mutiwire circuit

[reyamkram]

can I use 3 120v single phase single pole breakers on 3phase 120/208 v, to run 3 different machines 120 aux equipment, so if one shorts out or overloads,
the other machines will not shut down, or do I need a 3 pole breaker

I can run 3 hots and one netural.

 

[augie47]

A couple of points come to mind right off. First, if you are sharing a neutral you will need to assure simultaneous disconnecting of the breakers by using a 3 pole breaker or listed handle tie. Secondly you will need to mark the equipment as having power fed from more than one source.
I will have to study a bit on the 3 one pole breakers but with the simultaneous disconnect it might be a mute point

 

[kwired]

can I use 3 120v single phase single pole breakers on 3phase 120/208 v, to run 3 different machines 120 aux equipment, so if one shorts out or overloads,
the other machines will not shut down, or do I need a 3 pole breaker

I can run 3 hots and one netural.

three hots and one neutral, you can run three single pole breakers, but you still need handle ties so that if you shut one off they all shut off. Such handle ties still allow one breaker to trip without tripping the others, but to reset it you will still need to shut them all off.

 

[gar]

170409-1632 EDT

I find the question very unclear.

Are there three totally independent machines powered at single phase 120 V each, no 3 phase at any of the machines, or are there three machines all requiring 3 phase power, connected to the same circuit, but also each machine has some 120 V loads line to neutral?

.

 

[kwired]

can I use 3 120v single phase single pole breakers on 3phase 120/208 v, to run 3 different machines 120 aux equipment, so if one shorts out or overloads,
the other machines will not shut down, or do I need a 3 pole breaker

I can run 3 hots and one netural.

170409-1632 EDT

I find the question very unclear.

Are there three totally independent machines powered at single phase 120 V each, no 3 phase at any of the machines, or are there three machines all requiring 3 phase power, connected to the same circuit, but also each machine has some 120 V loads line to neutral?

.

I think three different 120 volt machines.

 

[JFletcher]

You can use handle ties in lieu of a 3p breaker. If you can run separate neutrals, you will not need ties, and each 120V circuit can be completely independent of the others, and that may be advantageous depending on how far away the equipment is from the panel, how often you need to do LO/TO for maintenance, how critical it is to keep one or more machines on line simultaneously, etc.

as augie mentioned, if it isnt already there, the eqpt may need signage like this: