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Derating SOW Cable

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dinkelja

Electrical
Dec 10, 2004
31
Does anyone know, in general what NEC section (table) best describes how to derate SOW type cable. I am unable to verify voltage drop calcs. The application is for (temporary) power disto from smaller portable generators (15kw). The cord reels are specified with 200' SOW cable, 3wire+G #10AWG "split" single phase, 240V. The continuous load is one 1.5 hp 230V motor (10A), and two 750W-120V lights, one per leg. When we say 10A @240V single phase, we mean 10A per wire correct? Ambient 30degC. Just looking for less than 5% on the 230V motor. No electronics so the overall circuit VD doesn't concern me. Would anyone be able to calc if they know? I find about 8.1V with 16.25A load. Say the neutral caried both 750W lights, is it necessary to derate further if it carries a net current? Thanks, JD (EIT).
 
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I guess I'm okay with the ampacity and voltage drop. I am concerned that we probably will not have all of it off of the reel at once. Meaning that it will have to dissipate whatever fraction x 250W is wound around the reel. Could this prove to be a problem, opinions? Full load operates for about 30 minutes. I think we'll try to get SJOW, 90 deg insulation too.
 
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