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Installing an old-work electrical box in an existing ceiling (C) Daniel FriedmanCeiling-Hung Light Fixture Installation
Steps to fix or replace a light fixture suspended from a ceiling-mounted electrical box

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How to install a ceiling light fixture:

In this article we use an "old work" electrical box to replace the damaged box, secure the new box and re-mount the light fixture safely.

We discuss the requirement for secure mounting of ceiling electrical boxes for fans and lights and we give step by step details for installing a replacement electrical box, insulating around it, connecting the ceiling light wires, and then testing and completing the installation.

The electrical box repair or replacement procedures described in this article series describes step by step repairs for both metal and plastic electrical boxes used in building electrical wiring systems.



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How to Fix or Replace a Loose, Damaged Ceiling Light Fixture Box

Bath ceiling light after new installation (C) Daniel FriedmanAbout a year after the light fixture shown at left was installed we observed that it was falling away from the ceiling!

Watch out: any loose electrical fixture is likely to involve a shock or fire hazard. It needs to be repaired.

The cause of the trouble, wrong type and broken mounts in a plastic electrical box used in the ceiling are discussed at the preceding article: PLASTIC ELECTRICAL BOX REPAIR.

Here we explain how to repair the falling ceiling light while avoiding having to disturb or cut open the ceiling by using a well-secured old-work electrical box designed to be inserted through a just-fit hole in a ceiling or wall.

[Click to enlarge any image]

The best repair for this hang-dog light fixture would be the insertion of an electrical box supported by a telescoping support bar that in turn is secured to the ceiling joists.

In this home, with spaced I-joist ceiling framing that was packed with sprayed-in insulation we wanted to try a simpler repair that would avoid having to hack out the insulation or rip down the ceiling to effect a reliable repair.

We reasoned that the particular light fixture is light-weight and that the failure of the original electrical box was not due to the weight of the light fixture, nor was it due to breakage of the ceiling drywall (though that could certainly happen if there were roof leaks from above).

We knew that the original installer had broken all of the swing clamps on the original old-work electrical box.

Shopping for a heavier old-work swing-clamp electrical box was an easy and tempting solution.

15 Easy Steps to Replace a Damaged Ceiling Light Fixture Box

Below are the detailed steps in the repair procedure for re-connecting and re-hanging the ceiling light fixture. In the short time of an ensuing five years the repair described below has performed without any sign of movement nor other trouble.

  1. Turn off electrical power and confirm that it is off where the electrical work is to be performed.

    See ELECTRICAL TOOLS & TESTS for using a neon tester, DMM, or VOM safely.
  2. Remove the light fixture and set it aside.
  3. Remove the broken electrical box and inspect it to understand the cause of damage and thus the need for repairs. Below I illustrate two of the three broken swing clamps.

    Broken old work electrical box swing clamps: Visual inspection of the broken swing clamps on the electrical box as it was exiting the ceiling showed one swing clamp broken off completely (below) and the other two cracked with broken-off parts. In short the swing clamps intended to hold the box in place had been destroyed during installation.

    At below left I've loosened the screw to examine it but when I first looked at this swing clamp the clamp body had been turned down tight against the plastic box stop just as were the other two - see below right.

    The swing clamp screws had been so tightened that they were askew in their mounts and the swing clamp screw passages were cracked.

    I had also observed that the swing clamp screws were so tight that I had difficulty loosening them: in my view there was ample evidence that they had been over-tightened.

    In PLASTIC ELECTRICAL BOX REPAIR - we claim that the over-tightening occurred during original installation of the oldwork box when the installer used a powerful high-torque electric drill to turn down the box mounting clamps. However in that article we also describe other field-observed old work box failiures from other causes.

Broken swing clamp on a plastic old work electrical box (C) Daniel Friedman Old work plastic electrical box swing clamp broken (C) Daniel Friedman

  1. Inspect the electrical wires for damage: removing and replacing electrical boxes risks cutting or nicking the electrical wire insulation - possibly creating a short circuit or fire hazard. Be sure that the wires to be re-used are un-damaged.
  2. Inspect the ceiling (or wall) cavity for damage, leaks or other things you'd wish you'd found before trying to shove the new electrical box into place. In this case it was apparent that the original installer had made his job easy by pulling out more ceiling insulation than was necessary.

