On a contactor, A1 and A2 are the supply terminals. Which statement correctly describes their roles?

• A. A1 is the load and A2 is the supply
• B. A1 is the ground and A2 is the hot
• C. A1 is the source/positive and A2 is the return/neutral/common
• D. A1 and A2 are both neutral

Answer: (B)

A1 and A2 are the coil input terminals of a contactor. They receive the control voltage that energizes the coil, and when the coil is energized, it creates a magnetic field that pulls the contacts together to switch the load circuit. This coil circuit is separate from the load circuit, so A1 and A2 aren’t ground and hot in the sense of powering the load. For AC coils, polarity doesn’t matter and either lead can be used; for DC coils, polarity does matter, with A1 typically being the positive and A2 the negative. In short, these terminals are simply the coil supply points used to energize the contactor.