Replies

1. 
   Aaron | Jan 11, 2007 05:18pm | #1

   I am not sure that I have seen what you are talking about, but I have installed plenty of lights powered by K&T.  Basically, the wires are just sticking out of the ceiling (or wall, for sconces).  Depending on how the condition of the insulation, I might wrap the wires with electric tape.  Then I would install one of those straps that should have come with the light fixture straight to the ceiling using drywall screws into the lathe.  I have also used what I think they call a spider, which is basically a three legged strap that is screwed to the wall and has a threaded center hole for a post.  Lights usually either install on a threaded center post, or on two threaded screws that go through the base.  I make the connections using the plastic connectors, and wrap them with electric tape, and go about an inch onto the wires.  Ground wire is just left in the housing attached to the fixture.  Then I place the housing through the center post or threaded screws, making sure that the wires are inside the housing.  Then screw the nut(s) onto the post or screws, and you are basically done.

   The only problem I have ever had is due to someone cutting the K&T too short, or the insulation would be coming off almost to the ceiling.  Usually, there is enough slack that you can carefully pull some wire down.  If that did not work, you might have to drill a 4 inch hole to put in a box, but I have never had trouble with the way I described above.

   Aaron

1. 
   cap | Jan 11, 2007 08:48pm | #2

   Aaron,You've "installed plenty of lights powered by K&T"? Your profile implies you're not doing it for hire. I hope it's just been in your house. As someone who's in "law/legal services" you probably know that doing substandard work for hire, or even for others w/o pay, exposes you to serious liability.Substandard work? Oh yea, what you've done and are recommending is clearly in violation of safe installation practices as spelled out in the NEC. And if the NEC is the operative building code in your area, by not installing a fixture box, you're violating the law, and more importantly, safe wiring practices.Why? Any splice between conductors of modern wiring methods has to be enclosed in a box (section 300-15(a) of the 1999 NEC). And the connection 'tween the fixture wires and the building wiring is a splice. This requirement for a box also applies to knob and tube wiring: "a box shall be installed at each outlet and switch point for concealed knob-an-tube wiring". A light fixture is connected to the wiring via a lighting outlet; the requirement applies to both receptacle and lighting outlets.The idea behind containing splices in a box is to protect the connections from damage, and to protect the building from fire if the connections go bad (overheats or sparks/arcs). Of course, if the splices are in a box, they're less likely to be damaged. But a poorly made splice can, even if protected, fail and overheat or throw sparks. not a good thing to have happen inside a wall.Of course, the old fixture can stay installed, sans box, till the end of time, and there's no violation of Code. But if you remove the fixture and install a new one, you have to install a fixture box to comply with the NEC.In addition, a Code requirement and safe practice you may have violated by connecting the new fixture wires to the K&T wires is that all materials be installed in accordance with their UL or other listing. Every modern incandescent light fixture I've ever seen has had a sticker on it (or in the installation instructions) saying that it must be connected to building wiring that's 90 degree C rated. That's because of the heat developed by the lamp in the fixture; that heat will likely degrade the insulation on old wire. Failed insulation could lead to a short circuit and a fire.The way around this with K&T or pre-90C cable or wire is to install a junction box a foot or two back of the fixture box and run modern cable to the fixture box. Yes, what a PITA. More critical for a surface-mounted ceiling fixture than for a sconce, to be sure. Sometimes there isn't access to install a j-box. Then it meets the letter of the Code to use short pigtails of 90C wire in the fixture box between the old wires and fixture wires. In that instance, I usually put heat-shrink insulation on the old wires. But if a j-box can be installed, why not do the job right?BTW, Arlington Industries makes a great little fixture box (of PVC) called a sconce box, in an old work style, which works great for K&T retrofits. The Arlington sconce box is especially good when the sconce has a small base.I think the requirement for a box is important, and ought to be followed even if it's your own house you're working on. After all, eventually the house is going to change hands. Subsequent owners have a right to expect any work done on the house to have been done right. Hey, come to think of it, your family does too.Cliff

   Edited 1/11/2007 12:54 pm ET by CAP

1. 
   Aaron | Jan 11, 2007 11:23pm | #3

   Cliff, I don't disagree with what you said generally, but I would disagree with your point that reinstallation of a fixture in the manner described is dangerous.  In many cases, the reinstallation of a fixture using wire nuts and after inspection, and if necessary, the repair of the existing insulation is safer than the original connection, which in many cases was covered with just tape.  Granted, the NEC states otherwise for new work, but my sense in discussing this with licensed electricians is that the way I described is not only safe, but is in fact how they would complete the installation.

1. 
   cap | Jan 12, 2007 01:51am | #4

   Aaron,I see your point, the new splices might be an improvement over the old ones. But having a splice outside of a box is bad (except for K&T splices done in the old style--splice supported by knobs w/in a foot on either side, western union wrap, solder, rubber tape, friction tape.)How bad? Burn-the-house-down-for-sure bad? Certainly not. But not safe, and not Code-compliant.Connecting fixture wires to building wires sans j-box is similar to splicing two building wires in a wall without a j-box; it's a "flying splice". Most everyone who's ever weighed in on that subject on this forum (and a few professional electrician's forums as well) agrees that any new splice of (line voltage) wires has to be a j-box. O.K., granted, the current in a fixture wire splice is going to be much lower than it could be in a branch circuit wiring splice; but the Code doesn't give you dispensation to skip the box.BTW, San Francisco electrical code explicitly allows existing K&T circuits to be extended via K&T; this because in a lot of old houses there there's no easy way to extend K&T, while having an accessible j-box in which to splice the transition to cable. So, it's not just the cable cars that are an anachronism in S.F. The Williamsburg of the electrical trade...see living history.Anyway, the licensed electricians you know who've installed a fixture w/o a box are either mis-informed about Code requirements, or are aware and are just cutting corners. I really can't understand why anyone with a professional (and legal) responsibility to a client would do that. Sure, the chances of a problem are slim, but it's not a big deal to cut in a 3R old work fixture box; a carbide-tooth hole saw will do the trick, and even in old wooden lath and plaster will not produce collateral damage.Cliff

2. 
   DonCanDo | Jan 12, 2007 02:07am | #5

   I spoke with the HO today and told her that in order to install new fixtures we need to call in an electrician.  I know an electrician who's worked with plenty of K&T and we work well together.  She doesn't want to spend any more on fixing up this basement room so she will live with the old fixtures.

   But I'm still curious about this "bracket" for the old fixtures and how it's mounted.

   -Don