I am doing a 40 amp 2 pole gfci breaker install for a hot tub that needs only 240v. The gfci breaker has 2 neutral terminals which I understand, but in this install there is no neutral needed. Will the gfci monitor an imbalance b/w the 2 hots?

If the tub manufacturer states a grounded conductor(neutral) is not required, connect the line side white wire on the breaker to the neutral bus and leave the load side neutral terminal empty. The breaker will work as designed.

steve