Jim, ?interesting, and I get the jist, ?but I wonder what the point is. Anyhow, as I read stuff, #18 copper will melt [1000 C nom] at 83 amps yes ,but that happens in 10s , not 2 minutes. ?That would be the same heat/temp [ I^2 *t ] ?= about ??25A for 2 min. I don’t know when insulation turns to carbon, but I’m getting worried now. Maybe I goofed-up? And I have lost my point now too.? My past understanding was that grounding conductors were based on fusing temps, but conductors with insulation were somehow based on the insulation. I have no Idea what it can take short term.

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RE????? According to the above link, a 20 amp circuit breaker must support a 20 amp current but must trip at 200% of rated current within two minutes.??

Ya ,that is a most common criteria, and seems rather High. It seems that this was instigated back in fuse only days, and fuses that got too hot would get tired [flip on a big string of tungsten lamps] and fail.? Thermal elements of breakers also heat up in normal current service so in that condition it wont take so much to trip them, so the 200% is a practical number ?

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Re ?code in Britton? ?…????????? ?fuses in plugs

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…….诲辞苍

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