Which type of receptacles in aircraft hangars require GFCI protection?

In aircraft hangars, GFCI (Ground Fault Circuit Interrupter) protection is particularly important due to the presence of moisture and potentially hazardous electrical conditions. While it's true that certain receptacles are specified to have GFCI protection, the appropriate answer encompasses all receptacles that could pose a risk.

125-volt, single-phase, 15 and 20-ampere receptacles typically require GFCI protection, as do the 250-volt, three-phase, 15- and 20-ampere types. Although the question might seem to focus solely on one category, recognizing that 250-volt single-phase receptacles can also present a risk is crucial.

The need for GFCI protection extends across various receptacle types in an aircraft hangar setting, as ensuring safety in environments with high moisture and flammable materials is paramount. This is why the answer indicating all receptacle types requires GFCI protection is correct: it acknowledges the necessity of safeguarding all possible electrical configurations in such specialized locations.