Which steps would you take to verify a miswired 120/240 V circuit between two receptacles and a panel?

• A. Verify the hot-to-hot and hot-to-neutral voltages at both receptacles.
• B. Inspect only the panel for correct breakers.
• C. Check hot-to-hot and hot-to-neutral voltages, verify correct breakers, inspect wiring at panel and receptacles, and correct miswiring.
• D. Ignore safety and proceed.

Answer: (C)

In a 120/240 V residential circuit, the two hot conductors must come from opposite phases so you get 240 V between them and 120 V from each hot to neutral. To verify a miswiring, you need to check both relationships and the wiring setup, not just one part of the circuit.

First, measure between the two hot conductors at the receptacles. You should see about 240 V, which confirms the two legs are on opposite phases. Then measure from each hot to neutral at the receptacles; you should see about 120 V on each. If either reading is off, you’ve found a misconnection that affects the circuit’s operation and safety.

Next, inspect the panel to confirm the breakers feeding the circuit are a proper two-pole breaker with a common trip or a tied pair. This ensures the two hot legs are simultaneously disconnected and on opposite phases. If the breakers aren’t correct or aren’t tied, you can’t rely on the circuit to deliver the expected 240 V or to trip safely in a fault.

Finally, inspect the wiring in the panel and at the receptacles. Verify that the two hot conductors are landed on the correct terminals, the neutral is properly connected and continuous, and there are no loose or damaged wires. Correct any miswired connections so the hots remain on opposite phases, the neutral is properly shared, and the grounding is sound.

This method ensures you confirm the voltage relationships, verify the proper protective devices, and validate the physical wiring, which together are essential to safely and correctly operating a 120/240 V circuit.