I was discussing code rules with another electrician and it involved an exam question from the ESAT Canadian Electrician Certificate of Qualification Practice Tool. The question was:
Q: What is the minimum size of AC90 cable that can be used to carry the maximum allowable electrical heating load that can be connected to a 240 V, 20 amp, 2-pole breaker?
A: Rules 62-114 and 4-006, Table 2, 75 degree column = #14 AWG
I have no problem understanding that breakers are rated at 60, 75, or 60/75 degrees (source: Schneider Electric) and therefore if the question only mentions "breaker" then you COULD assume 75 degrees for the termination temp. The problem is where in the code specifically does 75 degrees come from? If the termination temp of the equipment isn't specified (in this case, it's not specified in the question) then why would you assume the breaker's termination temp. is 75 degrees? It could be rated at 60 degrees. Poorly worded question or is the author of the question assuming you should know to use 75 degrees?