    This gave plenty of room for wire manipulation but it also created a point of heat loss and a hot spot in the roof. We address the insulation voids around the new electrical box in a later step.

    Watch out: At this step you need to decide if a structural support for the electrical box is needed or not. Never install a ceiling fan nor a heavy light fixture in a ceiling without proper support: the result will be unsafe and may fall on someone's head.

Ceiling cavity ready for installation of an old work electrical box (C) Daniel Friedman

  1. Insert the electrical wires into the box: Push the electrical wires into the replacement electrical box through the appropriate wire clamps or openings.
  2. Insert the electrical box through the opening into the ceiling (or wall).

    Tip: Keep your hands clean and avoid making filthy smudges or wire gouges on the ceiling; if you work carefully and avoid unnecessary enlargement of the ceiling opening the ceiling light installation can be completed without having to re-paint the ceiling or repair drywall.

    Watch out: avoid kinking or damaging the electrical wires that must be pushed back into the ceiling or wall cavity as you insert the electrical box through its opening. I bend any extra wire length into a round curve that will coil in the open space without kinking.

Installing an old-work electrical box in an existing ceiling (C) Daniel Friedman Old work electrical box being inserted into the ceiling (C) Daniel Friedman

I've left one of the securing ears of the old work electrical box "out" for the photo at above left so that you can see it (below left, orange arrow).

But during installation the rotating ears or clips are pressed flat against the box sides as it is pushed through its mounting hole into the ceiling or wall cavity (below right, red arrow).

During installation of the old work box, its mounting screws (green arrows at above right) are turned causing the plastic ears (red arrow) to rotate open and then pull tight against the drywall or plaster ceiling or wall surfaces, pulling the old work electrical box flange against the exposed side of the ceiling or wall and holding it in place.

  1. Tighten the oldwork electrical box swing clamp screws.

    Watch out
    : if you insist on using a power-screwdriver or a drill-operated screw driver take great care to avoid over-tightening the swing clamp screws lest you crack the clamps, break them, or pull the clamp through a soft drywall surface.
  2. Insulate the building cavity around the electrical box: we used spray foam to fill the voids left around the old work electrical box after it was secure in the ceiling.

    I'm using a closed cell foam insulation that has the added benefit of essentially gluing the electrical box into the ceiling cavity by contact between the box exterior surfaces and the exposed upper surface of the drywall or of any framing reached by the insulating foam.

    At below left you will see that I've inserted my foam sprayer nozzle up through an un-used wire entry clamp in the electrical box so that I'm spraying it into the building cavity, not into the box.

    Watch out: you or your electrical inspector might prefer that you use fire-rated fire-block foam insulation in this application.
    See FIRE-BLOCK Fire Retardant Foam Spray Building Insulation

Insulating the ceiling cavity around the old-work electrical box installation (C) Daniel Friedman Insulating the ceiling cavity around the old-work electrical box installation (C) Daniel Friedman

I stopped squirting foam into the ceiling cavity when I saw it beginning to ooze out of an opening at the opposite side of the electrical box (below left), figuring that I'd probably filled the cavity. Then I waited to see how much foam was going to ooze into the interior of the electrical box itself.

At below right, peering around one of the wires penetrating the electrical box things looked just perfect: you want to foam-fill the building cavity but not the electrical box.

Foam insulation oozing out at the ceiling tells us when to stop  (C) Daniel Friedman Foam visible through the electrical box (C) Daniel Friedman

But wait, wait! Wait until the foam has fully cured and hardened. If you try fooling with the foam spray insulation before it has cured you'll find yourself in a horrible sticky gooey mess.

Don't do that. Here is what my "just perfect" foam insulation job looked like when the foam had fully hardened:

Foam around an electrical box after curing: time to remove excess foam (C) Daniel Friedman

  1. Remove excess foam that leaks into the electrical box. Despite working with care, spray foam will expand more than you expect and some is bound to ooze into the electrical box or out of any openings around the box. In fact if you do not see any ooze-out you probably didn't fill the building cavity with insulation.

