“Multiple installers have mentioned that I will need a 40 amp breaker with 10 gauge wiring”

Multiple Installers, meaning HVAC Contractors? why not get an licensed Electrical Contractor or does the HVAC Contractor sub out the electrical part to a Electrical Contractor who knows the codes in your country and providence, don’t they have to be required to attend class every couple years to keep up with code changes like what plumbers and electricians in the USA have to do?

I mean can a HVAC Tech. in your country legally actually open up a main distribution panel to install breakers or run wires from the breaker panel to the outdoor disconnect or is that a job for only a licensed Electrical Contractor and Electrical Journeyperson can do?

What does your town electrical permit department have to say, and is a permit required to install this system?

 

Yes I'm referring to HVAC contractors or techs (I've updated my post accordingly). In Canada HVAC techs almost always take care of the electrical portion of the install, including installing breakers and running wire.

Thanks,
Harry

 

yes, the system falls under multi-motor assemblies. manufacturer has already done the calculations and listed them on the side of the unit. wire is sized based on minimum ampacity, and breaker based on max overcurrent protection. the sizing you mentioned, is for general use circuits, like receptacles for bedrooms, so 20amp or 15a recs would be on a 20 a max circuit with 12 ga wire.

 

I'm not sure how it works in Canada, but we have interesting code "variations" when it comes to mechanical AC equipment. It's pretty simple, but there was a time when almost no HVAC techs or installers understood the code for an electrical feed for the AC. Nowadays more know and understand what is going on. You already stated it in your OP.

Wire is sized to the minimum, breaker sized to the max, it's stated on the nomenclature tag on the unit. Now here is the why of it:

The electrical code does not regulate (or have control over?) the electrical in the AC. The AC is regulated by Underwriter Laboratories. Every single component in the AC needs to pass UL scrutiny, make no changes to the equipment and you're cool. Once you start modifying the AC, then you assume the liability.

 

Mike Holt is the guru when it come to electrical. Here's a vid that better explains what I was saying in the post above. He also cites the actual code(s) and explains in enough detail that you'd be able to calmly explain it to any inspector who may question what you are doing. At least, in the USA. LOL

Does Canada follow the USA regarding electrical codes? Or do they have their own code book?

 

Pros, we are getting too deep into technical issues in this thread that his contractor should be able to figure out.

Even if he isn't DIYing this, any google search will bring up this discussion.

Thanks for your understanding.

 

I don’t know about the CEC, and haven’t taken a class for the NEC (American) for a while but as I recall there is a section of code that covers this.