10A.4. Current-carrying capacity of wire. A copper wire of 0.040 in. diameter is insulated uni- formly with plastic to an outer diameter of 0.12 in. and is exposed to surroundings at 100°F. The heat transfer coefficient from the outer surface of the plastic to the surroundings is 1.5 Btu/hr ft F. What is the maximum steady current, in amperes, that this wire can carry without heating any part of the plastic above its operating limit of 200°F? The thermal and electrical conductivities may be assumed constant at the values given here: k (Btu/hr.ft.F) k (ohm ¹ cm ¹) 220 5.1 X 105 0.20 0.0 Copper Plastic

10A.4. Current-carrying capacity of wire. A copper wire of 0.040 in. diameter is insulated uni- formly with plastic to an outer diameter of 0.12 in. and is exposed to surroundings at 100°F. The heat transfer coefficient from the outer surface of the plastic to the surroundings is 1.5 Btu/hr ft F. What is the maximum steady current, in amperes, that this wire can carry without heating any part of the plastic above its operating limit of 200°F? The thermal and electrical conductivities may be assumed constant at the values given here: k (Btu/hr.ft.F) k (ohm ¹ cm ¹) 220 5.1 X 105 0.20 0.0 Copper Plastic

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.21P

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