light fitting in bathroom

[securespark]

Two quick points:

Keen: why is changing the cable going to be impossible?

If it's a pullcord, all you have to do is run a new cable in from there to the lighting point. There's no chasing in the walls...

And second,

and metal fittings shouldnt be used n a bathroom anyway

Why??

 

[keenbutconfused]

The cable from the light to the switch runs up into the ceiling and emerges at the switch about a metre away.

The room is an extension and I do not have access to the void above the ceiling and do not know how I would go about threading the cable through. Am I being an idiot, and is there an easier way.

In addition, am now worried about the earthing of the taps and bath in the shower room. If the electricity enters the room through the pull cord switch and the earth there is not connected to anything then can't see how earthing back to the consumer unit works.

Is there an easy way for me to test earthing?

 

[andy]

And second,

and metal fittings shouldnt be used n a bathroom anyway

Why??

was told at work last year that bathroom fittings should be class 2 and were not allowed to install class 1.

 

[andy]

In addition, am now worried about the earthing of the taps and bath in the shower room. If the electricity enters the room through the pull cord switch and the earth there is not connected to anything then can't see how earthing back to the consumer unit works.

Is there an easy way for me to test earthing?

to test the earth at the light use a multimeter. if earth isnt connected, there should be no voltage

to test earthing of pipes, use a multimeter with a long lead. connect 1 end to the MET

 

[keenbutconfused]

Thanks Andrew

Can you confirm the wiring from the diagram I have drawn.



What is the MET? At the light, do you mean attaching the live wire to the multimeter and then the other end to the earth?

 

[ban-all-sheds]

was told at work last year that bathroom fittings should be class 2 and were not allowed to install class 1.

Firstly, I don't believe that's true.

Secondly, metal does not mean Class I.

 

[ban-all-sheds]

What is the MET?

Main Earth Terminal - it's at the CU, and it's where the earth cables from the CU and the incoming supply meet, also (hopefully ) the main bonding cables from the incoming water/gas/oil/beer pipes.

At the light, do you mean attaching the live wire to the multimeter and then the other end to the earth?

Yup - with the meter set to an AC volts range >250, measure the voltage between Live & Earth. Best to use the multimeter probes on the terminals of the switch rather than actually attaching the cables to the multimeter. Obviously take care doing this.

For the other test, set the meter to the lowest resistance range it has, and check for a low-resistance path from the pipes to the MET.

 

[andy]

Thanks Andrew

Can you confirm the wiring from the diagram I have drawn.

that is correct.

 

[andy]

was told at work last year that bathroom fittings should be class 2 and were not allowed to install class 1.

Firstly, I don't believe that's true.

Secondly, metal does not mean Class I.

im aware that some metal fittings can be class 2. might just be the council that doesnt want class 1 lights in bathrooms tho

 

[keenbutconfused]

I am assuming that some if not all of you of you are professional electricians. Wish I had a job that I enjoyed talking about after work.

From the isolator switch in my bathroom there is a t&E cable that links to the shaver socket. the tc&E also comes into the shaver socket and is linked to another tc&E cable that then leaves the socket. I am assuming that it has been done like this as this was the easiest route from the isolator to the fan. the earths from all these cables are joined together to the metal case behind the socket. A single green and yellow sleeved earth cable then leads from the socket downwards.

I have assumed that this is for the supplementary bonding on the washbasin, radiator and bath taps. Does this sound likely.

As you know the earth cable that comes into the bathroom to the pull switch goes no further into the bathroom system from there.

If I rewire as Andrew2022 suggested, the supplementary bonding will then be connected back up to the shaver socket and hence to the earth in the pull switch. Is this correct as I had heard that the supplementary bonding shouldnot be connected back up to the CU?

Also I have one of those screwdrivers that lights up when a connection is made. If I disconnect the power and touch one end to the earth in the shaver socket and touch the taps then can I assume that if it lights up then the taps are attached in some way to the earth cable in the shaver socket?

 

[ban-all-sheds]

I am assuming that some if not all of you of you are professional electricians.

Yes and no...

A single green and yellow sleeved earth cable then leads from the socket downwards.

I have assumed that this is for the supplementary bonding on the washbasin, radiator and bath taps. Does this sound likely.

Yes.

If I rewire as Andrew2022 suggested, the supplementary bonding will then be connected back up to the shaver socket and hence to the earth in the pull switch. Is this correct as I had heard that the supplementary bonding shouldnot be connected back up to the CU?

It is correct, and must be done. The wiring regulations require local supplementary bonding conductors to connect together the terminals of the protective conductors of each circuit supplying Class I and Class II equipment in zones 1, 2 or 3, and extraneous-conductive-parts in those zones. (i.e. pipes/taps/radiators etc, if the plumbing is copper, not plastic).

Because of that there is indeed a path back to the CU - it's not that this shouldnt happen, it's that there is no requirement to connect the local supplementary bonding cable (i.e. the one that in your case runs down from the shaver socket and hopefully on to all the pipes/taps/radiators etc) back to the CU earth.

This is a good overview: http://www.niceic.org.uk/downloads/NL139supp.pdf

This talks about the definition of extraneous-conductive-parts: http://www.niceic.org.uk/downloads/E169-9.pdf

This looks at the issues surrounding plastic pipes: http://www.iee.org/Publish/WireRegs/EarthingPlasticPipes.pdf

Also I have one of those screwdrivers that lights up when a connection is made. If I disconnect the power and touch one end to the earth in the shaver socket and touch the taps then can I assume that if it lights up then the taps are attached in some way to the earth cable in the shaver socket?

No - that's not how those things work - they light up when one end is connected to something live and the other end to anything where enough current can leak away to earth - have you never noticed how it lights up just through you holding it and touching the blade to something live? If it lit up doing the test you propose you should be very afraid...

And they are pretty useless things anyway - if yours is OK as a screwdriver than keep it, otherwise consign it to the bin and buy a proper multimeter.

And it's a multimeter on a low resistance range that you need to check for continuity between your extraneous-conductive-parts and the circuit earths.

 

[keenbutconfused]

Have to say I have always found this neone screwdriver rather baffling.

if I put my finger on the non- tip end then with my other hand holding a paper clip touch the tip to the paper clip then it lights. I presumed that that was telling me that ther was a complete circuit there.

Now if I touch that non-tip end and touch a lamp that I own that is not pluged in it also lights. This lamp can't be live though as it is not plugged in.

It also lights up when I touch the screws in plastic light switches but then also lights up when I touch it to a metal stand that is used to keep hot pots of the kitchen counter surface (this stand has rubber feet and is definitely not connected.

Just out of interest is there an explanation for this behaviour.

 

[securespark]

was told at work last year that bathroom fittings should be class 2 and were not allowed to install class 1.

Firstly, I don't believe that's true.

Secondly, metal does not mean Class I.

Amazing!!

I said all of that without moving my lips! Gottle of geer!

 

[securespark]

Think you may have a neon driver that also does continuity, but badly, if it lights up on the pot stand.......!

 

[ban-all-sheds]

Maybe his house is directly under an EHT transmission line..