How Do I Install A Light Fixture? – How Do I Fix That? Part 5

How Do I Install A Light Fixture? – How Do I Fix That? Part 5

While we might enjoy watching the various home improvement shows filling up cable programming, many of us can’t complete the most basic of home improvement projects. The How Do I Fix That? series will show you how to tackle a range of problems that have plagued homeowners for time immemorial. Each installment will provide a walkthrough for the problem at hand so you’ll know what to expect before you get started. Now, get into your old work jeans and roll up your sleeves – we’re going to get messy.

How to Install a Light Fixture

We’ve painted, installed blinds, cleared a clogged drain, and hung a heavy picture. This time, we’re going to install a light fixture in the bathroom.

How Do I Install A Light Fixture? – How Do I Fix That? Part 5

We’ll need to some prep work first, but this project will only require a Phillips and slotted screwdrivers, a pair of linesman’s pliers, a tape measure or ruler, and a pair of plastic wire connectors.

About the Wiring

We’re going to hang a four-lamp wall fixture from screws mounted inside a standard wiring box. The wiring uses standard household Alternating Current (AC). Remember: with AC current, there are no positive and negative wires. This is because AC current alternates polarity 120 times per second. In side the wiring box, you’ll see three wires coming out of a single plastic  sheath:  black, white, and a bare  copper wire.

The black wire is the “hot” ( or “load”) wire. It carries the 110 volts of AC current. AC power works when the electrical circuit has a return path. So, even when the polarity flips 120 times a second, the electrical current still needs to be complete to work.

The white wire is “neutral.” This wire is provides the return path for the electric current and completes the circuit. The neutral wire is also connected to ground in your home’s electrical breaker or fuse box.

The bare wire is part of the ground system. Many houses connect their electric breaker boxes to either metal plumbing connected to the municipal water supply or a ten-foot-long copper rod that’s been driven into the ground to act as ground. In the event of a short circuit, current from a hot wire will have a dedicated straight path to the ground. This is an important safety feature to prevent you from being electrocuted.

For example, let’s say the hot wire inside your old fridge has lost some insulation and that if you jostled it by moving this appliance, that bare wire touches the metal frame. Now, let’s you’ve been mopping the floor and you decide to move the fridge. BANG – contact! The electricity from the hot wire wants to find the quickest path to ground. But because neutral passes through all the circuits of your home, it doesn’t provide a direct path to ground. If the outlet in the wall is not grounded, then most of the electricity from that hot wire will pass through you to ground, possibly killing you (yes, this does happen).

However, if the outlet is grounded and the power cable includes a ground wire connected to your fridge’s metal frame, then the bulk of that electricity rushes down that grounding wire, saving your life. (TIP: NEVER cut off a plug’s grounding prong!)

Note: if you have a red wire coming from the wall mounted wiring box, that’s also a hot wire, and  probably part of a three-way switch circuit.

Turn the Power Off

How Do I Install A Light Fixture? – How Do I Fix That? Part 5

Shocking as that may seem, you’ll want to turn off the circuit breaker to the circuit you’ll be working on. If that’s inconvenient, make sure the light switch for that circuit is turned off. I like to put a piece of blue painters tape across it to prevent absent minded folks (mainly me) from accidentally flipping on the switch.

Understanding the Nuts and Bolts

Next, make sure the lamp mounting bracket is securely screwed into the correct position in the wiring box. If it’s too loose, the light fixture could shift, tilt, or otherwise get damaged. Insert the mounting bolts into the bracket. You’ll want to make sure they extend out far enough so you can twist on the decorative mounting nuts to hold the lamp in place.

Since this fixture’s faceplate extends out from the wall by 1” and the mounting nuts need a little over 1/8”, I’ve set the mounting bolts to extend out by 1 1/8”.

Let’s Get Wired

How Do I Install A Light Fixture? – How Do I Fix That? Part 5

Strip the insulation from the neutral and hot wires in the wiring box. You only need to strip off about 1/2”.

Your light fixture will should have black (hot), white (neutral), and bare (sometimes green)  ground wires coming out from it.  If light has stranded wires, take a few seconds to twist the end of each one so that they will insert smoothly into the plastic wire connectors.  You’ll want an assistant to hold the fixture while you connect the wires for the next steps.

How Do I Install A Light Fixture? – How Do I Fix That? Part 5

  1. Our mounting bracket has a screw for connecting the bare ground wire with the bare ground wire coming from light fixture’s frame. Form a little hook at the end of the bare ground wire from the box and loop it around the mounting bracket’s connecting screw. (Sometimes this screw is also green.)
  2. Form a hook in the end of the bare grounding wire from the lamp and loop it around the same screw. (See photo above.)
  3. Tighten the screw down firmly so the wires don’t slip out. This will also help you hold the fixture with only one hand. If the bracket you use doesn’t have this kind of connection, you can just insert the bare ground wires into a standard wire connector.
  4. Insert the ends of the light fixture’s white neutral wires and the neutral wire from the wiring box into a wire connector and twist until it’s snug.
  5. Give each wire a little tug to make certain they’re firmly in place. Repeat the same thing with the black hot wires.

How Do I Install A Light Fixture? – How Do I Fix That? Part 5

When complete, carefully tuck the wires into the wire box.

Let There Be Light!

How Do I Install A Light Fixture? – How Do I Fix That? Part 5

Put the light fixture in place so that mounting bolts extend through the faceplate. Tighten the mounting bolts into place.

Attach lamp shades. Insert bulbs. Turn on the electricity. Now, flip that switch! Your vanity is now complete. By the way, you look mahvelous!

All photos (except header image) courtesy of Vernon Trollinger.

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Vernon Trollinger is a writer with a background in home improvement, electronics, fiction writing, and archaeology. He now writes about green energy technology, home energy efficiency, the natural gas industry, and the electrical grid.