- Joined
- May 20, 2017
- Messages
- 162
I am going to be building my first RPC soon, and I have a stupid question. I have a 3 pole fuse block for power to go through on the way out to the machines. If the equipment motor is ten amps, do I use 3 ten amps fuses, or does the ten amps get divided between the 3 lines?
Also, I bought a lot of used electrical boxes at auction, and one of them had some volt meters on it. Would there be any benefit to wiring these in to see real time volt readings while the equipment is in use?View attachment 278950
If you believe NEC Table 430.52, you need 175% of the FLA with time-delay fuses or 300% of the FLA with non-delay fuses, or for a 10A 3 phase motor, either (17.5A) 20A, or 30A. Start-up current for small AC motors is 6X FLA, and that is unloaded. 10A fuses are likely to blow. You do not say what your voltage is, but the meters shown appear to be 500 V full scale and you probably would not be able to tease out important differences between the 3 phases. Current would probably be the more useful parameter to monitor. However, if you are going for the Mr. Carlson's Lab look, it does look slick. The conductor to the motor should be 125% of the motor FLA, or 12.5 A, so you could use 14AWG.