hello, i would like to answer your question
are you still online
Hey GeorgeDuct tape will catch on fire only with direct flames. In indirect flames, it can handle temperatures of up to 200 degrees.
Is there a serial number or model number for the supply box? I would like to know how much heat that could that box could genearate. Duct tape on the insulation will be fine, it will not be a fire hazard. Thanks