How to properly size my wire?

[electricalRookie]

hi all

I have a 5000KVA transformer that converts 480V to 120V. The 120V side is mainly heaters controlled by PLC.

I picked a ~50A breaker based on 5000/120*1.25 (I assume they are all continuous load although the heaters won't be running all time when they reach their target temperature). Should I use 8awg wires (good for above 50 A)or 10awg wires (good for 30A?) for this project since my heaters won't be running all the time once they reach their target temperature

 

[AC\DC]

How would #10 even be feasible????

 

[winnie]

I assume 5000VA not 5000kVA

In general wire must be protected at its ampacity unless you have a specific load identified in the CEC permitting use of a breaker larger than the ampacity of the wire.

So barring a specific permission, if you use a 50A breaker you need a 50A wire.

Your profile lists you as a student in Canada. Does the above give you enough info to go through the CEC and work out your answer? Few here know the CEC in depth so you will probably need to post your answer with code references.


Jon