Increased contact resistance in the breaker pole will manifest as excess heat from additional I²r loss. It may be too late to determine if the breaker has been taken out of service, but
in-situ AC millivolt-drop tests can sometimes flush out the problem. See
http://ecmweb.com/mag/electric_testing_contact_quality/index.html Also, with a little care—similar measurements can be made at the wire/load-side connection and main bus/breaker line-side spring-clip connection.
[This message has been edited by Bjarney (edited 07-26-2004).]
