Underfloor heating in bathroom and Part P.

[eveares]

It seems strange to me that a room containing a bath or shower is a special location, but outside is not.

And does underfloor heating in a bathroom fall under part p, I guess it does even though it is under the floor.

What is the best way of going about installing underfloor heating yourself, bearing in mind it will be tiled over once the 2nd set of measurements are done and pass within the allowed limits?

Is it possible to install and wire it up your self and then provide all the readings to an electrician (Insulation Resistance and Normal Resistance measurements) who would check it and then sign it off OR would this be the typical case where an electrician would not deal with someone else's work.

If not what should one do and how much should one pay for an electrician.

 

[EFLImpudence]

It seems strange to me that a room containing a bath or shower is a special location, but outside is not.

If you mean outdoors then a good point.
I presume it just no longer comes under the same Building Regulation regarding notification but there are similar electrical regulations.

And does underfloor heating in a bathroom fall under part p, I guess it does even though it is under the floor.

It does specifically say above the finished floor level so ...

You will know it is not exactly a brilliant system.

What is the best way of going about installing underfloor heating yourself, bearing in mind it will be tiled over once the 2nd set of measurements are done and pass within the allowed limits?

Wet - so notification irrelevant.

Is it possible to install and wire it up your self and then provide all the readings to an electrician (Insulation Resistance and Normal Resistance measurements) who would check it and then sign it off OR would this be the typical case where an electrician would not deal with someone else's work.

No.

If not what should one do

Get him to agree to do it as you progress.

and how much should one pay for an electrician.

Whatever you agree beforehand.
You are allowed to give him more than that.

 

[eveares]

Get him to agree to do it as you progress.

Thing is I am doing it for my mum (our house) and doubt she will want an electrician in multiple times what will likley cost hundreds.

After all, is it any point of getting an electrician in once it is tiled. I guess it the fact that an electrician needs to lay the wire and wire it up and not just verify the IR and conductor resistance is within limits once installed, if so it seems a bit over the top for someone who is competent in skill but not legally qualified.

I have all ready done the first set of measurements with the coil still in the box and all is ok, although I suppose again an electrician will not trust someone else's readings such as mine.

Again, is this work that i propose notifiable as it will be below the finished floor level?[/quote]

 

[Taylortwocities]

Mate, its your Mother, so it doesnt really matter if you put electricity under her bathroom floor and it goes faulty. Hey, maybe you're going to benefit from the will???

But seriously….

Don't mess around with anywhere where electricity and water and people come together. It's not worth the extra £100 or so. Get someone who knows what they are doing, with the proper test equipment to make sure it's all OK. If you want to save a few quid, most electricians will work with you and do the PROPER snd CALIBRATED and CERTIFICATED tests before, during and after the grunty tiling works.

 

[eveares]

Don't mess around with anywhere where electricity and water and people come together

I don't ever mess around with electricity, I know it's danger and respect it for that.

Get someone who knows what they are doing

I am sure your not, but still I hope you're not suggesting I don't know what I am doing. I may not be *technically* qualified, but electrics are not new to me at all and I have confidence in what i do.

proper test equipment

Not only have I measured the DC resistance with my multimeter giving me an acceptable reading of 133.9 ohms for a 400w heating coil, but I have also measured between the conductors and the earth braid using IR meter at 500v DC and got a value of =>2000 Mega ohms.

(And yes I have tested my IR meter against the 10 Mega ohm input impedance of my multimeter and get exacly 10.00 mega ohms on my IR meter.)


Will speak to my mum later though.

 

[ericmark]

I did it for my mum so speaking from experience.

It would seem as being done because of her disability there was no charge for registering the work. I live in Wales which does mean Part P is slightly different to England. I was also doing other work so LABC would be involved.

It was to have been done by a builder who ran off. The tile cement was faulty and not drying so the tiles moved damaging the underfloor heating so had to ripe the whole lot out and start again.

Problem one was finding out if the heating was in fact suitable for a wet room. There has to be either a earthed braid around the heating wires or a earthed mat has to be laid on top of the heating wires and it took some time to contact manufacturer to be sure it was OK.

