Shower Room Electrics

H

Heinz57

Hi all,

I have already conducted reasearch into this, using both a search on here and other sources found from Google, but I am posting because I want to make sure I'm on the correct page.

So, very soon we will be completley re-doing our shower room. I have some questions about the electrics.

Firstly is the extractor fan. There is talk of having it on the same switch as the light switch (Although I personaly don't think this is a good idea, I mean what if the shower is used mid day? Then that means the lights got to be on, which is a waste of time and electricity. Anyway, here is the circuit diagram of how I think it needs to be done...

View media item 34216
The existing lighting feed and switch cable will be used, and they are in the old red and black colours. Also note that I have not included the earth on the diagram, for clarity. But they will of course be there when the job is done.
For the lights, there is three of these, 12v downlights powered from a transformer, daisy chained together. I will use 1mm 2+E for these.
For the extractor fan, I will run 3+E. I think the thickness I need is 2mm?
I havn't seen it on any others, but I can't help but think some form of FCU is required?

These are the switches that I will most likley use...
http://www.screwfix.com/p/volex-pull-sw-chrome-6a/20542?_requestid=129912
http://www.screwfix.com/p/volex-fan-isolating-sw-wht-ins-pc-angled/80113?_requestid=130045

If the light and fan will be on a differant circuit, I'm assuming the circuit diagram is the same (Minus the lights of course!). In this case, will the fan isolator be excluded and the pull cord switch act as the isolator?

Right the shaver socket, this needs to be moved from its current location (Staying on the same wall, but its being moved lower. Its far too high) I think the best way to do this would be to extend the current cable, and burry a JB inside the wall at the location the socket currently is. Am I right or wrong?

Thanks in advance for any constructive help and advice.

Heinz
 
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H

Heinz57

Probably not.

Yes I know we should. But its not me in charge of the job
 
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And it should not be you in charge of the electrics.


Then that means the lights got to be on, which is a waste of time and electricity. Anyway, here is the circuit diagram of how I think it needs to be done...

View media item 34216
That diagram shows exactly what you said you didn't want - the fan and the lights on the same switch.


I think the thickness I need is 2mm?
No such thing.

How can you be competent to design, install and test electrical circuits if you don't even know what cable sizes are available?

Have you asked the person in charge of the job how they plan to ensure that the electrical work complies with P1?


I havn't seen it on any others, but I can't help but think some form of FCU is required?
Where, and for what purpose?


If the light and fan will be on a differant circuit, I'm assuming the circuit diagram is the same (Minus the lights of course!). In this case, will the fan isolator be excluded and the pull cord switch act as the isolator?
What does the isolator do?

What function will be missing if you don't have it?


Right the shaver socket, this needs to be moved from its current location (Staying on the same wall, but its being moved lower. Its far too high) I think the best way to do this would be to extend the current cable, and burry a JB inside the wall at the location the socket currently is. Am I right or wrong?
You're wrong.

Please get an electrician.


Thanks in advance for any constructive help and advice.
This advice is constructive - you don't know enough about electrics to be doing electrical work, so you need to get someone who does.
 
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Heinz57

That diagram shows exactly what you said you didn't want - the fan and the lights on the same switch.

Yeah I know. It is only my personal opinion that it shouldn't be on the same switch. I just think it would be better if they were both separate (I mean whats the point in having lights on, mid-day in a room that gets plenty of natural light? Wasting electricity isn't it?) But those specifying the job want differant. It still isn't decided though.

I think the thickness I need is 2mm?
No such thing.

How can you be competent to design, install and test electrical circuits if you don't even know what cable sizes are available?

That is 2mm² Which according to one of the sources I read, it is what I require.

I am quite aware of differant cable sizes.

Have you asked the person in charge of the job how they plan to ensure that the electrical work complies with P1?

The person in charge hasn't even heard of part P.... The person in charge of the job is the same person who thinks just turning off a light at the wall switch is enough to safley work on the circuit.

If the light and fan will be on a differant circuit, I'm assuming the circuit diagram is the same (Minus the lights of course!). In this case, will the fan isolator be excluded and the pull cord switch act as the isolator?
What does the isolator do?

What function will be missing if you don't have it?

