Strombea
Senior Member
- Location
- Prescott, Arizona, USA
We install alot of hood contactor and captive air systems and on the last one I used a MWBC to feed the 2 fans on the roof- 1 exhaust 120v fan and 1 swamp cooler blower only 120v fan make up air. The captive air box has the 2 contacts set up for hot and neutral. i only used hot T1 terminals as I was sharing neutral.
problem: when we fired up the swamp cooler it ran fine until we turned on exhaust fan, I cant figure out how or why but it seems like the exaust fan is some how priority and is stealing the neutral path.
Could phasing to building be messed up? maybe B phase isnt 180 degree offset?
any way i gave the swamp cooler its own neutral from buss and it works fine now, just stumped on the MWBC should share a neutral.
All wire is THHN #12 and sq d QO 20 double pole breaker feeding MWBC
problem: when we fired up the swamp cooler it ran fine until we turned on exhaust fan, I cant figure out how or why but it seems like the exaust fan is some how priority and is stealing the neutral path.
Could phasing to building be messed up? maybe B phase isnt 180 degree offset?
any way i gave the swamp cooler its own neutral from buss and it works fine now, just stumped on the MWBC should share a neutral.
All wire is THHN #12 and sq d QO 20 double pole breaker feeding MWBC