Forums » Electrical Engineering

3 pole breaker Vs 4 pole breaker

    • 9 posts
    July 15, 2020 1:31 PM PDT

    what is the regulation requirement regarding 3 pole and 4 pole breakers with their application? Where and when to use 3 pole or 4 pole?

    • 160 posts
    July 15, 2020 2:20 PM PDT

    3 pole breakers are used with 3 phase equipment.  A 4 pole breaker would be for a 3 phase piece of equipment that needed a  switch neutral.  The 4th pole on the breaker is for the neutral.  There may be other systems I am not aware of that may use those breakers differently.

    • 9 posts
    July 15, 2020 4:29 PM PDT

    Thank you Dennis. why and when it is needed to switch off the neutral?

    • 160 posts
    July 16, 2020 4:25 AM PDT

    I believe gas pumps used to be required to disconnect the neutral but I am not certain what else.