Wiring for 8.7 kw shower?

[handyme]

Hi Help Req????

Im about to fit a new electric shower, not 100% on the cu connections. How would you do it???????????? just going to do the pre work sparks coming to connect and test............................................

What i have is E/B fuse 60a then the meter the tails to a rcob tails to a wylex consumer, with one spare way or there will be.

Do i connect a new 40amp mcb to old cu then run cable to mini cu with seprate 40a rcd or run new tails from the rcob into a spliter then to the new mini cu and main cu, then cross the earth from new cu to old cu? Then to shower via pull switch

Or is there any other way?????

Thanks

 

[securespark]

What size is/are:

The cut-out fuse? The meter? The tails? The RCD? The main switch on the CU?

Why duplicate the RCD? Or the MCB?

 

[handyme]

so what your saying is just go from the cu to the shower? Does that give a correct install?

 

[handyme]

What size is/are:

The cut-out fuse? The meter? The tails? The RCD? The main switch on the CU?

Why duplicate the RCD? Or the MCB?

60a main fuse, then the meter then to a rcbo 80a then 25mm tails to old cu will spare way?

So are you saying just add a 40a mcb to the old cu then go straight to shower, but would that not trip the whole house if there was a problem with the shower at any point??

 

[PowerTool]

MCB protects a single circuit,so won't put the power off to the whole house.
RCD will protect multiple circuits,so if earth leakage occurs and trips the RCD,all circuits covered by it will go off.

Depends what type of fault there is as to what result you get.

 

[ban-all-sheds]

60a main fuse, then the meter then to a rcdo 40a

You've got a 40A rated RCD for the whole installation??

So are you saying just add a 40a mcb to the old cu then go straight to shower, but would that not trip the whole house if there was a problem with the shower at any point??

It might well do the same if you came out of the CU into another RCD - do a search here for discriminate, discriminates, discrimination.

5 questions.

1) Do you think that you really know enough to be doing something as major as installing a new circuit for a shower?

2) You still haven't said what the rating of the main switch on the CU is - do you not realise that this is very important?

3) Are you aware of the requirements for supplementary equipotential bonding in the bathroom?

4) If/when you've installed the circuit, how do you plan to test it?

5) Are you aware that this is notifiable work, and that therefore by law you are required to notify your local council's Building Control dept before you start?

 

[handyme]

question 1?

No main fuse on the cu, old wylex. as said 60a supply fuse, meter, 80a rcbo then tails to the cu on/ off switch along a to the fuses lights ring cooker boiler spare etc.

I am quite aware of bonding but have no copper to bond to in the bathroom as it all plastic, so none req.

will have a sparks coming to test when finished.

last one? is it really.

so to the question how would you do it?

 

[securespark]

2) You still haven't said what the rating of the main switch on the CU is - do you not realise that this is very important?

No main fuse on the cu, old wylex. as said 60a supply fuse, meter, 80a rcd then tails to the cu on/ off switch along a to the fuses lights ring cooker boiler spare etc.

Not main fuse, main switch....

The old Wylex boards were never designed for any circuits greater than 30/32A, with main switch ratings of less than 100A. If it does not say what rating the main switch is, and/or the board is brown, then the board is inadequate.

If it has a wooden backplate, then even more so. The original Wylex boards were introduced in 1956. When high-powered electric showers were nowt but a twinkle....

 

[handyme]

Thank you we are now getting somewhere, yes it is a old board.

So i couldn't put a 40 mcb on that board then? then to the shower........

or would it be best to have seprate shower cu, if so do i put a spliter box between the meter and the rcbo or between the rcbo and old cu? Would that then be ok. would i need to run 25mm tails or would 10mm be ok?

Thanks

 

[baldelectrician]

if the consumer unit is that old get a new one in

 

[securespark]

No, you should NOT put a 40A breaker on that board.

I would recommend changing the CU for a split-load arrangement, and to call a Part P certified electrician to do the work.

Given the age of your CU, the spark can check that the rest of your equipment is up to scratch, check the main bonding to gas and water mains pipes too and maybe even issue a PIR so you can assess the condition of the rest of your install.

 

[ban-all-sheds]

question 1?

Yes - question 1. Be honest with yourself. This new shower is going to draw a lot of current, probably more than the rest of your house has ever drawn at any one time. You do not want to f*** up.

as said 60a supply fuse, meter, 80a rcd then tails to the cu on/ off

60a main fuse, then the meter then to a rcdo 40a then 25mm tails to old cu

I am quite aware of bonding but have no copper to bond to in the bathroom as it all plastic, so none req.

That's incorrect. Remember Q1? Supplementary equipotential bonding does not only go to extraneous-conductive-parts.

will have a sparks coming to test when finished.

Should you care, that will not meet your legal obligations.

last one? is it really.

Yes it is.

or would it be best to have seprate shower cu,

If you can't put a 40A MCB in your CU, then your options are:

1) Separate shower CU
2) New main CU
3) No new shower

if so do i put a spliter box between the meter and the rcbo or between the rcbo and old cu?

First it was 40A, then it was 80A.
First it was an RCD, now it's an RCBO.
Please make your mind up, and read Q1 again.

If you put it between the meter and the RCD, how will you isolate the supply?

Would that then be ok. would i need to run 25mm tails or would 10mm be ok?

25mm².

Talking of cable sizes - this hasn't been discussed - what size cable will you be running to the shower, and how long will it be, and where will it be installed?

 

[ebee]

Ban,
your q do you think you should be doing this .
I think we all know what the answer SHOULD be

 

[handyme]

think you all need to be honest with yourselves should you be in the game, i work for a large disabled/elderly bathroom company fitting showers every week.

your all talking s**t, you can put a 40 mcb onto that board then run it to the shower via a rcd.

Unless your calling the sparks at work a lier and we are nic reg.

Thanks for all you help. A straight forward answer would have Sufficed, the question was HOW would you do it not why or where fore you should.

thanks for all your help

 

[Spark123]

think you all need to be honest with yourselves should you be in the game, i work for a large disabled/elderly bathroom company fitting showers every week.

your all talking s**t, you can put a 40 mcb onto that board then run it to the shower via a rcd.

Unless your calling the sparks at work a lier and we are nic reg.

Thanks for all you help. A straight forward answer would have Sufficed, the question was HOW would you do it not why or where fore you should.

thanks for all your help

The fact is you have not provided the correct information for anyone to help, you may be able to connect a 40A mcb, then again you may not. You were asked on more than one occasion for the rating of the consumer unit main switch, had you answered this query then someone will have been able to give you an answer. Talking s**t - no, being careful with the information you supplied - yes.