Re: Two dedicated 20 AMP Circuits...
First, I was paraprashing art 100. I was trying to be descriptive and tell what a MWB is. Unfortunately, that backfired.
A MWBC is a complete entity in itself, however, it is made up of 2 individual circuits. The loads on one circuit are not affected by the loads of the other. One can be turned off with out the other being turned off (unless same yoke, or supplying line to line loads).
Therefore when installing the circuit, you would treat it as one singular item. Yet when it comes to protection, we still treat them individually. You could have a 20A breaker and a 15A breaker protecting 2 different types of loads on that same MWBC, but still they are each their own identity.
Wbalsam1, I don't understand what you are saying with this reply
Also note that NEC 2005 at 240.20(B) requires circuit breakers to open all ungrounded conductors of the circuit both manually and automatically. Handle-ties do NOT cause a common trip.
240.20(B) states that they shall open both
manually and automatically, unless otherwise permitted in 240.20(B)(1), individual breakers with or without identified handle ties...
What is your point? Manually means that it needs to work by hand, and automatically means that it needs to work automatically. There is nothing stated about internal, or common trip. A handle tie trips the other breaker if one breaker trips, automatic. If you turn one off, the other will turn off, too, manual.
It doesn't say anything about common trip. Handle ties are there to provide both themanual and automatic.
Also, 210.7 states for multiple circuits on same Yoke (MWBC or not) that a 'means to simultaneously disconnect'. That does not mean internal common trip, either.
I can't find any where that it tells you that you CAN use a 2pole breaker for 2 individual, line to neutral only, circuits. I do see several things that tell me how and where I can use individual breakers, though.
