Temp Rise of an Insulated Copper Wire 1

[madddog]

I need the equations that define the temp rise of a #10AWG insulated wire carrying 11.23 amps.

I am designing an 10,00ft umbilical cable that will power two 150HP electric pumps. The heat rise per foot will determine the maximum number of layers on a cable reel, ie overall reel size.

Thanks

 

[jbartos]

Suggestion: Visit

http://www.bergquistcompany.com/objects/Tclad_SelGuide_PDFs/Selecting_A_Circuit_Layer.pdf

http://www.rogers-corp.com/mwu/pdf/rt332.pdf

http://www.tpub.com/neets/book4/11m.htm

etc. for more info

 

[jghrist]

There is no simple equation that I know of. The heat rise depends on the thermal resistance between the conductor and free air, that is, the resistance to heat conduction from an inside conductor through various layers of cable insulation and shields. Also on the mutual heating of the other cable layers. Maybe someone has studied this situation and has come up with some empirical equations.

You might be able to get some help in "Rating of Electric Power Cables," G.J. Anders, IEEE Press, 1997.

From the load (300 HP) and amperage (11.23A), it appears that you will operating at 15 kV. The diameter of No. 10 AWG is too small for 15 kV; the voltage stress will be too high close to the conductor. Generally, No. 2 AWG is the minimum size for 15 kV.

 

[madddog]

Thanks jbartos

Your second link helped but also confused since it relates to PC board copper runs. I need a solid reference for this problem.

Anymore help would be greatly appreciated.

 

[jlhmaint]

http://www.mddesigns.com/mustang/Reference/wiresize.pdf

 

[jlhmaint]

http://www.bussmann.com/library/docs/Spd.pdf

 

[jlhmaint]

I am with jghrist what voltage are you running a 150HP motor at to get 11.23amps with 2 of those motors.

 

[jbartos]

Question: Is the cable made of copper or aluminum?

 

[jbartos]

Suggestion: Reference:
1. IEEE Std 399-1997 IEEE Recommended Practice for Industrial and Commercial Power System Analysis,
Section 13.4 Ampacity Adjustment Factors,
Pages 388-399 for Ft = ambient and conductor temperature adjustment factor, i.e.
Ft={[(Tc' - Ta')/(Tc - Ta)]x[(234.5 + Tc)/(234.5 + Tc')]}**0.5;
(for copper conductors)
where
Tc is the conductor rated temperature in deg C at which the base ampacity is specified;
Tc' is the maximum allowable conductor temperature in deg C;
Ta is the ambient temperature in deg C at which the base ampacity is specified
Ta' is the actual (maximum) surrounding (soil) ambient temperature in deg C.
(Change 234.5 to 228.1 for aluminum conductor.)