Don't make these mistakes, DIYers.
The Most Common National Electric Code Violations DIYers Run Into
Published on Oct. 30, 2024
The National Electrical Code (NEC) exists to keep people and property safe from electrical hazards and fires. Electricians like me and Chris Lozano of Frontdoor Home Services spend years learning the ins and outs of electrical installations. Homeowners who DIY their own electrical work have to follow the same rules, as well as any local electrical and building codes.
Below, Lozano and I walk you through some common issues that you may run into when working on your own home. It’s not an exhaustive list! The NEC updates every three years, so verify with your local electrical inspector which code cycle your jurisdiction follows. Requirements apply to new construction and repairs, so you don’t have to rush out and fix everything. As always, call a licensed electrician if you need help.
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Mislabeled Breakers
The NEC requires that circuit breakers be legibly marked so you know exactly what they do. Well, I don’t know about you, but I’ve never lived in a house where the breakers were labeled right. That’s a problem if you’re doing DIY electrical work or if you need to shut off a circuit quickly when there’s a problem.
Lozano says the easiest way to fix a poorly labeled breaker box is to ask a friend or family member to switch each breaker off one by one. When the lights or power go off in the room, you know what the breaker controls. (If you’re by yourself, you can use a radio, circuit tracer or receptacle tester.)
Label each breaker, or make a panel schedule and post it inside or adjacent to the door.
No Ground Fault Protection
If you’ve sold or bought a house or upgraded your kitchen, bathroom or garage, you’ve probably had an inspector flag a missing ground fault circuit interrupter (GFCI), especially if your home is older. GFCIs protect you from electric shock, and they’re required in multiple places around your home where water is present.
Because GFCI requirements have expanded over time, many homes lack them, where the NEC currently requires them. To get your circuits up to code, there’s no need to install a GFCI in every outlet. Install one GFCI in the first outlet after the panel, and daisy chain the rest (these can be regular grounding-type receptacles). Or, put in a GFCI breaker.
- Pro tip: If your bathroom receptacles go out, and you can’t figure out why, look for a GFCI in another bathroom. The NEC allows bathrooms to be wired together, and because one GFCI receptacle can protect an entire circuit, you probably have one upstairs that’s tripped.
No Dedicated Circuit
Your kitchen sure would feel roomier if you ditched that countertop microwave and installed one over the stove, right? If you DIY the installation, resist the urge to tap off an existing circuit. Make sure you run a dedicated circuit, also called an individual branch circuit.
A built-in microwave/range hood combo, or any appliance “fixed in place” that shares a circuit with lights or countertop receptacles, must use less than 50% of the branch circuit rating, which in your kitchen is 20 amps. Even if you purchased a smaller over-the-range microwave, you’re cutting it close by staying under 10 amps.
Plus, if you plan to plug in your new microwave instead of hard-wiring it, the NEC requires a dedicated circuit, no matter the amp draw. Finally, over-the-range microwave manufacturers nearly always require dedicated circuits, and the NEC says you have to follow the listing and labeling instructions provided by the manufacturer.
Overloading Circuits
Let’s say you don’t want the hassle of DIYing a range hood. You’d rather free up space by putting your new microwave in a cabinet under the counter. Can you feed a new cabinet receptacle from the countertop receptacle directly above? Nope.
Kitchens (including adjoining areas like pantries and dining rooms) have two 20-amp small appliance branch circuits that supply your countertops, wall and floor receptacles and fridge (although many people put fridges on their own circuit). Everyone’s kitchen is different, so the NEC wants these small appliance circuits reserved for toasters, air fryers, coffee makers and other small portable countertop appliances.
Adding a new receptacle in a cabinet adds a permanently plugged-in load that could potentially overload your circuit.
Open Junction Boxes or No Box at All
Lozano sees these a lot. Junction boxes must be covered, and you can’t have splices made outside of a junction box. I once found several splices just dangling in a wall cavity, which I remedied by adding a box before the device I was installing.
The next house I moved to had open boxes in the attic. The splices were fine, so I added “blanks,” which are covers that don’t have any openings. If you’re doing a DIY project and come across any open junction boxes, you can do the same to bring them up to NEC safety requirements.
Permanent Extension Cords
When you work on a project in your garage, are you constantly stepping over multiple extension cords? Have they been there longer than you can remember? The NEC doesn’t allow extension cords to be used as a substitute for permanent wiring, so for your next DIY project, why not put in some new surface-mounted receptacles?
If you do add receptacles in your garage, consider the loads you’ll be using. New garages must have one 20-amp circuit, with one receptacle in each vehicle bay not more than 5 1/2 feet off the floor. Additional circuits can be 15 amps or greater.