The isolator gives the apility to isolate the exractor. The current extractor fan uses a pull cord switch. The switch must be acting as the isolator. There is not one within the room, and deffinatly one one hidden in the attic above.

Right the shaver socket, this needs to be moved from its current location (Staying on the same wall, but its being moved lower. Its far too high) I think the best way to do this would be to extend the current cable, and burry a JB inside the wall at the location the socket currently is. Am I right or wrong?

You're wrong.

Yes. I have seen posts elswhere about burying the JB in the wall. Some others have said that it wouldn't be a good idea because of someone drilling into the wall. I am skeptical myself. Hence why I posted.

The better option would be to run a complete new cable down the wall. It would involve having to cut some form of access channel in, but everywhere is being re-plasterd so shouldn't matter too much.

EDIT - fixed broken quotes
 
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It is only my personal opinion that it shouldn't be on the same switch.
I personaly don't think this is a good idea, I mean what if the shower is used mid day? Then that means the lights got to be on, which is a waste of time and electricity. Anyway, here is the circuit diagram of how I think it needs to be done...


That is 2mm² Which according to one of the sources I read, it is what I require.
1) Which source was that? Did they suggest where you might buy such cable?
2) Why are you not competent to work out for yourself what size cable you need?


I am quite aware of differant cable sizes.
Then why are you talking about a size which does not exist?


The person in charge hasn't even heard of part P.... The person in charge of the job is the same person who thinks just turning off a light at the wall switch is enough to safley work on the circuit.
Tell them about Part P.

Then walk away and have absolutely nothing to do with the work.


The isolator gives the apility to isolate the exractor. The current extractor fan uses a pull cord switch. The switch must be acting as the isolator.
How does the switch do that? (HINT - compare the number of poles that the switch has with the number of live conductors going to the fan).


Yes. I have seen posts elswhere about burying the JB in the wall. Some others have said that it wouldn't be a good idea because of someone drilling into the wall.
Where has somebody said that?

It's not the reason. Did none of the posts you read talk about inaccessible JBs?


Tell the muppet in charge that they need to get a competent electrician.
 
H

Heinz57

1) Which source was that? Did they suggest where you might buy such cable?
2) Why are you not competent to work out for yourself what size cable you need?

http://www.ultimatehandyman.co.uk/diy/electrics/extractor_fan/shower_extractor_fan_fitting.htm

That is the source I got the circuit diagram from.
I can't find the link about the cable. Although ok I may have but 2 instead of 2.5. But I am quite cabable of concluding 2 should be 2.5 when I'm in the shop purchasing the cable.

The isolator gives the apility to isolate the exractor. The current extractor fan uses a pull cord switch. The switch must be acting as the isolator.
How does the switch do that? (HINT - compare the number of poles that the switch has with the number of live conductors going to the fan).

Yes there are three connections on the isolator (L1, L2 and N) But like I said, there isn't currently one in there at the moment. Which is whats raising my few questions (The current circuit is the original that was installed when the house was built, about 15 or 16 years ago. We havn't touched it))

Tell the muppet in charge that they need to get a competent electrician

If you don't mind the muppet you are reffering to is my brother.

I posted this topic to seek clarification on a circuit diagram I had sought elswhere. Not to begin a discussion as to wether or not I should be doing my own DIY job. Thank you for your concern but I know what works I am amd am not cabable of doing.
 
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That is the source I got the circuit diagram from.
It doesn't matter where you got it from.

You said you didn't think the fan should be controlled by the light switch, went on about why, and then said "here is the circuit diagram of how I think it needs to be done" and presented a diagram of the fan controlled by the light switch...


I can't find the link about the cable. Although ok I may have but 2 instead of 2.5. But I am quite cabable of concluding 2 should be 2.5 when I'm in the shop purchasing the cable.
1) What is the load of the fan?

2) What is the rating of the protective device for the circuit?

3) Why do you think you need 2.5mm² cable?


Yes there are three connections on the isolator (L1, L2 and N) But like I said, there isn't currently one in there at the moment.
You did say that.

You also said "The current extractor fan uses a pull cord switch. The switch must be acting as the isolator. "

So - how is the switch acting as an isolator?


If you don't mind the muppet you are reffering to is my brother.
I don't mind.

Your brother has never heard of Part P.

Your brother thinks that turning a light switch off makes it safe to work on the circuit.

