[jeansidebottom]

Good morning. I have metered my incoming residential service at 248/124V single phase. My branch feeder to a shunt trip breaker is 248/124v single phase. I am using a GE shunt with the Neutral connection at the back of the breaker.
The electrical at the hot tub terminations is 248V A to B, and A to N and B to N. The voltage between ground and N is 124V.
How did this happen?

 

[joed]

The neutral is floating. Did you connect the breaker pigtail to the neutral bus?