I'm trying to wrap my mind around how many amps 220V wire (two hot poles) can supply, when it's effectively supplying a multi wire branch circuit (sub panel)…
My question is this:
if the sub panel is supplied by a single 60 amp two pole (220v) breaker (4/3 wire) circuit, can I (theoretically) put in two 60 amp single pole breakers in the sub panel (one for each pole), effectively making a multi-wire branch circuit within the sub-panel? Or, should I understand that the sub panel can only support up to two (theoretical) 30 amp 110v circuits?
thanks so much!
Best Answer
Jeffrey is correct. You will have 60 amps of 240 volt power available.
As to the use of single pole breakers for a multiwire branch circuit, that is a code violation unless the breakers are tied together with a handle tie from the manufacturer. You can't use tie wire, a nail, or any other unapproved method. Better yet, you can use a common trip 2 pole breaker. This is the preferred method.
Informational Note: 110 and 220 volts are not normally available now. The voltages keep moving up. Most equipment is now rated for 125 and 250 and the National Electrical Code lists 120/240 or 120/208 as the nominal voltages for dwelling units.