But it’s not always that simple, especially if you have a home built before the mid-1980s and buy a recessed light, only to discover a warning on the back: “Fire Hazard. Most homes built before 1985 have a 60 degree rated supply wire. [Celsius]. Consult a qualified electrician before installation.
The problem is that earlier wiring was designed to withstand temperatures up to 140 degrees Fahrenheit, the equivalent of 60 degrees Celsius. A fixture fitted with bulbs near the ceiling can get much hotter, especially when high wattage incandescent bulbs are used in an enclosed fixture. Heat degrades the insulation wrapped around each of the wires in the cable, making it brittle and friable, greatly increasing the risk of fire. So newer wiring is designed to last even at 90 degrees Celsius (194 degrees Fahrenheit).
If you’re not sure what kind of wiring you have, check the attic, assuming the device you want to replace is on the top floor. If the cable feeding this ceiling box is insulated in fabric, that is the old standard. If the wiring cables are encased in plastic and are stamped “Type NM”, for non-metallic, they are also made to the old standard. If it says “Type NM-B”, it meets the new standard.
If you have old-fashioned wiring or you don’t know how old the wiring is and it’s not easy to check, you might think the easiest solution would be to use LED bulbs, which stay cooler than incandescent bulbs. But later occupants might not realize the need to use cool bulbs.
To avoid future hassles and the risk of fire, have an electrician install a junction box at least three feet from the ceiling box and terminate the old wiring there, with a short length of wiring of type NM-B to the ceiling box. You don’t need to replace the wiring further from the ceiling light, because those areas won’t receive such intense heat. But where there is no attic above, adding the new box will involve cutting and patching the ceiling.
If you don’t want to retrofit the wiring near the light, there are plenty of other options, but they all start with returning the fixture that has the warning. If you need a fixture that fits your ceiling perfectly, you can get a “maintenance-free” recessed fixture with non-replaceable LED bulbs. When the bulbs go out, you replace the fixture; it’s unnecessary but safe, and it’s also cheaper than hiring an electrician and fixing the ceiling. You can also get a fixture that takes a circular LED bulb or a screw-in style that doesn’t exist in incandescent bulbs, eliminating the possibility that someone could switch to an overheating bulb.
If you don’t need a recessed light, you can probably avoid the wiring problem altogether. Semi-flush fixtures, which hang about four to six inches, have a greater ability to disperse heat from the bulbs, especially if the bulbs are only shielded underneath or not at all, rather than being enclosed . Chandeliers radiate heat even better.
Aside from the wiring issue, there are a few key factors that can complicate a ceiling light replacement. Save on trips to the hardware store by inspecting your old device before shopping. You will need to shut off your power at the circuit breaker and loosen the base enough to see how it is attached. Some fixtures have a ring with curved slots, and others have a bar or pair of bars that form an X. Some depend on a threaded rod that hangs down the center. Try to find a replacement light that uses the same mounting system or has mounting hardware that would be easy to install on your ceiling box. Also consider the weight of new and old devices. If the new one weighs more than 50 pounds, you may need to replace the ceiling box with one designed for ceiling fans.
When you go to install the new fixture, replace the mounting hardware, if necessary. Make a temporary hook from a metal coat hanger by using pliers to cut the angled wire from one side and shorten the other side to about 10 inches. Fold this end into a hook. Then you can hook the bracket to the mounting hardware and use the hook to hold the base of the new fixture close to the ceiling while you attach the wires.
Unless you have a metal ceiling box connected to a ground wire (bare copper, usually held on by a green screw), secure the bare wire from the fixture to the mounting hardware using the special green screw designed for this purpose. (A typical wood screw will not hold the wire securely enough.) Next, attach the fixture’s live and neutral wires as instructed in its instructions.
The device wires will likely be stranded – a bundle of thin wires wrapped in insulation. Use a wire stripper to cut back about ¾ inch of insulation. House wiring is probably solid, thicker wire. It should be stripped ½ inch, so trim the wire or trim the insulation as needed to achieve this length. By hand, wrap the stranded wires tightly around the solid wire, then twist a wire nut until the connection is tight.
Once the wires are connected, carefully bend the excess wiring so that it fits into the ceiling box. From there, it should be simple: Install the base, add the bulbs if needed, and put on the lampshade if there is one. Restore power, then turn on the light.