I see enclousures with a single circuit breaker mounted in them and the handle operates left to right instead of up and down. There are no markings in the panel to indicate line and load. If the contractor installs the load conductors on the top side of the breaker and the line conductors on the bottom of the circuit breaker is this a violation? Manufacturer is silent on this matter. I asked the contractor to use a magic marker to label line and load and he agreed.
Check 408.16(F) back fed devices. Switches and breakers used as switches must also be indicating, i.e. off /on if not verticle. 404.7 I think these references are the ones you need. Alan-- Just reread the question...same references plus UL listing. Is he using a double pole breaker with line on one terminal and load connected to the other half ????? When the breaker is off it is still energized. Why does he use an enclosure instead of just wrapping tape around the bomb he has made. Alan--
Alan- Bob is correct, the CB is being used like you'd use a safety switch. There were no Line/Load designations. The terminals were on the top and bottom of the CB and the handle operated horizontally. I asked the contractor to label Line/Load with a marker, which he did. If I were the installer, I'd mark it for my own benefit because you'd probable not remember Line/Load when you went back to it in the future. The panel was flush in the wall and there was no way of knowing which way the conductors were coming from. As it turned out the top side of the breaker was being used as the Load and usually the top side is the Line.
I've seen this discussion somewhere else, possibly in the IAEI magazine. The consensus of the discussion was that if there were no markings on the breaker or the enclosure, the line could be connected to either end. This is in agreement with what is in the UL White Book (DIVQ) last sentence of the Installation paragraph "Line and load markings on a circuit breaker are intended to limit connections thereto as marked."
Asking the installer to identify which end is the line connection is an excellant idea and sounds to me like a possible proposal for the 2011 NEC.
Few things are harder to put up with than the annoyance of a good example.