On Wed, 20 Jan 2016 12:21:41 -0700, Don Y wrote:

And, it's NOT a GFCI circuit? And, it's a 120V line?

Is the breaker a single breaker? Or, a "dual" (though NOT 220V)?

I have no idea what the circuit is yet, but it has at least three
built in switched lights on it.

It's a single breaker (not ganged), but it seems to be in a dual package.

Here it is in the off position (top right, 4th down, 15 amp).
http://i65.tinypic.com/i5692c.jpg

Here it trips the instant I try to set it to on.
http://i66.tinypic.com/2ec2kol.jpg