Make No Mistake: Electricity Is Not for Amateurs

Power Quality 0419 Photo Credit: Richard P. Bingham
Photo Credit: Richard P. Bingham

Following up on a home inspection for the prospective buyer of a single-family home, the inspector’s report listed two electrical items: two receptacles had reversed neutral and line connections and two others were ungrounded. The one-and-a-half-story structure, originally built in 1953, had mostly BX cables with two circuits updated to NM cables on a mix of 15- and 20-ampere (A) breakers along with a dual 20A, 30A and 50A for a wall air conditioning unit, electric dryer and electric stove, respectively. Renovations were done over time, including finishing three-quarters of the basement. All of the receptacles were changed to three-prong duplex ones and the toggle switches were changed to the “decora” style.

A more thorough testing of all of the receptacles found six to be ungrounded and four with neutral and live wire reversals. One neutral-live reversed receptacle was in the second-floor bedroom above the first-floor bedroom receptacle and a basement receptacle with the same problem. On another wall in the basement, a receptacle directly below a three-gang switch box had the fourth neutral-live reversal (see photo). The left switch was part of a three-way circuit for half of the 12 recessed lights in the basement, the middle controlled one recessed light, and the right controlled the remaining lights.

Tracing the involved circuits back to the panel revealed four different circuits in the three-gang box. The left switch was on one 20A breaker, the right on another 20A, and the middle on a third 20A breaker that controlled the single light using the middle switch, as well as the four neutral-live reversed receptacles. Further investigation found the same circuit fed two receptacles in the first-floor kitchen peninsula and wine refrigerator. These two receptacles did not exhibit the neutral-live reversal. One more basement receptacle (for the washing machine) was found on the circuit.

The number of National Electrical Code violations and bad practices on a single circuit was astonishing. Apparently, this was an uneducated homeowner’s DIY project gone wrong. Amazingly, the house hadn’t burned down. Neither the kitchen nor laundry receptacles were GFCI-protected. The laundry circuit should have been a dedicated 20A, not a shared one with six other receptacles and a dozen lights. Based on the path of the wires, the next likely receptacle in the circuit was in the basement below the two bedroom ones. Despite the measured voltages indicating reversed neutral-live, it was wired correctly, so the reversal likely took place between the laundry receptacle and that basement one.

 One possible explanation was a buried box concealed in the wall somewhere near the laundry’s previous location, as evidenced by an abandoned laundry sink in a closet. A junction box above the suspended ceiling fed the problem receptacles, and its feed had the neutral-live reversed. Another circuit in that box ran to the solo recessed light for the middle switch in the three-gang box. That made eight 12 AWG conductors with four grounds with two cable clamps for BX, two for NM, in box rated for six wires. To compound the problem, the BX wires had missing insulation.

The wires from the junction box went to the solo recessed light and fed a switched leg circuit down to the center switch in the three-gang box with NM cable. The white and black wires went to line conductors in the box, one fed down to the receptacle below the switch box and the other to the switch to control the light. No black tape or other marking was used to indicated a switched leg on the wire. To get a neutral to the receptacle below, a wire was connected to the neutral from another circuit; in fact, all three circuits had the neutral conductors in the box connected together. That cable down to the receptacle was an unsecured BX cable, ungrounded to the plastic box, and no cable clamp on the metal box where the receptacle was. Hence, no ground there along with the neutral-live reversal. While the switch did have a neutral conductor present in the box, it wasn’t from the circuit that the line conductor was. A fourth circuit in the box had its neutral conductor twisted up in the mess, but the line conductor was capped with a wire nut capable of five No. 12 wires. Multiple conductors went through some strain relief in the box, offset to the sides, so they weren’t properly secured. Only one of the switches had the ground on the switch connected to a grounding conductor. The twisted grounding conductors had no wire nut.

Overall, in the 640-square-foot finished portion of the basement, there were a total of only three receptacles on the 120 linear feet of wall, clearly not enough to have one within a 6-foot reach of a device. To feed a fish tank and another piece of equipment, holes were cut in the drywall, and extension cords were run from the laundry receptacle in the adjacent room.

Over two dozen Code violations and bad practices on a single circuit will require significant rework and warrants a more thorough investigation of the other circuits. This was another poster child that proved electricity is not for amateurs.

About the Author

Richard P. Bingham

Power Quality Columnist

Richard P. Bingham, a contributing editor for power quality, can be reached at 732.248.4393.

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