Your brother is involving someone just as incompetent as him in the electrical work for this shower room.

Your brother is a muppet.


I posted this topic to seek clarification on a circuit diagram I had sought elswhere. Not to begin a discussion as to wether or not I should be doing my own DIY job.
You've had a bonus then.


Thank you for your concern but I know what works I am amd am not cabable of doing.
Do you know that you're not capable of doing, or advising on the doing of, the electrical work in this shower room?

Tell your brother that he needs to get a competent electrician.
 
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For the lights, there is three of these, 12v downlights powered from a transformer, daisy chained together.

How far apart are they? What size lamps are you putting in? Have you calculated (or are you even aware of) volt drop on the secondary side of the transformer?

Why do you think an extractor fan requires a cable twice as thick as that supplying the lighting?
 
H

Heinz57

You said you didn't think the fan should be controlled by the light switch, went on about why, and then said "here is the circuit diagram of how I think it needs to be done" and presented a diagram of the fan controlled by the light switch...

For the third time, it is only my personal opinion that they should be on two separate switches. However those specifying the job might want differant, and have them on the same switch. They still don't yet know which they want.

The diagram was presented so someone could confirm it correct. For just in case they want them on the same switch.

Yes there are three connections on the isolator (L1, L2 and N) But like I said, there isn't currently one in there at the moment.
You did say that.

You also said "The current extractor fan uses a pull cord switch. The switch must be acting as the isolator. "

So - how is the switch acting as an isolator?[/quote]

Well its the only solution I could think of. I don't know why the current circuit is the way it is. It was installed when the house was built 15 odd years ago. I don't know maybe the regs were differant then, maybe the electricians who installed it were cutting corners. Who knows what they were doing. But there deffinatly isn't an actual isolator switch itself on the current circuit.

How far apart are they? What size lamps are you putting in? Have you calculated (or are you even aware of) volt drop on the secondary side of the transformer?

Why do you think an extractor fan requires a cable twice as thick as that supplying the lighting?

Thanks for your responce.

Distance, well the room isn't extreamly long. The won't be too close together or at the same time too far apart. They would probably be around 2ft apart I should think. Too allow for decent coverage of the space.

The fixtures are rated at 50W max.

Now I've done some calculations, for both 12v and 240v lights. I got less than a volt dropped (around 0.8v). Which doesn't seem right to me. Its quite low isn't it?

Well like I say, it was on another source where it said about the cable. 2.5 does seem quite hefty to me too.
 
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For the third time, it is only my personal opinion that they should be on two separate switches.
And you expressed it clearly and firmly. So for the third time, why did you then present a diagram, conflicting with that clearly and firmly expressed opinion saying "here is the circuit diagram of how I think it needs to be done"?


The diagram was presented so someone could confirm it correct.
Why? Don't you understand it?


Well its the only solution I could think of.
Is it a solution?

Could the switch be acting as an isolator?


Why do you think an extractor fan requires a cable twice as thick as that supplying the lighting?
That's the second person to ask you that.

Are you going to answer it?


Now I've done some calculations, for both 12v and 240v lights. I got less than a volt dropped (around 0.8v). Which doesn't seem right to me. Its quite low isn't it?
Is it?

Is low good or bad?

Is it low for both 12V and 240V?

What are the limits at 12V and 240V?


Well like I say, it was on another source where it said about the cable. 2.5 does seem quite hefty to me too.
So why use it?

Why don't you know how to work out what cable size is needed?


When are you going to accept that you really can't cope with any of this?

You can't read trivial circuit diagrams.

You don't know how to extend cables properly.

You don't understand isolation requirements.

You do calculations but don't understand what you're doing or what the results mean.

You don't know what sizes cables come in.

You read recommendations for cable sizes but can't explain why they might be right or wrong.

You say you know you should get an electrician but here you are, still blundering about.

Stop.

Now.

Get a competent electrician in, FGS.
 
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Indeed it does, but the OP is going to use that size for the fan, and 1mm2 for the lighting.
 
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Indeed it does, but the OP is going to use that size for the fan, and 1mm2 for the lighting.

More importantly, if the OP or his brother carry out this installation in any manner they will be responsible for a possible fatal consequence. Even if he had the theory right he is not qualified to test and sign off the installation.
 

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