measuring current on an existing site lighting circuit.

[ElectricPersonality]

General question for experienced testing folks. We need to add some new sight lights as part of a parking lot expansion. Would like to determine if the nearest site light circuit to the expansion has spare capacity for the additional lights. What is the best method to measure the current at night for the existing site light circuit? Seems would have to find the nearest light, then do some type of test to determine what other lights are wired to the same circuit, and then find the last light in the circuit, (closes to the source panel electrically), and then measure the current draw for the entire circuit at this last light? As typical, there are no as build drawings that indicate how these lights were circuited 20 plus years ago.

 

[LarryFine]

What is the best method to measure the current at night for the existing site light circuit?

Measure each circuit's current with a clamp-on ammeter right in the panel.

 

[ElectricPersonality]

how do you measure

Measure each circuit's current with a clamp-on ammeter right in the panel.

how do you determine which circuit on the panel is feeding the nearest site light you want to connect the new lights after you know the current draw on each circuit at the panel?

 

[don_resqcapt19]

how do you measure

how do you determine which circuit on the panel is feeding the nearest site light you want to connect the new lights after you know the current draw on each circuit at the panel?

Turn the circuits off one at a time to determine which circuit feeds which lights.