In article , JeffB wrote:

Questions:
1) Is is permissible to run 120V and 240V circuits off the same pair of circuit
breakers - if they are ganged together?

No.

2) If breakers are ganged together, and one leg is overloaded, are they both
supposed to trip?

Yes.

I performed a little test:
a) with the two breakers separate, an overload (120V) visibly trips one breaker
- the handle moves to the off position.

That's good.

b) with the two breakers ganged together, the same overload internally trips
the same breaker, but the handles don't move, and the other breaker remains live.

That's bad.

Is this proper behavior? Turning the breakers off, the on again resets the tripped
breaker.

No. Kinda defeats the purpose of ganging them together, doesn't it, if they
don't *both* move when *one* is tripped?

3) Do breakers 'wear out' or degrade over time? One reason I want a 240V
circuit is I'm experiencing nuisance tripping when running my table saw under load.
Is it possible that the breaker is just tripping prematurely?

Yes, they do wear out, particularly if subjected to repeated overloads.

4) Should I just leave the the whole existing mess alone, get an upgraded power
drop, main panel and add 240V circuits? This option is MUCH more expensive...

You could get a pair of half-height duplex breakers; that would enable you to
run two 120V and one 240V circuits in the same physical space as the two 120V
breakers you now have.

I was looking for the NEC online, but it looks like I have to buy a copy, or
see if the library has one...

Yeah, they don't make it available for free. The library is a good bet; lots
of bookstores have it; and they're up for sale on eBay all the time too.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?