I just got back from a booster pump re-and-re. The new pumps are 3 25 HP 575V pump assembly with control - each pump is labeled with a 22.2A draw. The engineer drawings are specifying that we are to supply 3-#6 to the 3-pump assembly fused with a 80A time delay fuse. Looking immediately at table 13 - an 80A fuse is too large for #6 T90. Yet then there is 28-200(d) in the CEC. Here is my question - given that you can up a fuse size to 225% of the motor FLC if it does not start, does the conductor size have to be increased accordingly? It does not mention this a far as I can see in the CEC.
I realize on the face of it, that it appears the engineer didn't consult the code - I would size the conductor normally (22.2 * 1.25) + 22.2 + 22.2. = cable #4. It appears that one motor is a backup only and may not be used at all unless another is manually disconnected.
Last edited by Davo; 08/05/10 05:49 PM.