Wrong Outdoor Receptacle Covers
Newly constructed homes must have two outdoor receptacles for plugging in lawn tools, holiday lights, and other electrical needs. (You may just have one, or even zero if your home is old enough.) These outdoor receptacles could be in “wet locations,” where they’re subject to weather or water intrusion, or “damp locations,” such as under porches and eaves.
The NEC requires that receptacles in damp locations be weatherproof when nothing is plugged in and that the receptacle covers be closed. In wet locations, the receptacle must be weatherproof even when the plug is inserted. Wet location covers are called “bubble covers” or “in-use” covers, and you can use them in damp locations, too.
When I moved into my home, I noticed the deck above did nothing to stop rain from dripping on the lower porch receptacle. So, I added in-use, weatherproof covers, and it’s an easy DIY project for you, too. “Weatherproof receptacle covers will go a long way in prolonging the life of the receptacle installation,” Lozano says.
Inaccessible GFCIs
“Installing GFCIs in a location that is hard to find or access can create headaches for homeowners and electricians alike,” Lozano says. A great example of this is behind a refrigerator. The NEC requires kitchen and garage receptacles to be GFCI-protected, but it’s very hard to move a fridge if the GFCI trips.
That’s why the NEC requires GFCIs to be installed in a readily accessible location. No climbing up ladders, no fumbling for a key, no moving something heavy. A great way to get around difficult placement, like a garage door opener on your ceiling, is to install a breaker or use one GFCI to feed other receptacles. “A tripped GFCI can affect a whole circuit, creating a real issue,” Lozano says.
No Neutral at Switch
Most switches don’t require a neutral to operate, so for decades, the NEC didn’t require electricians or homeowners to bring a neutral to switch boxes. But, today’s smart switches and dimmers have electronics, and most of them do need the neutral. The NEC now requires neutrals at switch boxes, or there must be a way to easily pull one later (like through a pipe).
But most homes aren’t piped with conduit. So if you’re DIYing an addition, it’s best to just bring one now, even if you don’t use it. If you’re adding smart switches to your older home, look for ones that don’t require a neutral (they do exist).
Improperly Replacing Non-Grounding Receptacles
I used to live in a very old house with knob-and-tube wiring. Knob-and-tube has two wires: hot and neutral. (No “ground wire,” more accurately called an equipment grounding conductor (EGC).) A previous homeowner got sick of having nowhere to plug in a three-prong plug and swapped out the two-slot, non-grounding type receptacles for three-slot, grounding-type ones.
That was a code violation. I had three ways to fix it:
- Pull an ECG from the service panel to every outlet in the house. This is the best but most expensive option.
- Put the non-grounding receptacles back. This is the cheapest, but I’d still have the three-prong problem.
- Put in a GFCI, which would provide shock protection, accept a three-prong plug and be code-compliant. This is what I chose.
If you put in GFCIs like I did, the NEC requires that you label the front of the receptacle: “No Equipment Ground.” (Stickers come with the GFCI.) If you use one GFCI to control other grounding-type receptacles on the same circuit, label these “No Equipment Ground” and “GFCI Protected.”
Not Installing Tamper-Resistant Receptacles
Tamper-resistant receptacles are required everywhere in your house to keep kids from sticking things in the slots. You don’t have to run out and replace them if you don’t have them, but if you’re adding a new room or swapping out an old receptacle, make sure you buy tamper-resistant ones. (One exception is if you happen to be replacing a two-slot, non-grounding receptacle with another of the same type.)
Overfilling Electrical Boxes
The NEC has specific box fill requirements for junction boxes to minimize heat buildup. If you open a box during a DIY project and discover a packed box, put in a bigger one. “Wire nuts and connections can come loose when trying to fit everything inside of the box,” Lozano says, and if you’re using a metal box, “[wire] insulation can become damaged and leave wiring exposed.” That’s a fire waiting to happen.
Leaving Christmas Lights Up Too Long
Are you a Clark Griswold when it comes to Christmas lights? DIY holiday displays are becoming more and more common, with lights, sound and inflatables popping up way before Thanksgiving. Some people even extend that holiday spirit into a year-round affair, with Valentine’s, Halloween and Fourth of July decorations in every imaginable color and design.
Be aware that the NEC has a 90-day limit on “temporary installations” of holiday lights. Typical big-box lights aren’t made to withstand the elements forever. If you plan to light up your yard 365 days a year, invest in permanent lights that are listed for this purpose.
About the Expert
Chris Lozano is a master electrician and virtual electrical expert at Frontdoor, a home services app that connects you to on-staff, qualified experts to help you solve your home maintenance issues. It’s like telehealth for your home.
