On 12/02/2015 1:08 PM, Don Y wrote:
On 12/2/2015 11:54 AM, dpb wrote:
....

That's got to be a thermal problem in (probably) a particular
lamp...eventually
it'll burn out and let you isolate it or the base itself will fail.

Unplug the three strings from the extension cord. Leave cord
exactly as is. Take three *other* "identical" strings out
and wire them in exactly the same fashion as the first set-of-three.

Turn on breaker. Trips immediately. Let it reset and turn it
on a second time. Holds.

Walk around house to return to the point where the extension cord
is plugged in.

Unplug. Wait a few seconds. Plug back in. Breaker trips.

....

Hadn't seen the duplicated test result...

I'd stick with the thermal issue and I'd suspect the cord if it's one of
those w/ the indicator lamp built into the plug.

Did you ever isolate whether there were any other loads on this circuit
besides these two (I think were mentioned early on?) exterior receptacles?

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