I-Line™ circuit breakers, I-Line™ busway plug-on units, I-Line™ panel boards and switchboards, QMB plug-on switches and motor control center plug-on units are supplied with factory applied joint compound on the plug-on connectors. The compound should not be removed because it contributes to the overall performance of the connection. Whenever one-of these units is removed and reinstalled, the joint compound should be reapplied. Catalog# PJC 7201 is a 2 oz container of compound specially formulated for the I-Line™, QMB and motor control center connections. No other type of commercially available joint compound should be used.