With new good quality adhesive special stuff designed for underfloor heating to allow for expansion we did lay the tiles including a pocket for the sensor. Under floor heating has two sensors one ensures floor not to hot to walk on other controls room temperature both use the same thermostat.

Lucky we also installed a towel rail as when tried with the fan required by building control the wet room simply was too cold without the heat from the towel rail although if the floor had been any hotter we could not have walked on the floor.

We used sculptured tiles for better grip in hind sight a mistake as they held the water so took longer to dry a black smooth tile is the best black radiates more heat and smooth dries quicker.

Although as hot as toast going into the shower the water clearly cooled them down it took 1/2 to re-heat by that time mother no longer in the shower room.

After 6 months the thermostat failed and it was found the sensor in the pocket had also gone. However it jammed so could not be renewed. Still it worked reasonably the same without the under floor sensor. However when the second thermostat failed we gave up.

To put it mildly it was a white elephant and in real terms useless. In order to fit the underfloor heating we also changed the consumer unit as needed RCD protection. This was done by builders electrician but he had problems and left it without the RCD which was really the only reason for changing it as he could not stop it tripping.

The LABC wanted me to pay for some one to inspect and test and I objected. They would not allow my son to do it as he only had a C&G 2391 and 2381 (as it was then) they did allow me to inspect and test as I had a degree however my degree did not really show I was qualified seems the LABC inspector had no idea what a C&G 2391 was.

Once I submitted the installation certificate the building inspector issued the completion certificate without visiting the property.

I would now not dream of fitting electric underfloor heating. My son has fitted water underfloor heating but really only as a heat sink to get rid of excess heat from solid fuel cooker.

Of course testing was important and we did have a full test set which cost my son around £750 without that we could not have done it.

In hind sight it was a complete waist of money. With a simple bathroom likely it would work better but not enough to heat room you will need another form of heating as well.

Do check dates on the glue as it seems not that much is sold so suppliers often have glue about to go out of date and if kept in wrong temperature it can go off anyway. Also test a sample of the glue in case it has been stored at wrong temperature. Remember has to be a small gap on each tile to allow for heating up standard spacers as used with wall tiles are no good spacers must not be left in.

Learn from my mistake do not put too sharp a bend on the sensor pocket. May be worth fitting a spare pocket.

I don't really know why we bothered my mother only has one leg so sits in a special wheel chair in the shower so does not put her feet on the floor anyway!

 

[eveares]

Seems like there is no way around without either having an electrician or the LABC come and test it at each stage. am I correct?

Is there any point of filling the following form out myself other than for my own reference?

Form: http://www.tlc-direct.co.uk/Technical/DataSheets/BushNelson/EHC.pdf

 

[ban-all-sheds]

And does underfloor heating in a bathroom fall under part p

Yes.

 

[ericmark]

Do remember coming under Part P and requiring registering are two different things. It seems daft but since below floor level it will only require registering if it forms a new circuit.

You are allowed up to 2kW on a ring final as permanent load and 1 sq foot needs around 10W to get nice and warm but not too hot to walk on and considering you will not lay it under the bath or loo then likely less than 2kW so could be fed from the ring final.

However as others have said it's not what is allowed but what is safe. Laid on a wooden floor your as much worried about damage to floor as damage to person direct and there are chemical heating elements where the mat becomes self regulating as the chemical heats up the resistance increases so placing a laundry basket on the floor will not cause over heating. However these are in the main not suitable for direct use in a bathroom and require an earth mesh above them.

The advantage of the dry system is it's so thin but the wet system is far better at control as water temperature is the maximum temperature and you get no hot spots. As you start adding earth mats the advantage of dry system starts to evaporate.

My landing has central heating pipes under it a good 50mm plus from surface and only two pipes feed and return but landing is always nice and warm to walk on as is the floor of my office also with central heating pipes under it.

My son when he moved into his own house used plastic central heating pipes and fastened them to under side of floor boards when the ceiling was down snaking across the floor either side of where he intends putting the bed and it works well. It removes chill off the floor rather than heat it.