    Wait for the foam to fully cure and harden, then working carefully to avoid nicking any wires, remove all of the excess foam that has oozed into your electrical box.

    Watch out: regardless of the type of foam insulation you squirt into the building cavity you do not want to pack the interior of the electrical box itself with foam. Besides the fire and heat issues, the foam will get in the way of wiring, wiring devices, or the pushing of device or fixture wires into the electrical box when the fixture is to be installed.

Using a table knife to remove foam from an electrical box (C) Daniel Friedman Plastic electrical box after cleaning out foam (C) Daniel Friedman

I used a stainless steel diner knife that has a rounded tip and no sharp edges to carefully loosen and remove the cured foam insulation. The object is to remove the foam (read "fire kindling") without damaging the electrical wires. The result, above right, is a box empty of foam that might contribute to overheating or to a fire and as well, the electrical wires as well as the box itself are quite securely bonded in place in the ceiling.

  1. Prepare the electrical box wires for connection to the light fixture: this includes bonding the circuit grounding conductor wires from the switch circuit and power circuit together. These wires will also be joined with a smaller copper ground wire connected to the light fixture.

Grounding wire crimp installed over the circuit grounds (C) Daniel Friedman Crimping the copper grounding conductor bonding connector (C) Daniel Friedman

Above we slip the copper crimping sleeve over the circuit ground wires; at above right we crimp the connector.

Below you can see the secured crimp connecting the circuit and switch grounding conductors. When the photo was taken that crimp was incomplete. The crimping tool used requires two passes to secure the metal crimping connector.

Watch out: don't try using lineman's pliers or wire cutting pliers to secure a metal wire crimp connector. You'll cut or nick the connector, it won't be properly squeezed, and the connection may be unsafe.

This plastic electrical box did not contain a grounding lug and as it's a plastic box there is no ground wire connected to the box itself.

Ground wires bonded together in the electrical box (C) Daniel Friedman Electrical wires at the electrical box ready for connection to the light fixture (C) Daniel Friedman

At above right I've arranged the white neutral wires and black hot wires and ground wire where it will be easy to connect them to the matching light fixture wires using twist-on connectors.

  1. Prepare the light fixture support bracket & wiring for installation. This includes attaching the ceiling light support bracket to the light fixture itself.

    At below left I'm using a pair of flat nose pliers to tighten the nut that attaches the suspended light fixture vertical riser tube to the rounded pendulum that permits the light to hang straight down even when installed on a sloped ceiling.

    A conventional socket and socket wrench won't work because it can't fit over the wires passing up through the riser tube.

    You'll notice I'm avoiding damage to the glass globe and shade by performing this work on a nearby quilt-covered couch and with the assistance of Mini and Fala, a pair of stuffed animals.

    At below right the light fixture support bracket, wires, and screws are in place and ready for the fixture to be lifted to the mounting location.

Suspended light fixture support bracket prepared for installation at the electrical box (C) Daniel Friedman Suspended light fixture support bracket prepared for installation at the electrical box (C) Daniel Friedman

  1. Connect the light fixture to the supporting electrical box: lift the light fixture into place, connect the light fixture support bracket screws to the electrical box.

Light fixture support bracket connected to the electrical box (C) Daniel Friedman

Watch out: this is when you'll drop it! Sometimes I connect or wrap the multi-strand copper ground wire belonging to the light fixture to one of the ceiling box screws, preferably a ground screw or lug if one is present: just extra insurance against smashing the whole assembly on the sink or floor below.

  1. Connect the light fixture electrical wires to the appropriate circuit wires in the electrical box. Just below at left you can see the smaller multi-strand light fixture black wire ready to be joined with the lighting circuit black wires, and at below right a twist-on connector has completed the connection.

Circuit hot or black wires to be joined with the light fixture black wire (C) Daniel Friedman Light fixture black wires joined with a twist on connector (C) Daniel Friedman

Above left the circuit black or "hot" wires are ready for connection. Above right, wire nut in place.

