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#79466 - 12/28/01 10:34 AM Water heaters 422.11(F)(3)
Elzappr Offline
Registered: 12/20/01
Posts: 270
Loc: Oregon
I'm a little confused as to why the wording for subdividing loads to immersion resistance elements is considered to be "subdivided into circuits not exceeding 120A." This wording came into use in the 99 code. Other equipment usually uses the term "subdivided loads". I think of a 120A circuit as one that is loaded only up to 80% (96A), yet this section allows protection at 150A. I'm thinking that perhaps they intend that the subdivided "circuits" are to be rated at 100% (ie.,120A), but this seems like an obscure way to make their point. Would this whole thing have something to do with the allowable ampacity of wiring shifting from 60C to 75C table values when circuits are rated above 100A, per 110.14(C)? Or does this have to do with the fact that there will be fiberglass insulated wiring in the appliance and the subdivided circuit O.C. device would necessarily be rated for 90C use?
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