I have a 220V cable coming to hot tub. 2 black wires a bare wire. Does it matter which black wire goes where. I know the bare wire would be ground, but I question 2 black wires. I thought 1 would be black and the other red.

That is weird, two blacks. What kind of cable is this?

Oh wait, is this a gray plastic covered cable with two insulated aluminum wires and 1 bare stranded aluminum wire?

If so, this is called SEU cable, look closely at both blacks, one should have a red line or tracer, sometimes hard to see, running the length of one wire.

Testing across both wires, if already connected to a 2 pole breaker will read 240 volts. Or if not then connect both to a 2 pole breaker that is sized for the tub.

Need to be sure what size wire this is and need to know what load is the tub to see if this cable is sufficient.

Also check the tub wiring, most that I know of need 4 wires, two hots, one insulated neutral, and one bare or insulated ground.

It is copper wire. This was already conneted but was disconnected to move the tub for remodeling. The person who disconnected electric is no longer in area and the lady ask me to help her rewire it. That's what is confusing to me, only 2 black wires and a bare one.

OK then it sounds like the older copper SEU cable which is fine, and better.

The blacks are the hots,and does not matter which is which, as long as you can tell where the hots and neutral connect at the tub.