wiring for electric showers again

[multimapper]

Hello

I am fitting an electric shower onto a stud wall, with suitable reinforcement. An electrician will make the final connection and certify it.

I expected the shower (Mira Go) to be sealed against the wall, but this you must not do - the shower is designed to have space at the rear for ventilation. I want the electrics and plumbing to come into the rear entry, obviously through a hole in the wall.

My question is, given that water can trickle down the gap at the back of the shower, then onto the pipe and cable, what should I do a) about protecting the pipe and cable from the edges of the tiles and b) sealing them. I can see that making a hole which is only slightly larger than required and putting sealing compound around is possible, and should be okay since there is not going to be any movement, but I am aware that elsewhere cable entering a metal box has to be protected by grommets even though there again there is no movement. One solution to this would be to feed them through hosepipes, but this seems a little DIY/Heath Robinson.

I can't find any information concerning this in the installation instructions that came with the shower, nor can I find it mentioned anywhere on the web including here. Yet it is something that many installers will face?

John

 

[ban-all-sheds]

An electrician will make the final connection and certify it.

Have you found an electrician prepared to do this?

The law says that if he certifies it for Building Regulations purposes he has to do it all - deciding on cable size, MCB rating, cable routing etc, doing the installation of the cable, including getting it through the wall and into the shower in such a way that it won't be subject to damaging external influences such as water & chafing.

It may be possible for you to do some of the donkey-work, but only under your electrician's strict guidance and supervision, so you have to find an electrician prepared to let you do the work and ask him all of these questions.

Simply doing everything yourself, even with advice from here, and presenting an electrician with a fait accompli to connect & certify won't work.



//www.diynot.com/wiki/electrics:part-p

 

[multimapper]

An electrician will make the final connection and certify it.

Have you found an electrician prepared to do this?

The law says that if he certifies it for Building Regulations purposes he has to do it all - deciding on cable size, MCB rating, cable routing etc, doing the installation of the cable, including getting it through the wall and into the shower in such a way that it won't be subject to damaging external influences such as water & chafing.

It may be possible for you to do some of the donkey-work, but only under your electrician's strict guidance and supervision, so you have to find an electrician prepared to let you do the work and ask him all of these questions.

//www.diynot.com/wiki/electrics:part-p

Thanks

Have found more than one in fact. Have discussed most of the issues you have cited, just not the aspect I mentioned. May be it makes a difference that as an MIEE I am "a competent person" although I am only too aware of my limitations. I can't ask my chosen person because he is on holiday.

I certainly wouldn't present an electrician with a fait accompli - that would seem to be like a prelude to 'open your wallet and ...'

Still would like an answer though.

J

 

[333rocky333]

Instead of a grommet could some sort of gland be used that would extend more into the stud wall.

 

[ColJack]

could you do us a picture of the shower with the front off?

 

[multimapper]

Thank you both for your interest.

I think that this will do it

The service funnel has been taken off exposing the water inlet and the electrical connection block. The cable can come in on the surface from the top (ie left of picture) or bottom, or through a hole in the wall.

The unit does not sit flush with the wall, there is a gap behind to help ventilate it.

Thanks again

John

 

[spark1]

John. you state " An electrician will make the final connection and certify it". What exactly do you mean by CERTIFY. If you mean He will Inspect & Test it, then he will be able to issue a Periodic Inspection Report Only.What do you intend to do to satisfy Building Regulations Approval ?
.If you mean he is going to issue an Electrical Installation certificate this is not permitted and is in contravention of the building Regs and the Self-Certification Scheme Rules.Only the person or company carrying out the work can issue an EIC.
Have you informed Building Control of this work..Or alternatively Is your
nominated Electrician a member of a Self Certification scheme [Part P Spark]
It would not be approprite to give guidance on your question without knowing these answers. Have you not raised this with your Electrician .

 

[multimapper]

Hi Spark1

Thank you for your concern. I didn't think it would be necessary to go into the detail I will now provide for the answer to a simple question.

Originally I was going to tile the wall and have water and electricity supplies surface mounted. I was going to do all the work including preparing the agreed cable route and leave Sparks to lay the cable and make the electrical connections. Sparks agreed to this and has now gone on holiday, prepared to do his bit when he returns, including a new consumer unit.

Meanwhile I have been investigating whether I can run the pipe and cable through the wall cavity. This would give a neater finish. Even before this, when reading the shower's installation instructions, I had wondered how a rear entry would be made waterproof.

Hence my question, to which there must be an answer that can be divulged to an ignoramus?

Thank you for your concerns

John

 

[kai]

I think that this shower MUST NOT have a rear cable entry, as the OP stated, there is no effective eay to seal such an entry - you should have bought a Creda Aquawave or similar model - Argos or B&Q etc, which does allow rear entry (like mine), and can be sealed around the edges once installed (like mine) reducing the risk of water leakage. (Ventilation is achieved through a special shielded ventilation slot at the bottom of the shower box unit.)

 

[multimapper]

Thank you

I think you have hit the nail on the head! I'll use surface mounting, or possibly take it back.

Thanks for resolving the issue. Mind you, I'd still like to know what you did about the cable coming out of the wall in yours. Presumably the wall is tiled behind your unit.

Which? has some advice on selecting and installing showers. They give the advice that some showers are easier to fit, or have more ways to be fitted, than others so to choose carefully. However, after having looked at several showers, I couldn't find this information. Seems like you have to buy one to find out.

J

 

[kai]

The 10sq.mm. cable for the shower was routed to the bottom right of the shower box, and sealed round with the Solvent Free Evo-Stik Nail and Seal, before fitting the box, Once the box was fitted over the tiling, the edges were carefully sealed all the way round, taking great care to avoid blocking the special ventilation slot at the bottom.

Make sure the edges of the box and tiling are absolutely clean, before forcing the sealant firmly into the gap all the way round the box.

Allow to cure fully for 24hours before using the shower.

 

[skenk]

I think that this shower MUST NOT have a rear cable entry, as the OP stated, there is no effective eay to seal such an entry - you should have bought a Creda Aquawave or similar model - Argos or B&Q etc, which does allow rear entry (like mine).....

Rubbish. Mira make some of the best electric shower around and it's no problem having rear entry. You are not supposed to seal around the shower unit (although I have seen it many many times with no apparent problems). This does not stop you from sealing the hole where the pipe and cable come through the wall, i would suggest with silicone. I would say that no extra reinforcement is required in a stud wall as long as it has been put up properly and with 400mm centres although you really want water resistant plasterboard or aquapanel rather than standard drywall as water can seep through the grout and rot the wall especially if the shower is used a lot (grout is not waterproof unless it's special swimming pool grout).

Creda showers I have never heard of and if your picture is anything to go by they're ugly as sin. The Mira sport in my old flat was old when I moved in in 2000 and was still going strong (albeit with a new heater tank a few years ago) a month ago when I left. There was 3-4 people living in the flat the entire time. I wouldn't buy anything else except Triton when you need the cable and pipe entry on the other side.

 

[nozspark]

Yep,,

seal the hole in the wall with silicone and then just surface mount the shower as per instructions..

As for Creda showers being good,,,,, I have installed one in the past and they are one of the cheapest, nastiest showers on the market,,, the covers are really difficult to fit!!

I would rather recommend a Gainsbrough!!

 

[multimapper]

I would rather recommend a Gainsbrough!!

is that damning with faint praise or are you saying that you strongly recommend them?

 

[nozspark]

I had a Gainsbrough for about 10 years in my old house... it's possibly still there now!!

I would never recommend one though

I always recommend Mira!