• Welcome to PlumbersForums.net - The international free plumbing advice forum. Professional plumbers sharing advice with fellow plumbers and DIY alike. Register for free today! - Checkout the Plumbing Advice forum and then our Plumbing Videos area which still needs populating.

From the United States of America? - Checkout our specific plumbing forum for you:USA Plumbing Forum

Discuss REPLACEMENT SHOWER HEAD ARM ADVICE: WILL IT SUPPORT A 300MM SQUARE HEAD in the Bathrooms, Showers and Wetrooms area at PlumbersForums.net

Hello Everyone

I am replacing an all in one shower arm and 200mm square showerhead a head has fallen off and I had to remove arm.

I want to replace with a 300mm head like this.

I have now been reading online that a 300mm head might be to heavy for the shower arm and it may cause problems later on.

Please can anyone advise if if it will be ok to fit a 300mm showerhead and arm or should I just get the smaller 200mm head as its lighter.

Any recommendations for a specific shower head and arm would be much appreciated. Is it worth paying a bit more?

I have attached some pics of broken head and arm

Thanks for your help in advance



  • image2.jpeg
    24 KB · Views: 7
  • image1.jpeg
    39.9 KB · Views: 6
  • image0 (4).jpeg
    image0 (4).jpeg
    32.3 KB · Views: 6
Probably more to the point have you sufficiently flow/volume from your shower mixer to make the bigger head usable?
May be easy to change the arm probably 1/2in male thread but will depend on how well fixed (or not) the connector behind the tiles is.
Last edited:
Thank you for your quick response. I have taken the arm off carefully and you can see the pictures below where it was connected to the wall. The house is supplied by a megflow and combi boiler system in the loft
Will this be enough pressure to supply the 300mm head ? Will the 3000mm head be safe on arm?

Thanks Again for your help


  • image2 (1).jpeg
    image2 (1).jpeg
    77.9 KB · Views: 4
  • image0 (5).jpeg
    image0 (5).jpeg
    24.6 KB · Views: 4
  • image1 (1).jpeg
    image1 (1).jpeg
    29.2 KB · Views: 4
That head gives a max of 12ltrs a min output. Maybe temporarily put old arm in run shower into a bucket for 30 seconds if you have 6lts or more your in business.
As for the arm standing weigh that really depends on how well fixed the connector in the wall is.
Thanks Again You have been really helpful

Would you advise to spend a bit more on the head and arm o does it make much difference.

Thank you
We use Bristan stuff mainly probably way more than you want to pay!
As you have found ot easy enough to change if it looks shabby in a year or two
Hello Everyone

Sorry to bother you again
I bought the Bristan arm and head as the local plumbers merchant recommended it as well. The
shop said I could just screw it in sane as the old one. However it has come with a back nut and lock nut as well which the old arm did not have.

I just wanted to check are these nuts necessary?
The instructors also state that compound is required. Once again is that necessary and where should I add it.

Finally I have noticed the thread going into the wall on the new shower arm is longer that the old arm. Will I need to cut this down?i have added a picture of the new and old arm.

I have attached some pictures.

Thanks again in advance


  • DE6298AF-125A-4C9C-BC44-D4596EB2DB34.jpeg
    157.1 KB · Views: 2
  • A3E7446F-5056-404C-9293-B7D7B022A893.jpeg
    391.4 KB · Views: 2
  • 5FD1C317-20AB-4B78-B280-9D16413EA136.jpeg
    331.6 KB · Views: 1
  • 1FD0EEF7-4499-4F33-917B-293C99D622D9.jpeg
    24.6 KB · Views: 1
Your old arm has a bezel/cover plate to hide the hole in the wall.
Does your new arm have similar? If so I guess the back-nut with two flats is to hold that on.
I don't think you need the other one in your situation.

Looks like you'll need to shorten the thread, but the old one looks too short. Better to do some careful measuring and try to leave the maximum thread that will let you get the cover plate flush to the wall.


The backnut is for use if you have access to the reverse side, or open studwork or some such - you can’t use it in your situation.
You will need either ptfe tape. or loctite 55 cord or loctite 577 sealing compound on the threads of your shower arm - which will also need shortening.
Hello Ben

Thank you for your advice. I got it fitted and working yesterday. I will need to take it off and cut it down as you all have suggested. Biut I had to get it working yesterday or their would have been a family revolt... Should I cut it with a hack saw or pipe cutter?
Thanks to everyone who has responded

Reply to REPLACEMENT SHOWER HEAD ARM ADVICE: WILL IT SUPPORT A 300MM SQUARE HEAD in the Bathrooms, Showers and Wetrooms area at PlumbersForums.net

New Posts Threads Members