15 Things You Should Know Before Doing DIY Electrical Work

Updated: May 23, 2024

Don't do any DIY electrical work if you're not fully educated on the subject. Here is some essential knowledge and must-have tools for DIY electrical projects.

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Use GFCI Outlets Whenever Possible

GFCI stands for Ground Fault Circuit Interrupter and it helps to monitor the amount of power being used in one outlet. For example, if you’re using one outlet for a powerful appliance or device, this will help to prevent electrocution—especially for those that are near water sources. GFCI will cut the power any time a slight variation is detected. Here’s how to install GFCI outlets.

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Cutting Wires Too Short Can Lead to Problems Down the Road

If your wires are cut too short, you’ll experience poor connection from the electrical circuit. For example, having a little wire slack in an electrical box is good, but not too much. You want to make sure wire connections are tight, while also giving the wire some breathing room.

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Basic Wire Strippers

There are endless types of elaborate wire strippers available, but most DIYers (and many pros) prefer the simple versatility of this type. Aside from stripping wire, they also cut wire or cable, allow you to hook wires for screw terminals and act as pliers.

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Safety Switches vs. Circuit Breakers

Knowing the difference is huge when understanding electrical panels. Safety switches are to help prevent any electrical issues that can happen to you personally. It can detect electrical shocks before anything were to occur and will switch off the electricity before something happens. This can happen if a faulty electrical appliance is being used, as well as issues with the electrical wiring.

Circuit breakers simply turn off the power when there’s too much electrical current being used. Having too much current can overheat an electrical appliance or wiring, which of course can lead to electrical fires or other damages. If you’re interested in connecting a new circuit, here’s how to do it.

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Circuit Tester

A simple circuit tester with two probes can help answer a variety of electrical questions: Which wire is hot? Is this outlet wired correctly? Is there a reliable ground? Most circuit testers are designed for just one range of voltage. This one tests them all.

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There’s a Difference Between Kinds of Circuit Breakers

To help you understand which electrical protection goes where, consider what each type of breaker was designed to do and make sure to follow the national electric code.

Standard circuit breaker

Circuit breakers protect home electrical wiring and equipment like furnaces, air conditioners, dryers and stoves. Standard circuit breakers are better at protecting wiring and equipment than preventing fires and protecting people. That’s why they have largely been replaced by GFCIs and AFCIs. There are only a few places left where standard circuit breakers can be used, typically for large home electrical appliances.

Ground fault circuit interrupter

Ground fault circuit interrupters (GFCIs) protect people in areas where they are likely to be using small appliances and where water is present. GFCI breakers and outlets have been around for a while, and most people know they’re required in bathrooms, kitchens and outdoors, but our experts are still finding home electrical violations, especially in these areas: garages, crawl spaces, storage/work areas in unfinished basements, wet bars (within 6 ft. of a sink), and sump pumps. And don’t forget that GFCIs need to be readily accessible in order to be reset. This means they shouldn’t be installed on the ceiling or buried under a hydro massage tub without an access panel.

Arc fault circuit interrupter

Arc fault circuit interrupters (AFCIs) prevent fires in all living areas where appliance cords are prone to be pinched or crimped, or chewed by pets.They used to be required only on bedroom circuits, but the National Electrical Code now requires AFCI protection in all living areas. They’re equipped with sophisticated electronics that can detect an arcing condition (like in a frayed lamp cord), which may not be detected by a standard circuit breaker until after a fire has started. AFCI protection is not just required for new construction; it’s now also required where branch-circuit wiring is modified, replaced or extended into existing homes.

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wire sizes gauge

Using Different Wire Gauges

Using the same wire gauge will help to prevent overloading. You can do this by evaluating the size of your wiring, and applying the right type of gauge to your breaker.

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Push-In Wire Connectors

Twist-on wire connectors (often referred to by the brand name “Wire-Nut”) are the standard method for joining wires. But for ease and speed, push-in connectors are much better. They’re also a great problem-solver when the wires in a junction box are too short to accommodate a twist-on connector. Some push-in connectors have just two wire ports. Others have six or more. Here’s a good assortment kit.