I can't see the hypocaust warming the home on it's own. Although we can see examples

it's not a complete house so can't see if any other form of heating also used. The floor is rather thick and one would think it stored a lot of heat in the floor its self.

There are today storage heaters

the rocket mass heater shown is a good example takes a long time to heat up and a long time to cool down talking about week to cool down.

Underfloor heating is not that bad takes around 1/2 hour to hour to heat up and only once heated will it start heating room and so needs to be on around 2 hours before you use the room. The one we saw was in a guest house with around 10 people using the bathroom so underfloor heating was left on 24/7 and was not under shower only where one would step out of the shower. It worked very well hence why we wanted to copy for my mother. But for one person using the bathroom in bare feet once a day it just did not work.

Living room where running 24/7 may be. Bathroom you just don't spend enough time in it.

 

[eveares]

However as others have said it's not what is allowed but what is safe

Being that it will be below the finished floor level and does not form a new circuit and thus does not require notification, I will do it myself.

Oh, and it's not the primary source of heating in the room, the radiator is.

Thanks everyone.

 

[TheCliffords]

Good on you sir, not one electrican can really support part P it's a glorified tax and we all know it! (If a plumber (boiler wireing) or window fitter (solar PV)can get a small part of Part P it's a joke)
If you feel confident doing the work then you can do it in your OWN home, if you are spuring off the ring and have worked out the full load correctly and have fused and switched it correctly, installed the right cable and it's RCD protected you are covering all the points, if a sparky charges you more than £20 to £30 an Hour to check your work he's over doing it.

 

[JohnW2]

If you feel confident doing the work then you can do it in your OWN home, ...

It is not relevant whose home it is. Anyone who is competent to undertake the work (design, construction and testing) can undertake any electrical work in anyone's house, whether 'for reward' or not, provided only that the work is undertaken competently and safely (i.e. in compliance with the law, aka 'Part P' of the Building Regs) and that any notifiable work (of which there does not appear to be any in this case) is notified.

Kind Regards, John

 

[eveares]

If you feel confident

Of course I do, otherwise I would not do it. I have done many electrical related work in the past such as running SWA up to my shed, putting in drive way lights, adding a 2 way light switch in my living room, adding a porch light, etc...

if you are souring off the ring

I have no Ring Final Circuits in my house, it's a 20 Amp radial circuit that provides two bedrooms upstairs.

have fused and switched it correctly

Of course I have it provided by a switched FCU with a 3 amp fuse in it fed from the adjacent socket with 2.5mm T&E ... Who would not put a switched FCU in when spurring from a socket!?

and it's RCD protected

Of Course it is! Even if my electrics were not to the latest revision of the 17th edition of BS7671, I would fit an 30ma RCD protected fused spur anyway followed by a 20 amp DP switch.

 

[eveares]

Just one more query, and regarding the 10 year grantee for the underfloor heating.

The instructions state the following.

This guarantee is validated by the Installation Record Form, which
is supplied with every underfloor heating product, being fully completed by the qualified installing contractor at the time of installation and returned to BN Thermic Ltd within 30 days of installation

By qualified installing contractor, I assume it means a qualified electrician.

Also what does the grantee cover, just the product or the cost involved of getting all the tiles up and replacing them as well?

 

[Taylortwocities]

I do not want to be unkind, but

Do you not read the documentation that comes with the product?

Here's the link to the heat mat. http://www.tlc-direct.co.uk/Technical/DataSheets/BN_Thermic/BNM_Series_Instructions.pdf

Two things are very clear.

Page ONE, paragraph ONE it states

1. Personnel.
The M Series Mats should be installed by a suitably qualified, professional builder and/or electrician. M Series Mats are not a ‘do it yourself’ product. It is most important that the installer completes the Installation Record Form that is part of this booklet.

The last page of the installation instruction state exactly what the warranty provides.. Again, I quote:

The guarantee covers the full purchase price but not the cost of repairing or replacing the heater in the floor. Control devices carry the manufacturers 1 year warranty only.

So, if it goes wrong you don't have a leg (or a heated floor) to stand on.