Motor circuit design

[Ben Grant]

Got a 3 phase extractor fan circuit run off inverter. 3.5kw machine 6.5A. Cable run below 15 meters, so am running a 2.5mm 3 core swa as no neutral needed. Someone mentioned a 32A 3 phase breaker type D but that's too big. 20A type D 3 phase is the one to use? Did the man simply quote the wrong breaker size?

 

[netblindpaul]

Where are you putting the mcb, before or after the inverter?

 

[plugsandsparks]

Suggest consult inverter installation instructions, usually off the net

 

[Knobhead]

Where ever the MCB is fitted it's too big.

See where your heading with this Paul

 

[bomjac]

Should also have overcurrent protection to the motor end of the circuit. Anything > 0.37kW requires it.

 

[Knobhead]

Should also have overcurrent protection to the motor end of the circuit. Anything > 0.37kW requires it.

It will be built in to the inverter.