Connecting 15mm copper pipe to shower arm

30 Apr 2015
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United Kingdom

I hope someone might be able to help. I am currently upgrading my mixer shower and want to join my new shower arm (for the shower head) to the existing 15mm copper pipe which is usually concealed behind the wall. (At present the tiles and boards are down so there is no problem with access). The hole of the shower arm measures 15mm in diameter but I cannot for the life of me get the copper pipe to fit into it to tighten it up with a compression fitting. Does anyone know what kind of fitting would sort this out? Do I need some kind of reducer fitting that allows for the 15mm pipe to fit in one end and has a 14mm pipe on the other end?

Thanks very much for any advice.

S. Thomas
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Hi leakydave, thanks very much for your reply. I've uploaded a picture of the shower arm and annotated it (hopefully it makes sense). I'm at work right now so that's the best I can come up with but can take photos of the exact pipe etc once I get home if it isn't very clear. Basically, the 15mm copper pipe won't fit into the threaded end of the chrome shower arm so I presume I must need a special fitting, but just haven't a clue what it is called! Thanks again! Regards, S. Thomas


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Depends on how that mounts to the wall, either would do and there are other parts that would fit, but basically you need a part with 15mm compression at the pipe end and half-inch BSP at the shower end.
Thanks very much Picasso and OwainDIYer - much appreciated.

Picasso - the link you gave doesn't see to be working (might be my computer however). It says 'page not found'. I'm dying to know what the part is you wanted to show me!

OwainDIYer - I take it it doesn't matter if the 1/2 BSP at the shower end is narrower than the shower arm hole and doesn't fit in snug?

Quick final question - the shower arm is made of chrome-plated brass and feels a lot more delicate than the copper pipe. Should I use a plastic fitting to connect the copper pipe to the shower arm or will a metal fitting be fine?

Thanks again!

Thanks denso13 - is there a straight version of that fitting? I've drawn a (slightly dodgy) picture of the shower setup as I'm unable to take photo at present. The pipe has been bent towards the shower cubicle wall so would need a straight fitting to attach to the shower arm. Thanks again.


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The seal at the threaded connector is made by a washer pressed between the end of the connector and the seat inside the shower fitting. It's not a copmpression fitting that seals around the pipe.
I think nearly shower arm I have seen has been fixed by a wall plate elbow, (the thing denso13 posted) the copper tube goes in the compression fitting and its then screwed to the wall, this gives the shower arm stability, the arm thread is wound with ptfe tape and screwed in to the wall plate elbow.
Hello everyone - I just wanted to say a massive thanks for your excellent advice. I managed to find a female coupler that has done the job. Shower is working and does not appear to be leaking. Chuffed to bits with this achievement :)

Thanks again!

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