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overfilled electrical boxes

Make Sure Your Electrical Box is Big Enough

Too many wires stuffed into an electrical box can cause dangerous overheating, short-circuiting and fire. The National Electrical Code specifies minimum box sizes to reduce this risk.

To figure the minimum box size required, add up the items in the box:

1 – for each hot wire and neutral wire entering the box

1 – for all the ground wires combined

1 – for all the cable clamps combined

2 – for each device (switch or outlet?but not light fixtures)

Multiply the total by 2.00 for 14-gauge wire and by 2.25 for 12-gauge wire to get the minimum box size required in cubic inches. Then choose a box with at least this much volume. Plastic boxes have the volume stamped inside, usually on the back. Steel box capacities are listed in the electrical code. Steel boxes won’t be labeled, so you’ll have to measure the height, width and depth of the interior. Then multiply to find the volume.

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Don’t Install the Wrong Cover On an Outdoor Receptacle

On outdoor receptacles, flat covers provide protection only when a receptacle isn’t in use, but it’s not uncommon for extension cords to be plugged in for extended periods of time; for holiday lights, for example. In-use or “bubble covers” provide protection at all times. The national electrical code defines a “wet location” as an area that is subject to saturation with water or other liquids, and unprotected locations exposed to the weather.

The national electric code has another definition for “damp locations” that is more subjective, but if you think the receptacle is going to get wet, use an in-use cover. And don’t forget the weather-resistant receptacle. The national electric code requires that all 15- and 20-amp receptacles be rated as weather-resistant and tamper-resistant when installed in both wet and damp locations.

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Don’t Forget Tamper-Resistant Receptacles

Tamper-resistant receptacles are designed to stop a kid from inserting an object, such as a paper clip. They’re required for all locations, indoors and out. Tamper-resistant receptacles are a great invention, so use them — it’s national electric code. We’ll show you how to correctly install a tamper-resistant outlet.

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Double Check with a Non-Contact Voltage Tester

When doing any work with the electricity in your home, it’s always important to turn off the electrical circuit. However, some would make the mistake of not testing the wires of an electrical box before doing any work. Make sure to test it to make sure everything is “dead” before moving forward. Plus, these testers are pretty cheap.

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Identify the Neutral Terminal

Connecting the black hot wire to the neutral terminal of an outlet creates the potential for a lethal shock. The trouble is that you may not realize the mistake until someone gets shocked, because lights and most other plug-in devices will still work; they just won’t work safely.

Always connect the white wire to the neutral terminal of outlets and light fixtures. The neutral terminal is always marked. It’s usually identified by a silver or light-colored screw. Connect the hot wire to the other terminal. If there’s a green or bare copper wire, that’s the ground. Connect the ground to the green grounding screw or to a ground wire or grounded box.

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Make Sure to Secure All Cables

Cable that’s not secured can strain the connections. In metal boxes, the sharp edges can cut the insulation on the wires. Single plastic boxes do not require internal cable clamps, but the cable must be stapled within 8 in. of the box. Larger plastic boxes are required to have built-in cable clamps and the cable must be stapled within 12 in. of the box. Cables must be connected to metal boxes with an approved cable clamp.

Make sure the sheathing on the cable is trapped under the clamp, and that about 1/4 in. of sheathing is visible inside the box. Some metal boxes have built-in cable clamps. If the box you’re using doesn’t include clamps, buy clamps separately and install them when you add the cable to the box.

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Keep Low-Voltage Wires Away From Electrical Cables

It’s really tempting to fish low-voltage wires (like coax and Cat-5e) through existing holes occupied by electrical cables, but don’t do it! Even though cables are insulated, the high-voltage current can interfere with the signal in the low-voltage wires. This could result in bad TV reception or unreliable phone and Internet service. Drill a new hole, and keep the new low-voltage wire several inches away from electrical cables. It’s OK to run low-voltage wires perpendicular to cables, and it’s also OK to run low-voltage wires next to electrical wires that are encased in conduit or metal sheathing.