10 top DIY no-nos found by electrical inspectors

Jim Mallery | Improvement Center Columnist | March 22, 2012

The do-it-yourself electrician is in a little different ballpark than other DIYers. If you do your own plumbing, what's the worst that can happen? You spring a leak and maybe grandma's ashes get soaked. DIY carpentry may mean a crooked door or squeaky floor. But mess up the electrical, and lives are at stake.

That's why most municipalities don't encourage DIY electricians. If there's any doubt, they shout, hire a licensed professional. You can find local electrical pros online.

Still, homeowners can take on their own wiring, though electrical inspectors may cringe when they visit. This list sheds light on 10 common code problems that inspectors find:

1. Wrong size, A. Nowadays, lighting usually is on a 15-ampere circuit, and receptacles are on 20-amp circuits. You can't run a 15-amp line to a receptacle. There are exceptions, of course. For instance, a refrigerator may plug into a dedicated, 15-amp circuit.

2. Wrong size, B. A 15-amp circuit can use 14-gauge wire, which is also called AWG, but a 20-amp circuit needs a minimum of 12-gauge: the smaller the number, the thicker the wire. You cannot put 14-gauge wire on a 20-amp circuit. Other, specialty circuits have their own requirements. For example, a 240-volt circuit to the clothes dryer would use a 30-amp breaker and require 10-gauge wire.

3. Wrong type. Standard household wire, often called by the brand name Romex, is just that: household. If wire is used in other ways -- underground, for instance, it has to be rated for that use.

4. Too much. A common code violation is the overloaded box. Because wires emit heat and crowded boxes are dangerous, there are limits as to how many wires may be in a box, depending on the size of the box. It's kind of like trying to cram too many relatives into a room at Thanksgiving -- after a while, things can get dangerously warm, and there's bound to be a flare up. Also, all wire connections must be made inside an approved box. You cannot just wire-nut two wires together and leave them dangling in the attic.

5. No secrets. All your junction boxes must be visible and accessible. No boxes hidden in wall, and no boxes covered by insulation in the attic. That latter gets especially tricky if you are tapping into a circuit in the attic where the wires are covered by insulation. You must find a way to get your splicing in a junction box located above the insulation.

6. Not enough tail. DIYers are prone to leaving their tails too short. That is, the wirer cuts the wire too short at the receptacle box, making it difficult to attach the fixture and fold the wires back into the box. Inspectors look for a 5-inch to 6-inch tail, which makes it easy to attach the fixture and accordion the wire into the box.

7. Too snug. An over-muscled homeowner, or a homeowner who is trying to pretend that he is over-muscled, may hammer the wire staples too tight when securing a wire, thus pinching the insulation and creating a fire hazard.

outlet with wires

8. Outlet spacing. As a wired society, we need lots of outlets. To discourage the use of dangerous extension cords, code requires outlets within 6 feet of a corner or opening and every 12 feet along a wall. On kitchen backsplashes, you must have an outlet every 4 feet, or 2 feet from a corner. And kitchens require two receptacle circuits, 20 amps each.

9. Interrupters. A ground-fault circuit interrupter, or GFCI, is required for any circuit where water might be present, such as kitchens, laundry rooms, bathrooms, garages or outdoors; these interrupters keep you from being electrocuted. Arc-fault interrupters, or AFCIs, are designed to prevent fires caused by electrical arcing. As of 2008, AFCIs are required in nearly all 15-amp and 20-amp circuits except those covered by GFCIs.

10. Grounding. All wiring must be continuously grounded back to the electrical panel. Metal boxes and all fixtures must be attached to that grounding. Since electricity wants to flow to ground, it is much better that it race through your ground wire to a properly grounded panel than, say, through your body.

These are a few of the items that electrical inspectors will look for. There are tons of others in the voluminous national electrical code. You can't know it all, but you'd best know what applies to your project.