Typical lighting switched circuit wiring connections:

The circuit "hot" lead (black) is carried to a switch and the wire returning from the switch is connected to the light fixture's "hot" or black wire.

If we're using a simple 2-wire black and white cable to and from the switch then we add a bit of black tape on the returning "hot" white wire to make clear that this is a switched hot wire not a neutral wire

. In that circuit the incoming hot black is connected to the black wire going to the light switch, and the returning light switch white wire is connected to the light fixture's own "hot" or black wire. We wrap black tape on the returning switch white wire to indicate to a future worker that this is not a neutral wire.

The circuit neutrals and light fixture neutral wires (usually white) are connected together.

The circuit grounding conductors, bonded together in the electrical box, are also connected to the light fixture ground wire. Additional connections may be specified between the light fixture's ground wire and metal fixture support clamps, fixture body, or other metal components that should be grounded for safety.

Light fixture ground wire ready to connect to electrical circuit grounding conductor (C) Daniel Friedman

Above the smaller multi-strand ground wire for the light fixture is ready to be joined to the circuit grounding conductor whose bonding and connections we showed earlier.

We used a twist on connector for this wire pair as well, making future light fixture disassembly and removal easier than if we'd crimp-clamped these wires together.

Below: the light fixture wiring connections are complete and we're ready to carefully push the wires back into the electrical box and install the cover. This is when you'll appreciate having enough space in the electrical box.

Light fixture wires properly connected to the circuit (C) Daniel Friedman

Watch out: it's easy to nick the electrical wire insulation on the sharp edges of the lighting fixture support bracket. If you nick a wire, don't be an ostrich with your head in the sand of fantasy that "it doesn't matter".

Pull the wire out and if it's long enough, cut away the damaged length and make a new connection. We've seen endless online debate about whether or not it's permissible or NEC code compliant to tape-repair a nicked electrical wire. I'm not going to tell you what you should do, but you can see what some people do do -just below.

Nicked electrical wire repair with tape (C) Daniel Friedman Nicked electrical wire repair with tape (C) Daniel Friedman

  1. Test the electrical circuit, wiring, & light fixture for safe, proper operation. That's fancy talk for turn it on and see if it works.

    You can see that the stainless steel finish cover for the electrical box (blue arrow) is down atop the light fixture globe while it is waiting for us to push wires into the electrical box. Test first, push wires second. The fewer times you have to bend and unbend copper electrical wires the better.

    Too much bending anneals and hardens the copper wire making future work more difficult and broken wires more likely.

Light fixture is tested before installing final covers. (C) Daniel Friedman

  1. Push the electrical wires into the electrical box. Take care to avoid sharp bends, kinks, nicks in the wire insulation or other amateur tricks such as loosening the twist on connectors and watching one of them fall into the sink trap.

Wires have been pushed into the electrical box (C) Daniel Friedman

  1. Install the light fixture electrical box cover. There may be more trouble to this final step than you think: if the cover mounting screws are too long you cannot tighten the cover against the ceiling. If they are too short ... well that's obvious.

Adjusting the light fixture cover mounting screw length

In the photo above the red letters indicate the various screws and fittings for a ceiling light fixture installation:

Cutting off a machine thread screw to length (C) Daniel Friedman Install ceiling light fixture box cover (C) Daniel Friedman

At above right you can see the cap nuts securely in place and the light fixture cover plate nicely against the ceiling surface.

Below is the ceiling light fixture after the installation was complete.

Ceiling light fixture suspended from a plastic electrical box (C) Daniel Friedman

Watch out: unless your ceiling-mounted electrical box is adequately supported, the procedures described here may not meet approval of your local electrical inspector when a fan or weighty ceiling light fixture is to be installed.

When mounting a heavy ceiling light and certainly if mounting a ceiling fan through an existing ceiling, the old-work electrical box can be secured directly to wood framing (below left, using a Madison Electric Products Smart Box as example), or if the exact light support location does not permit that direct connection one could use an old-work fan bar hanger that includes a deep 4-inch octagon box (below left - Racon fan box support).

Old work electrical box for mounting to framing - Madison Electric Products Smart Box Old work ceiling fan or light support bracket from Racon

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