installing wall-mount elbow supply

I'm putting in an elbow supply for a handshower option in a shower installation, and realized I don't quite follow the installation procedure. I have roughed-in a 1/2" male pipe nipple, but the elbow supply itself only goes on after the finish wall is complete. At that time, I will not have access to the wrench flats on the pipe nipple since that is behind the finish wall, so I will be turning the elbow supply onto the nipple without any backup wrench to relieve the torque on the piping inside the wall.

All the other threaded rough-in connections for the shower valve (and a bathtub too) were done with a backup wrench, this seems to be the lone exception.

I did a test and was unable to eliminate leakage with hand-tightening only, so I know I'm going to need a wrench to get one more turn onto the nipple.

Am I missing something, or can I just torque away on the elbow supply and expect the 1/2" copper pipe inside the wall to withstand it? I haven't started the finish wall yet so there is still time to make some modifications if I have something backwards.

Any thoughts appreciated!

P.S. I need a good seal on this connection because the way my main shower valve is arranged, the full 60 psi water pressure remains in the elbow supply (it has its own little stop valve) even when the main shower flow valve is closed.

I'm surprised it is a male fitting...

Normally, you'd have a drop-ear L, and have screwed it to some blocking.

Don't think it's a great idea to have the main mixer valve outlet remain pressurized, if I understand what you said.

Yes, that's correct, this shower assembly contains a pressure/balance valve with a separate flow valve controlling one outlet, and two 'auxiliary' outlets for mixed water that remain pressurized. When I bought it, I hadn't realized that the flow valve only controlled one outlet.

So, the suggested installation for the optional handshower has this elbow supply fitting connected to an 'auxiliary' outlet of mixed pressurized water. At the same time, the elbow supply fitting is female so the rough-in connection for it is male. I didn't see any male drop-ear fittings at home depot, but I guess I should just put in a regular drop-ear with a male-male pipe nipple or something and that assembly should also be strong enough. Sounds like a plan, thanks for the input.

valve

What is the model number for this valve? I cannot visualize HOW, unless you have a valve with two handles, one handle can turn the valve on and off, and also control the temperature, AND still have "mixed" water at those two outlets. In fact I have NEVER seen a valve which could do that. Either the valve controls the volume and temperature at ALL outlets, or it controls only the temperature and individual valves control the volume.

You are right, it does have two separate handles; didn't make that clear I guess, I'm a beginner in this area. So, yes the one handle does the temperature setting for all 3 outlets, and the second handle controls the flow on 1 outlet only. The two remaining outlets are assumed to have their own shut-off valve in whatever fixture is attached to them I suppose. I suspect it is a standard arrangement, though I wouldn't specifically know.

The odd part to me is just getting this elbow supply fitting installed on a pressurized outlet. I can't find much about this scenario in searching around the internet; perhaps it is not so common and most people install a handshower off a tee downstream of the main shower flow valve...?

Great forum by the way... I've roughed in a complete bathroom all the supplies and drains for 4 fixtures, the bathtub is all hooked up now and leak-free with shower sink and toilet still to go. Got lots of good answers along the way just by browsing existing threads.