Buyer Beware: Potential electrical problems when buying an older home

By Mark C. Ode | May 15, 2022
Illustration of a worker holding a magnifying glass to a tiny house. Image by Richard P. Bingham.
I conducted a courtesy electrical inspection for a friend who had purchased a home from a real estate agent, who previously owned and occupied it. 

I conducted a courtesy electrical inspection for a friend who had purchased a home from a real estate agent, who previously owned and occupied it. The house had supposedly been totally rewired by an “electrician” in the year prior, and there was a fairly detailed home inspection report that showed all the electrical work was done in accordance with the latest National Electrical Code .

The home inspector had supposedly certified the electrical system and many other building code aspects. Real estate companies and potential buyers often use inspectors to review a home before concluding a sale. Many states require home inspectors to be licensed and to undergo initial and then periodic training. Home inspectors must alert buyers of various safety and code issues with a written report. Commercial buyers and sellers do the same, but they call the service “due diligence” and often hire engineers to review and report on a property’s condition.

The seller, buyer or both parties, in some cases, can employ a home inspector, engineer, qualified electrical contractor or other qualified person. Any construction or code issue can be used as a negotiation tool with either party to decide what repairs are involved and who will pay to fix the problems.

There can be legal ramifications if the seller falsely claims certain items have been replaced and work done when they weren’t properly installed or work wasn’t completed. Always check the contract and the law.

Discrepancies from the report

My friend’s home allegedly had new wiring throughout. However, I discovered that the existing wiring had not been replaced, as noted in the real estate report, and the original NM cable did not contain an equipment grounding conductor (EGC). This is indicative of wiring that was done in the mid-1950s or earlier, when receptacles were a nongrounding type.

When I removed and viewed the grounding-type receptacles’ internal wiring, I discovered the lack of equipment grounding in the cable. Evidently, to trick the home inspector into believing that there was an EGC connected to the receptacle’s equipment grounding screw, the installer had connected a jumper from the equipment grounding screw to the neutral conductor on the receptacle. If the home inspector had used a receptacle tester, it would indicate normal conditions. The home inspector would not know what the seller had done without removing the receptacle like I did and inspecting the receptacle and the receptacle box interior.

Also, none of the “newly installed” receptacles were tamper-resistant as required in 406.11 of the NEC . Section 406.4(D) would have permitted nongrounding receptacles to be replaced with another one of the same or a ground-fault circuit-interrupter (GFCI) type where the receptacles or cover plates are marked with “No Equipment Ground.” These nongrounding-type receptacles could also be replaced with a grounding-type receptacle, where supplied though a GFCI, and the receptacle or the cover must be marked “GFCI Protected” and “No Equipment Ground.” The markings must be visible after installation. None of these “fixes” are acceptable, since the home was supposed to have been totally rewired (with NM cable with an EGC) to present NEC requirements.

In the kitchen

There was also a kitchen island with a slide-in range and multiple duplex receptacles. The range had a nameplate rating of 12.8 kilowatts (kW). Using 220.55, Table 220.55 and notes 1 and 4, a value of 8 kW based on Table 220.55 times 5% equals 8.4 kW (400W plus 8 kW), divided by 240V equals 35A. The existing branch circuit for the range was sized at No. 10 AWG copper for the ungrounded conductors with a 40A two-pole breaker, and it should have been sized at a No. 8 AWG copper.

The range cable and the cable for the 20A receptacle circuits were also installed in PVC under the concrete floor from the island to the opposite wall. This is a violation of 300.5, since NM cable under a concrete slab is a wet location, and it cannot be installed in this type of location. This underfloor wiring must be replaced with UF cable or a wiring system acceptable in a wet location.

Take the saying “Let the buyer beware” seriously, especially with electrical wiring in a home. These were major electrical safety issues, and misrepresentation of these installations may result in legal ramifications. When in doubt, always check with an electrical expert.

Header image by Shutterstock / Eamesbot.

About The Author

ODE is a retired lead engineering instructor at Underwriters Laboratories and is owner of Southwest Electrical Training and Consulting. Contact him at 919.949.2576 and [email protected]





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