"PipeDown" wrote in message
nk.net...
It should trip both sides but by virtue of the handle not anything inside.

Each of the two legs of the main breaker feeds some 220V loads but most
are split up between the 110V circuits.

What troubles me is that you have a 110V load tripping the 60A main but
not any of the 20A breakers before it. So if it is not the dryer or range
tripping the main, then you may have at least one 20A breaker that is
defective or you are just drawing more than 60A divided up between at
least 3 or 4, 20A branches on the same side (phase)

If you do have an electrician look at it, ask him to rearrange the
breakers (WRT the phase they are plugged into) so that the loads are
better balanced.
..
Small point; although the word 'phases' is sometimes used most likely they
are not?
Most likely Leg A and Leg B being the two 'ends' of a typical North
American 220 volt single phase 3 wire (110 - 0 -110) service?
BTW either an overload on one 'side' (leg) or a bad connection somewhere?
Possibly a corroded meter socket; not uncommon in our maritime climate?
Do not leave unattended!