At the meter socket of a 200 amp service entrance I've recorded what I believe is the starting current (or LRA) of a 10 HP compressor motor that is approximately 310 amps. How do locked rotor amps affect the sizing of the service entrance conductors and equipment? Are locked rotor amps considered non continuous loads that are noted in NEC 230.42(A)(1)? Is this service overloaded and in need of an upgrade?
Motor LRA and Service Entrance
- Thread starter TW_EE
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- Logan, Utah
Welcome to the forum.
LRA is not what you use when sizing service entrance conductors, feeders or branch circuit conductors.
When coming up with conductor sizing for a motor you will use the Tabulated ampacity for the type of motor from the Tables in Part XIV of Article 430.
The LRA only lasts for a short time and the conductors at the service should be able to withstand the LRA until the motor is up to full speed and the current drops to the running load amps.
Chris
LRA is not what you use when sizing service entrance conductors, feeders or branch circuit conductors.
When coming up with conductor sizing for a motor you will use the Tabulated ampacity for the type of motor from the Tables in Part XIV of Article 430.
The LRA only lasts for a short time and the conductors at the service should be able to withstand the LRA until the motor is up to full speed and the current drops to the running load amps.
Chris
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