At 10:51 PM 7/16/01 -0400, Robert E. Griffith wrote: >Wait a minute; maybe I just figured it out. When there is load on both >circuits, if the circuits are 180 degrees out of phase then the current on >the common neutral would tend to cancel - creating a smaller current load on >the neutral wire. If they were in phase, the current on the neutral would >be the sum of the two circuits so it would have to be rated for the sum of >the two circuits (30-amps). Is that it? Got it exactly! >Here's a somewhat related question. In my basement, I have a chop saw on a >15-amp circuit that blows occasionally when the saw starts. If the wire on >this circuit is thick enough, can I replace the 15-amp breaker with a 20-amp >breaker? What gauge is rated for 20-amp? My first attempt at fixing this would be to pull heavier wire to the saw but staying with the 15A breaker. Here is why: if the wire is too small, the voltage at the saw is too low and the saw takes too long to come up to speed. The breaker will handle surge currents only for a limited amount of time. Because the saw is still drawing too much current when that time limit is up, the breaker trips. 12 AWG is the standard wire size for 20 Amps. But in your case, I'd try pulling 10AWG wire in. If the 15A breaker still trips, then go for the 20A breaker. But the heavier wire may just fix the problem. dwayne Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 17 years of Engineering Innovation (1984 - 2001) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads