I have two kitchen lights controlled by two three way switches. The CB trips on this circuit. I thought we had a bad CB but the new CB also trips. I noticed one of the two lights was on before the new CB tripped. No work has been done on this circuit for many years. Any ideas what might be causing the CB to trip?
Insulation may have biodegraded or become brittle due to light bulb heat, and flaked off the wire. Then the wire touched something it was not supposed to touch and a short resulted.
You will have to find where any problem might be, it could be in an outlet box other than where the light in question is or where the swithces controlling the light are.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.