To use a clamp meter in commercial applications:
Clamp meters are used to measure circuit loads on feeders and branch circuits at switchboards.
Measurements on branch circuits should always be made on the load side of the circuit breaker or fuse.
1. The balance condition and load condition of the feeder cable should be checked: the current on all three phases should be approximately the same to minimize the current returning to neutral.
2. Also check whether the neutral line is overloaded. With harmonic loads, even if the feeder phases are balanced, the neutral conductor may carry more current than the feeder.
3. Each branch circuit should also be checked for possible overloading.
4. Finally, the ground loop should be checked. There should be very little current to ground.
