First off, let me say that motors are my personal area of weakness.
Knowing that they are my area of weakness, I’ve tended to try to avoid them.
However, I have a small job now for an existing customer, that I think would be a good job to review motor basics as covered by the CEC.
The customer has a small shop and wants to hook up a compressor.
The compressor is 240V and the nameplate says 15A.
The compressor has a thermally protected motor and an on/ off switch.
The panel feeding power is an old one with plug fuses and is within 9m of the compressor.
Because the compressor has a switch and is thermally protected, I can just feed it with 12/2 and fuse it between 20A up to a max. of 45A.
Correct?
Now some confirmations please relating to motors.
If the compressor didn’t have a switch, then I would need a disconnect switch. A 20A DPST switch would work for this purpose. Correct?
If the compressor didn’t have a switch but the circuit was fed through a breaker panel, then would the circuit breaker count as the disconnect switch?
If the compressor motor wasn’t thermally protected, what would be the most cost effective method of providing this?
Thanks in advance. Sorry for the long post.
Bruce
