So we have a need to hook up a meter to a circuit which connects an emergency generator to an automatic transfer switch.
As you'd imagine, the circuit is normally not energized .. and so, the meter is normally dead and doesn't report anything.
is there some way to keep the meter powered while the circuit i'm monitoring is dead? I think not.. (other than to wire up a battery and a couple diodes rated for >277v and probably break lots of NEC rules)
metering a circuit normally off
Re: metering a circuit normally off
Do you have high voltage AC power nearby that you can use to power the meter? Do you have this available on the building side of the disconnect switch?
If you do, I would connect the meter voltage reference wires there. The meter will be powered and will get its voltage reference. You can then have your CTs on the wire that lead from the generator to the building. The meter will not normally measure any current (until the generator is producing power). When the generator is running the meter will have both the voltage references it needs and the current reads from the CTs. Would this solve the issue?
Best regards,
If you do, I would connect the meter voltage reference wires there. The meter will be powered and will get its voltage reference. You can then have your CTs on the wire that lead from the generator to the building. The meter will not normally measure any current (until the generator is producing power). When the generator is running the meter will have both the voltage references it needs and the current reads from the CTs. Would this solve the issue?
Best regards,