Just using the table (430.250) as a starting point, I see a FLA of 27a times 1.25% gets you to 33.75 or 8ga wire. If you see #6 there it is because they think that compressor may be starting under a load and be looking at LRA or a significant portion of it, longer than you would normally assume, based on the article you posted.
They normally deal with this in air compressors by using an "unloader" that drops pressure between the tank check valve and the compressor. HVAC systems use a time delay to allow the head to drop so they are not trying to compress liquid refrigerant.
Appreciate your feedback Greg.
Here's better information on the numbers I used to calculate conductor size, voltage drop, and O/C protection based on the 2015 CEC:
- 3 PH
- 60 Hz
- INS. CL. "F"
- 1775 RPM
Min. Conductor Size
24.5A x 1.25 = 30.6A -> Table 2 -> 75 Celcius -> 35A -> #10
Table D3 -> Max run length for #10, 24.5A @ 120V = 6.2m
Distance correction factor -> Table 2 -> 75 Celcius -> #10 -> 35A -> 24.5A/35A x 100% = 70%
Table D3 (note 3 chart) -> % of allowable ampacity = 70% -> rated cond. temp. = 75 Celcius -> Dist corr. factor = 1.03
Max run length = 6.2m x 3(%) x 1.03 x 600V/120V = 95.8m
95.8m x 3.3'/m = 316'
Max O/C device rating (breaker)
Table 29 -> Max Setting Time Limit type CB -> 250% -> 24.5 x 250% = 61.3A
Instantaneous trip setting -> Rule 28-206(a)(b) -> 24.5A x 1300% = 319A
Motor Horsepower = 25HP -> Disconnect must be rated for at least 25HP -> Therefore suitable Trade Size Disconnect for 3 PH, 600V, 25 HP motor = 60A (Max 50HP)https://www.schneider-electric.ca/documents/electrical-distribution/en/shared/catalogue/DE2.pdf