bathroom circuits

[the doctor]

hi all,

I have been took on to do minor works and circuits in bathrooms. The regs tell me that all circuits must be 30mA protected in the bathroom area. So far so good. I also teach and quote this reg so that is ok as well.

Now i have to do these works i really started to think about things and wondered why i would have to rcd a circuit supplying 12v downlights. What i am trying to say is that an rcd would provide no protection at all.

Following on, i made some calls to elder statesmen of the regs and have found out that the reg is a mistake. It should say "circuits supplying class I and II circuits in the location.

The dilemma is do you comply with the reg for downlights or disregard it till they get round to ammending it. Finally if i take the latter action do i book it as a departure or simply not mention it on the certificate?

Interesting eh?

Best wishes

alan...

 

[green-hornet]

Very good point, however I have just installed a RCD for the lighting circuit to the bathroom.

My reason for this even though the lights used are 12v you never know if they would be changed at a later date.If they get fed up with changing the trannies they could convert the lights to mains.

 

[M107]

AS GH says it's that old what if the elv fittings are done away with at a later date?

You can only go by what is in the book at this moment in time (every circuit on rcd).

Thats my take on it.

Hows the next book going Doc?

 

[a1]

Stick to the current regs Doc. (but you knew that though. )

(Did you ask them for it in writing whle you were on the phone, Doc?)

 

[a1]

AS GH says it's that old what if the elv fittings are done away with at a later date?You can only go by what is in the book at this moment in time (every circuit on rcd).

Thats my take on it.

Hows the next book going Doc?

But there again M, You aren't psychic, you can only provide for what is there at the time of the install. It passed then.

Yes, I know - make acceptances for any future uses etc.

 

[the doctor]

thanks for the replies...

well, the two men i spoke to are both MIET members and they say that even though the IET know it is a mistake I still have to rcd protect supplies to 12V down light circuits that are not in the bathroom just because the 12v end is in the room.

i like being a maverick and will do the job, if it comes off, to suit myself Pray

ah..the book! well it is done and is being proof read as i type. i look forward to printing at the beginning of next month....then i shall carry on with other projects that i have had knocking around inside my head for a while now..B-)

 

[M107]

ah..the book! well it is done and is being proof read as i type. i look forward to printing at the beginning of next month. B-)

Look forward to it.

 

[Andy™]

It should say "circuits supplying class I and II circuits in the location.The dilemma is do you comply with the reg for downlights or disregard it till they get round to ammending it. Finally if i take the latter action do i book it as a departure or simply not mention it on the certificate?

Interesting eh?

Best wishes

alan...

isnt 12V Class III? so even if it says you must RCD class I and II, you still dont need to for 12V.

i would still RCD it, after all, RCD's are now the answer to everything!

 

[spinlondon]

You don't have to comply with the current Regs., as long as your reason for the departure is valid.

In this case, you could omit the RCD, and then state the reasons for the ommission as you have posted.

However please be aware, that although a couple of members of the IET have informed you that they believe the requirement to be a mistake, there is no guaratee that the Regs. will be changed.

There are many more members of the IET than those who sit on the panel determining the Regs. Further, since the change from IEE to IET, there are a number of members whose main discipline is mechanical rather than electrical.

 

[delta1]

Newbie Alert!

I would put an RCD on the circuit, as chances are that the cables supplying the 12V downlights are concealed in a wall <50mm, and the dangers of penetration of the 230v cable still exist

 

[Mark2spark]

I know that i'm being an argumentative ol sort, but i have a great deal of problem with this aspect of the regs.

For a start, the wiring for the bathroom lights IS NOT IN THE BATHROOM and is therefore no more dangerous than the light in the next door bedroom.

Secondly a down light is also NOT IN A BATHROOM. Even if you argue that that skinny lip of the flush fitting is in fact in the bathroom, surely it's outside of any zone?

Sorry, just fancied a grizzle

 

[green-hornet]

I think you may be confusing the area, let me explain.

If you was to place any wire in a living room, the cable would be run probably in the bedroom for the lights, apart from the light switch which could be placed outside the room, so even that cable will be outside the living room.

Now lets take the simple task of changing a light bulb(no I am not a gardener).

You try to remove the lighting element but it breaks, no problem, long nose pliers come in usefull to grab the metal element and twist it out of the housing.

Problem is the light blew with the power on and the light is still live.

You make a cross connection with the pliers and "bang" the fuse blows.

All this is fine because your in your living room and the risk of shock is limited.

Now move to the bathroom! Your in the shower same example your body is wet, your naked(god help us) risk of a shock is greatly increased, I would not like to poke about in a light fitting under these conditions.

That is why when the risks are greater we have zones.

You WILL have live cables entering a bathroom, if installed correctly they will be placed behind barriers, which increases your safety.

 

[the doctor]

hi green hornet,

my point is being lost in the posts.

but to reply to you, the regs say all circuits in the bath location are to be rcd protected

to run through your scenario of the broke bulb/live filament i would receive a shock of 12v, also the rcd cannot trip as i am touching a circuit that is electrically separated from earth so i am still not convinced and would still departure it i feel

best wishes

alan

 

[Apache]

hi green hornet,my point is being lost in the posts.

but to reply to you, the regs say all circuits in the bath location are to be rcd protected

to run through your scenario of the broke bulb/live filament i would receive a shock of 12v, also the rcd cannot trip as i am touching a circuit that is electrically separated from earth so i am still not convinced and would still departure it i feel

best wishes

alan

you don't need any current down the earth for the rcd to trip. GH's example is a L-N short. Nothing down the live.

 

[Andy™]

hi green hornet,my point is being lost in the posts.

but to reply to you, the regs say all circuits in the bath location are to be rcd protected

to run through your scenario of the broke bulb/live filament i would receive a shock of 12v, also the rcd cannot trip as i am touching a circuit that is electrically separated from earth so i am still not convinced and would still departure it i feel

best wishes

alan

doubt you would feel a shock at 12V

 

[msb2003]

you don't need any current down the earth for the rcd to trip. GH's example is a L-N short. Nothing down the live.

Maybe I'm missing the point but a L-N short circuit will not cause the RCD to operate as you need an imbalance of sufficient magnitute between phase and neutral to operate the RCD.

The fact they are fed via a SELV source will break the fault path should there be a fault to earth

 

[green-hornet]

My point was not to show fault with or against the argument of 12v, just to highlight that because you can not see a cable it does not mean it is not there ie in the bathroom.

Yes Doctor I agree with the selv being earth free, so would in common sense terms not require rcd protection.

This is one area that will get addressed in the next amendment I would think.

However seldom is a lighting circuit taken to a bathroom seperately so in one form or another will be RCD protected along its length.

 

[jl-heating]

on the subject of bathrooms i have a question on supplementary bonding were would you bond in this bathroom so it does not look unsightly . ???

 

[jl-heating]

Newbie Alert!I would put an RCD on the circuit, as chances are that the cables supplying the 12V downlights are concealed in a wall <50mm, and the dangers of penetration of the 230v cable still exist

i agree totally.

 

[the doctor]

Originally Posted by delta1

Newbie Alert!

I would put an RCD on the circuit, as chances are that the cables supplying the 12V downlights are concealed in a wall <50mm, and the dangers of penetration of the 230v cable still exist

i agree totally.

so then, lets say the circuit to the bathroom was surface wired then?

as i have stated a 12 v bulb in a bathroom gets nothing from an rcd.

i am not saying the rcd is bad, but an unnecessary cost on a bath minor works project..so do you install one to "comply" or ignore it because you know better?

(i am sorry for the scruffy post, but i havnt mastered the quoting bit.... :_| )