....
:
: It should be noted that the 60 amp circuit that supplies power
to the
: subpanel for the room addition had been turned on over six
weeks ago
: and had operated flawlessly until this afternoon.
:
: Any one of the single pole breakers tripping would just be an
anomaly
: that would not need to be answered unless the problem recurred.
But
: the 60 amp double pole breaker tripping under no load has
caused my
: friends some concern.
:
: Can anyone think of a circumstance that would cause the
problems that
: they experienced?
:
: TIA

All the "testers" in the world, great as they are most of the
time, are only as good as their design and the users.

I'd say it's time to put the testers away and get down to some
real world troubleshooting with eyeballs and good old analog
meters after eyeballing what's about to be measured.
I just got thru with a 4-trip "fix" for a battery discharging
problem in my Buick. They pronounced it fixed each time I picked
the car up. It wasn't, and it took me all of about 5 minutes to
get out my Triplett, disconnect the positive terminal of the
battery, and see in excess of 3 Amps flowing with everything
turned off and the doors closed. But it tested perfectly every
time on their "tester". It's $650 later right now, it's fixed
finally, and I'm waiting for them to respond to see if I take
them to small claims court or they drop the phoney fixes that
weren't fixes, thanks to their computer diagnostics et al.

I have no idea what your source of the problem may be though.
Can't see it, and wondering if the testers are doing what they
need to do in this particular case.

HTH,

Pop