Wetroom Electrics Sanity Check Please!

Hello All

I plan to do the following in my new wetroom regarding the electrics and need a sanity check!

I have spurred off the ring main with a 30 AMP junction box which is under wooden floor boards which will remain accessible. This junction box is outside the wetroom.

I have one spur running to a 13AMP switched FCU which is located on the wall outside the wetroom using ring main cable (2.5mm) This will then be wired into a thermostat which will control warmup UFH. The TSTAT is also situated outside of the wetroom above the FCU by approx 1.5 metres. The UFH will pull 1KW.

The other spur will be running to a switched FCU timer which will control my dual energy towel radiator also using ring main cable.

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towel rad will pull 300W. This again is sited outside the wetroom next to the FCU for the UFH. From the timer I plan to run another length of ring main cable to a 20amp flex outlet wall plate. The heating element for the towel rad will be wired to this.

Is it safe to have a flex outlet plate in the wetroom, just a standard one? or can you purchase IP65 rated flex outlet plates. If the standard is OK, how comes, is it becuase you wont actually be attempting to touch it with your mits??

I see the heating element has IP64 stamped on it where it screws into the radiator.

Any help and comments appreciated TIA

Cheers

Richard

PS No mention of Part P please.

Reply to
r.rain
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Forgot to mention the fact that the ring main the spurs are coming from is an upstairs ring main very lightly loaded!!!!

Cheers

Richard

Reply to
r.rain

My personal choice on this would be a separate RCD protected supply to the radial wiring that enters the wet room. It's because of the wet room situation, and the fact you have electric UFH and drying elements in close proximity to your, most likely, bare extremities.

I would supply a stand alone RCD unit with T&E cable of 4 mm csa' from a 15 or 20 Amps MCB in the main consumer unit. I'd then take radial wiring in T&E 2.5 mm csa' from the RCD unit to the appliances as you say above.

I personally feel safer knowing that if a fault does occur, say in some inaccessible point, then the RCD would make sure that the supply is tripped off without putting anyone in danger while being wet in the wet room.

This also separates the new heating circuit you install in the wet room from the rest of the house, and it saves time in having to check which part of the ring circuit is actually causing the fault.

I would also make sure that all metal parts in the wet room are double earth bonded with at least a 4 mm csa' conductor right back to the earth bar on the main consumer unit.

As for the flex outlet plates. Yes it can be used in this type of situation, but make sure you smear some sealant around the joint between it and the wall to stop water droplets from getting in behind it. In an installation such as this, I personally use plain blanking plates with a knock out on one edge. This is so a I can place the knock out pointing downward which then allows the flex to hang so moisture can't run back up it and into the gubbins inside. Finished with some sealant around the gap between wall and plate and it usually lasts for many years without causing problems.

This is all my own personal choice for this type of installation and in no way does it have to be done like this. But for total safety sake I prefer using this method on this type of job.

Now all you have do is wait for the boffins to come along and spout all the regulations and technical details at you. Then you can make a more informed choice of the method you use on this.

Good luck with it.

BTW, csa' = cross sectional area

Reply to
BigWallop

Many flex outlet plates have downward facing flex outlets.

Using your blanking plate, how do you provide a cord grip?

Owain

Reply to
Owain

Theyre not perfect, but they generally will. I'd sooner put towel rail and ufh on the CH myself. You wont need them in summer after all. And run cost will be much lower.

they should normally be equipotential bonded rather than earth bonded. Double bonding would only be needed if your house suffered antisafety vandals. Bear in mind everything is bonded once or twice already anyway, always by CPC and often by copper piping as well. Plus you have mcb and RCD protection.

I'm a bit more hesitant about that. I would use properly rated kit. Any gap at all and youve got hot 100% RH air wandering into a colder pattress, its a recipe for condensation on the electrical connections. You can silicone the wall junction, but theres the cable outlet as well.

NT

Reply to
bigcat

I provide a cord grip with the many flex outlet plates with edge knock outs that already have them. If I have to use a completely blank plate that I have cut a flex outlet point on myself, then I use a cable tie to fix to the back box and secure the flex in place.

But I do prefer to use flex outlet plates that have edge knock outs, rather the ones with the flex outlet in the middle of plate. This is especially so in an area that contains high moisture content in the air.

Reply to
BigWallop

Thanks all. So my plan is OK but not ideal, I didn't see any major objections. The problem I have is that I cannot get to the CU without ripping up loads of floor boards and drilling holes in joists, the radial option too would of been my ideal setup. Now onto the bonding bit, what is it exactly I will need to do? What's equipotential bonding as opposed to double bonding? looking in my other bathroom I dont see any earthing at all on the copper. Do I need to earth my towel rail, or the pipes going to it? I guess if there is an earth somewhere on the copper this will be OK??

Thanks for your help as usual

Cheers

Richard

Reply to
r.rain

Firstly equipotential bonding is not earth bonding. The purpose of it is to ensure that if there is a fault that lifts the CPCs above earth, everything raises equally during fault conditions. Its a backup of debateable merit since everything should already be bonded.

Use either 4mm2 insulated or 6mm2 bare wire, and connect everything metal together, using the proper clamps. Pipes, rads, heaters, any electrical appliances in the room, taps etc

NT

Reply to
bigcat

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