E/F relay suitability

[hallmg]

Hi,

We are planning to use a spare feeder to supply a compressor motor (see attached drawing)

The feeder panel has an earth fault relay already fitted, which has a CT on each phase and on the neutral.

The compressor motor only has three phases and no neutral.

The question is can this existing relay be used with the CTs as they are or can they be reconfigured or would it require a different relay all together?

Any help would be much appreciated.

Melvin.

 

[ScottyUK]

The E/F relay would work as shown, or you can disconnect the neutral CT from the group and short the CT secondary terminals.

What are you intending to switch the motor with, and what are you going use to protect it against thermal overload etc? That elderly M-Pact breaker isn't exactly intended for motor duty and whatever overload it has internally (dashpots?) will be a lousy match to the motor's thermal curve. If you're using it as a feeder to an external starter then it is OK in principle.