I recently bought a 18,000btu mini split unit. Compressor load is 12.3A, minimum ampacity is 18A and max fuse is 25A. My plan was to use the existing dedicated circuit that powers the electric baseboard heaters for the mini split (disconnect the baseboard heat completely). I expected the existingwiring to be at least 12/2 with a 20A breaker but it's 14/4 with a 15A breaker. (240v double pole). The installation manual that comes with the mini split says minimum gauge for 18A is 14. So my question is as long as the breaker remains 15A can I use the 14awg or do I need to run a whole new 12awg circuit with 20A breaker. And is it likely the cb will constantly trip? My understanding is a mini split unit rarely draws up to its min ampacity and when it does it's only a very short duration. A new dedicated line would require a complicated outdoor path or tearing into some walls so if possible I would like to avoid that . Thanks for any advice.
- posted 2 years ago