Good summary explanation by DeaneG, except for the 75%. As garygid points out, it is 80%.
Confusion arises partly due to the 80%, which, unless it is specifically referenced, causes trouble especially for the 30A number, because the breakers are rated in 10A increments (except for the lowly 15A single pole). So, the 30A breaker should be used to supply 24A, not 30A. In order to make use of the 30A continuous current you DO need a 40A breaker, but the actual allowable current is 80% of 40 = 32A. I have even seen erroneous references to the 30A draw in connection with some J1772 equipment. But the J1772 does not have a pilot signal for 30A ... the signal is 32A (as it should be, and in which case, gues what, it should sit on a 40A breaker).
(More confusion: many receptacles and plug have a maximum rating of 250V printed on them.)
My house is "overvolted" ... we share a transformer with only one other neighbor. Even under load my "240V" (nominal) supply runs 242V in the mornings and 247V in the afternoons. I have seen as high as 249V, but rarely. I have seen open-circuit voltages (volt meter, no load) on the "120V" (nominal) as low as 115, but usually running 119-122V.
edit: Note: I am getting all sorts of conflicting info in researching about the 30A versus 32A pilot signal in the J1772 spec. (Also see my reply a few posts down.)
Last edited by LEAFer
on Sat Jun 19, 2010 9:17 am, edited 1 time in total.
2011 Silver SL+QC [Mfg: 11/2010] 36mo/15k LEASE
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