At what point in a circuit should the protective device be located?

• A. As close to the power source as possible
• B. At the load side
• C. In the middle of the circuit
• D. Near the battery but not near the source

Answer: (A)

The protective device should be located as close to the power source as possible. Placing it at the source lets the device interrupt fault current right at its origin, protecting the source and the shortest run of wiring from damage, overheating, and fire risk. If protection were placed on the load side or somewhere in the middle, fault current could travel through more conductors and equipment before being opened, causing more damage and safety risk. Near the source ensures rapid disconnection of the entire downstream circuit and better overall protection.