Mike Stewart
Member
Can someone help me understand this article, the way it is being explained is that for every "hot" you have to have a neutral, or you can install a three pole breaker, have three hots and one neutral.
The engineer is on record is wanting to use breaker ties but the customer engineer says two more neutrals have to be installed so that all three hots has its own neutral. Our local inspector says it refers back to this code but I guess I am not fully understand the code.
GasIf MWBCs ever become 'illegal', I don't know what we'll do to supply power to all these residential electric ranges, cooktops, ovens and clothes dryers.
Or a house.If MWBCs ever become 'illegal', I don't know what we'll do to supply power to all these residential electric ranges, cooktops, ovens and clothes dryers.
Take your pick, all three are allowed.But is it required to use either the three hots with three neutrals "or" a three pole breaker or single poles with a breaker tie?
Poor examples of the MWBC the OP is referring to. Those are two pole ckts to individual UL listed units which MUST be run on two pole breaker, no exceptions (residential), maybe three pole for commercial.If MWBCs weren't allowed any more, they would have been written out of the Code. But clearly, they're still there, so they are allowed.
210.4 merely states how MWBCs are to be handled.... it doesn't say you can't have them.
If MWBCs ever become 'illegal', I don't know what we'll do to supply power to all these residential electric ranges, cooktops, ovens and clothes dryers.
Poor examples of the MWBC the OP is referring to. Those are two pole ckts to individual UL listed units which MUST be run on two pole breaker, no exceptions (residential), maybe three pole for commercial.
Actually those are good examples of MWBC's regardless of what is connected to them.Poor examples of the MWBC the OP is referring to. Those are two pole ckts to individual UL listed units which MUST be run on two pole breaker, no exceptions (residential), maybe three pole for commercial.
3 ungrounded and 3 grounded conductors sounds more like 3 regular circuits than a MWBC. One of the main reasons for a MWBC is to save on wire. If the 3 ungrounded conductors are feeding different outlets why not just use 3 individual breakers? I wouldn't want one circuit tripping and shutting the other two down. IMHO!
Actually those are good examples of MWBC's regardless of what is connected to them.
Roger
Take the dryer for example, it utilizes a two pole MWBC and can use handle ties or a multi-pole breaker, a "two pole" breaker is not mandatory for this circuit, see 240.15(B)(2)Poor examples of the MWBC the OP is referring to. Those are two pole ckts to individual UL listed units which MUST be run on two pole breaker, no exceptions (residential), maybe three pole for commercial.
Can a MWBC be tied to a 15 amp and a 20 amp ckt breakers ( utilizing handle ties), if 12 awg is used?
Yes.