Which statement correctly reflects the maximum allowed voltage for branch circuits in typical dwelling units?

Which statement correctly reflects the maximum allowed voltage for branch circuits in typical dwelling units?

• A. 120 volts
• B. 240 volts
• C. 208 volts
• D. 277 volts

Answer: (A)

Residential electrical systems are built around a 120/240-volt split-phase supply. Branch circuits that feed lighting and most receptacles in a dwelling are designed for 120 volts nominal. This means you expect about 120 V from hot to neutral, which protects wiring and devices designed for this standard. The 240 V circuits you might encounter are dedicated circuits for large appliances that run on both hot legs, not general lighting or outlets. Higher voltages like 208 V or 277 V are typical of commercial or multi‑tenant three‑phase systems, not standard dwelling units.

Residential electrical systems are built around a 120/240-volt split-phase supply. Branch circuits that feed lighting and most receptacles in a dwelling are designed for 120 volts nominal. This means you expect about 120 V from hot to neutral, which protects wiring and devices designed for this standard. The 240 V circuits you might encounter are dedicated circuits for large appliances that run on both hot legs, not general lighting or outlets. Higher voltages like 208 V or 277 V are typical of commercial or multi‑tenant three‑phase systems, not standard dwelling units.