I have a box on my house for a A/C which I believe it is 50 amp. The A/C box has 2 black and a ground lug. I want to hook a hot tub to that box but it has 4 connection, 2 blue, white, ground lug. How do I hook this up. Does the white wire on the hot tub go to the ground on the A/C box or do I have to run a line from the circuit breaker box. Thanks for your help.

