minnesota
I have a homeowner who wants me to replace three sconces in the upstairs bedrooms of a two-story house built in the 1920s. I went in and looked at the situation, and I discovered that the existing sconces are quite old, possibly original with the house. They are screwed directly into the wall (plaster/lath) and fed with K&T. None of the sconces have boxes behind them.

Most of the lights I've installed lately have instructions that say the light must be grounded. My feeling is that 110.3(B) prohibits me from installing a new light fixture with the old wiring if the light fixture instructions call for grounding.

Anyone disagree with my interpretation?
 
An alternative is to run a separate #14 wire to a known electrical ground.

Hint: A wiggie and an extension cord can help identify the hot and neutral.
 
If I'm going to go to the trouble of running new wiring for a ground, I might as well go all the way and run new grounded/ungrounded conductors to get rid of the K&T. But doing that would be fairly difficult with the layout of the walls and ceilings. Overall, I think the homeowner would be happier with newer wiring (she's most interested in safety), but it would be time-consuming to install it.

I deal with K&T quite often, and I have found my Fluke hot stick does a pretty good job identifying the hot vs the neutral.
 
But then don't forget about that 90degC wire referred to in the instructions. It's the biggest curse when trying to install new light fixtures often overlooked because it is impossible to comply with without replacing the wiring to the box itself. And it appears to be taboo to talk about because no one wants to hears what the correct answer is including myself.What are you going to tell someone that they have K&T wiring or TW wiring that is not rated 90degC and that it's going to cost them more to bring the box up to 90degC, that it would cost more to do that than the cost of the light fixture.
It's a difficult subject for electrician who are know for their passion of following the letter of the law (NEC).
 
jeff43222,
If that Fluke "hot stick" is like a yellow and gray pencil where the tip lights up red when placed close to an energized conductor I have one and it's the greatest thing since sliced bread.
As with any instrument it should be used with caution. I always check mine against a known energized conductor to assure that it is working, check the wire in question, then recheck against the know energized conductor to assure that it is still working.
Meters should actually be used in the same way but most of us don't verify that they are operating correctly including me.
Dave T
 
Jeff,
In the early 90's I rehabed a lot of houses in cleveland. We were allowed to either cut in a box or install pan cake boxes. Talk to your AHJ. :D
 
Jeff you are in a tough position. What good what a box do for K&T? I believe there are some sconces made that do not have grounding requirements. Put a GFCI breaker on the circuit or decline the job.

Hank
 
Re: New Fixture, Old Wiring

jeff43222 said:
My feeling is that 110.3(B) prohibits me from installing a new light fixture with the old wiring if the light fixture instructions call for grounding.
Click to expand...

I think you can forget 110.3(B) and just go with 410.18(B)

410.18 Exposed Luminaire (Fixture) Parts.

(B) Made of Insulating Material. Luminaires (fixtures) directly wired or attached to outlets supplied by a wiring method that does not provide a ready means for grounding shall be made of insulating material and shall have no exposed conductive parts.

Exception: Replacement luminaires (fixtures) shall be permitted to connect an equipment grounding conductor from the outlet in compliance with 250.130(C). The luminaire (fixture) shall then be grounded in accordance with 410.18(A).
Click to expand...

In my opinion unless these new lights are made of insulating material your only choices are either install a grounding means or walkaway from the job.
 
Usually the only time I see the 90 degree requirement is when it's a light fixture that is flush-mounted and has a sealed globe. This make sense since the heat from the incandescent bulbs has only one place to go: right up into the box. I often find fried insulation when I open up such fixtures. Personally, I don't think this kind of light fixture should even be legal, but it's not up to me. I do insist on the 90 degree conductors when I have a homeowner who wants me to install that kind of light. I haven't seen a sconce with the 90 degree requirement; the bulb is usually positioned such that it won't heat up the box.

templdl: I agree that the Fluke hot stick is one of the best things since sliced bread. I use mine all the time. And I always test my tester before I use it.

chicar: This week I'm going to be meeting with an inspector for another job I'm doing. I'll take your suggestion and see what his take is.

But I suspect Bob is right. Either the light has to be insulated, or it has to be grounded. I don't think the code allows for substituting GFCI protection in place of the ground in this case. Either way, I need to install boxes.
 
I would like to see a ceiling mount light fixture that does not require 90C wire. Even pendants have the requirement.
 
Hey Jeff,

My experience with local inspection, til last Fall, has been that 250.110(1) provides the exception for grounding. If the existing sconce is within five feet horizontally and/or eight feet vertical of a radiator, its piping, hot air ducts, or other grounded surfaces exposed in the room, then the new sconce must have an egc provided. Otherwise, the only thing necessary is to cut in a box. The type of j-box is dictated by the framing and wall surface.
 
Hi Al,

Has your experience been any different now that we are under a new AHJ?

250.112(J) appears to require grounding of luminaires. I then looked more closely at 410.18, and I found that with the 2005 edition 410.18(B) Ex. 2 says that I can put in GFCI protection in this case without having to run an EGC.

I think putting in GFCI breakers might be cheaper than having to run new wiring.
 
jeff43222 said:
Has your experience been any different now that we are under a new AHJ?
Click to expand...
I haven't had the opportunity to ask the question yet.
 
Here's an update:

I went over to the house today and looked at the sconce lights the homeowner wanted me to install. I thought they would be a good choice for the type of installation, until I noticed the sticker inside that said the fixture required minimum 90 degree conductors. Unfortunately, the exisiting wiring is K&T, which (I'm guessing) isn't up to the 90 degree standard.

What I found odd was that the fixture called for 90 degree conductors. I generally only find that requirement on flush-mounted fixtures with a sealed globe/shade, as that would have all the heat from the bulbs dissipating through the outlet box. But today, the fixtures were sconces with the bulbs in the open, and the heat from the bulbs wouldn't really have much effect (in my opinion) on the wiring behind the plate.

Of course, I have to follow 110.3(B), but I wonder why this kind of fixture would call for 90 degree conductors. I had to send the homeowner on another quest for suitable fixtures. (Re-wiring would be cost-prohibitive).
 
I'm going to be deliberately stupid for a minute (at 6 AM what else could I be). The instructions that come with the lights say to use 60C supply wires. What if I pigtail 90C wires to the existing wires and attach the pigtails to the fixture? Have I complied with the instructions. Is the "supply" back to the last JB? The last OCPD? The service? The PoCo?

Mark
 
busman said:
What if I pigtail 90C wires to the existing wires and attach the pigtails to the fixture?
Click to expand...
Heh! :)

Great question and turn of the language.

The language on the luminaire label seems to say that the fixture wires are the items that are hot. . . .
 
Status
Not open for further replies.
Top