Repeat Prob. 17–88E, assuming a thermal contact resistance of 0.001 h·ft²·°F/Btu at the interface of the wire and the insulation.

Data from 17-88E.

A 0.083-in-diameter electrical wire at 90°F is covered by 0.02-in-thick plastic insulation (k = 0.075 Btu/h·ft·°F). The wire is exposed to a medium at 50°F, with a combined convection and radiation heat transfer coefficient of 2.5 Btu/h·ft²·°F. Determine if the plastic insulation on the wire will increase or decrease heat transfer from the wire.