On Friday, December 4, 2015 at 10:10:29 AM UTC-5, Don Y wrote:
On 12/4/2015 7:11 AM, wrote:

A partial short between the ground and the neutral in the extension cord or
elsewhere could cause the OPs symptoms.

What causes it to *heal*? And also reappear?

"Cold flow" from a neutral conductor to case can likewise cause load-related
GFCI trips. But it doesn't "recover" and also "recur" -- not in a matter
of tens of seconds.


If it is a partial short from neutral to ground, the GFI will trip only when there is a large current flow, for example during the turn on surge of cold bulbs.

If even a small percentage of the current flows through the ground, it will trip the GFI.