TW #4 awg copper SE Rated ? yes/ no ? or at sometime in the past 1950`s ?

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cocodrilo

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looking at table 310.15(B) conductor types and sizes for 120/240 vac 3 wire single-phase dwelling services and feeders, conductor types list evrything but TW, that is for the 2011 and 2008 NEC and going back to the oldest NEC I have 1996 same code section there is no TW types mentioned .

I have seen SF homes dated or later (1959) where they installed #4 TW copper for the service entrance and feeders and protected at 100 amps, but I cannot find that rating for the TW # 4 copper. Table 310.15(B)(16) list #4 TW copper 60 degree C. at 70 amps.

Does anyone know what year or exception that this was alloowed?
 
I don't think the table has ever included any 60C conductors. All of the conductors are 75C or 90C rated.
 
TW #4 cu used as S.E. and feeder conductor 1959 and 1960 for single family dwellings

TW #4 cu used as S.E. and feeder conductor 1959 and 1960 for single family dwellings

I have come across homes with this TW 4 cu on 100 amp main ocpd, but table 310.15 (B)(16) rates this wire at 70 amps/60 C and the other table:

310.15(B)(7) for 2011 NEC or earlier for single family dwellings 120/240VAC - 1 PH. never has included TW as far back as NEC 1996

I cannot find any info allowing this conductor at that amperage. (100 amps ocpd main breaker)?
however I am seeing homes in South Florida with this service. definitely out dated, I guess...
 
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