11-13-2014, 08:34 AM
I am not sure, and don't have the records handy to check, but one reason for the difference between US and Canadian wire type, rubber covered vs. cloth covered, could be a difference between UL and CSA requirements at the time. Having dealt with both, I know that CSA requirements are sometimes different and more conservative, even to this day. This might be an interesting bit of trivia for someone to investigate.