I am dumbfounded with an issue. The following are the specs.
New Eaton Panel with 3P 200a MCB 277/480
Breakers are mostly a mix of 3 poles for 480v AHU Equipment.
The 1-3/20 breaker feeds a humidifier is giving me trouble.
When breaker was initially turned on we read 480 across phases and 277 to ground. All is good.
When the Mechanical contractor turned on the disconnect at humidifier the problems started.
Phases A&B where good however C phase dropped to 57 volts. Between A&B still read 480 but AC & BC were way out of whack. I don't remember exact voltage reading but something like 240 AC and 140 BC.
I assumed it may have been a bad breaker. Luckily we had a spare 3p/20 so we replaced.
Well I took readings again once we re-energized panel at the 3/20 breaker and everything was normal when no load was present. Again they closed the disconnect at humidifier and powered the unit up. Again the same exact issue. We "exercised" the replacement breaker and even intentionally tripped it to see if "something internal" would reset. When turning back on (without any load and disconnect open) we still only got 57 volts on C phase which again tells me this breaker is now bad too.
Obviously these breakers are not cheap and we cant just try another breaker.
Has anyone else had this problem and if so what was your solution? I personally think something in the humidifier is doing this to the breakers. They are not tripping and the 3 pole breaker opposite side is all good with 277/480 readings so I know its not the buss. All other breakers in panel above and below are working normal.
All suggestions welcome.
New Eaton Panel with 3P 200a MCB 277/480
Breakers are mostly a mix of 3 poles for 480v AHU Equipment.
The 1-3/20 breaker feeds a humidifier is giving me trouble.
When breaker was initially turned on we read 480 across phases and 277 to ground. All is good.
When the Mechanical contractor turned on the disconnect at humidifier the problems started.
Phases A&B where good however C phase dropped to 57 volts. Between A&B still read 480 but AC & BC were way out of whack. I don't remember exact voltage reading but something like 240 AC and 140 BC.
I assumed it may have been a bad breaker. Luckily we had a spare 3p/20 so we replaced.
Well I took readings again once we re-energized panel at the 3/20 breaker and everything was normal when no load was present. Again they closed the disconnect at humidifier and powered the unit up. Again the same exact issue. We "exercised" the replacement breaker and even intentionally tripped it to see if "something internal" would reset. When turning back on (without any load and disconnect open) we still only got 57 volts on C phase which again tells me this breaker is now bad too.
Obviously these breakers are not cheap and we cant just try another breaker.
Has anyone else had this problem and if so what was your solution? I personally think something in the humidifier is doing this to the breakers. They are not tripping and the 3 pole breaker opposite side is all good with 277/480 readings so I know its not the buss. All other breakers in panel above and below are working normal.
All suggestions welcome.
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