Someone I met in 1992 had a problem ITE interchangeable style breakers spitting and popping because the busbar jaws would overheat and loosen. Measurements of a lighting circuit ( four 400 watt mercury vapor fixtures ) that ate breakers showed that the busbar jaws of a 20 amp circuit breaker could not carry 11 amps. The ballast type was constant wattage autotransformer.

After Ilsco Deox passed the 3-year salt spray test on the starter motor on my car and SquareD started using grease on the jaws of their I-line circuits breakers, I did an easy repair for him. I turned off the 200-amp main breaker, pulled all of the breakers from the bus, cleaned crud off of the busbar tabs, greased the busbar tabs with Ilsco Deox, injected each breaker jaw with Deox, put all of the breakers back on. Has worked fine since then. In 1991 or 1992 I met an electrician who had done the same thing with 4 ITE 200-amp panelboards.

SquareD seems to have been bery wise to start putting part number PJC-7201 grease on the jaws of their I-line and QO circuit breakers. This grease also allowed them to get rid of the Q1 frame size breakers as well too.

Mike Cole mc5w at earthlink dot net