UK ariston water heater install

[littlespark]

Severe case of de ja vu there.
Swear I read the same thing three times...

+1 for 10mm and rcd protection.

 

[johnmann91]

A couple of questions if I may...

What type of cable is it going to be run in?
How loaded are the other 3 cables?

cable will be 10mm T&E.the other cable runs are 2.5mm T&E one of which has 2 double sockets on it ,one of which has microwave plugged in and the other has the washing machine and tumble dryer .and the other cable has a single socket doing nothing and a double rcd socket which will have a dishwasher plugged in.

 

[johnmann91]

If going with a separate CU then any of the "shower" units should do fine - 63A RCD and 40 or 45A MCB.

You'll want one with a good amount of space in it to nicely terminate 10mm, but the current metal ones do tend to have more space in now than they used to.

It might pay to get a 2 or 3 way one with blanks to give you the extra space (and the possibility of adding maybe a 6A or 16A in the future.

thats good news ,ive checked and there is room in the henley block for another set of tails so i can fit a 63Arcd with a 40Amcb shower unit ,wont need expansion in future ,just as long as the 40A mcb will be enough otherwise ive got to find a 45 and it most likely wont be same make ,and i dont want to go up to a 50 for the sake of matching it all

 

[loz2754]

cable will be 10mm T&E.the other cable runs are 2.5mm T&E one of which has 2 double sockets on it ,one of which has microwave plugged in and the other has the washing machine and tumble dryer .and the other cable has a single socket doing nothing and a double rcd socket which will have a dishwasher plugged in.

Thanks.
I did a Procerts calculation using the info you gave, which points to 10mm minimum.

 

[Rockingit]

The pedant in me needs to point out that Uo is 230, not 240....... (although you're better off using 240-243 for real-life purposes!)

 

[loz2754]

The pedant in me needs to point out that Uo is 230, not 240....... (although you're better off using 240-243 for real-life purposes!)

Indeed. I was also going to point this out. Using 230 volts results in 41.3 amps, so a 45 or 50 amp OCPD would be needed.

 

[Rockingit]

Indeed. I was also going to point this out. Using 230 volts results in 41.3 amps, so a 45 or 50 amp OCPD would be needed.

Which in itself raises an interesting question...... should we actually ignore the 'official' nominal voltage when doing cable calcs and instead use what we all know is realistic in order to err on the side of caution??

 

[MJPD29]

John with all due respect should you not be capable of designing this circuit yourself if you are carrying out the work?

 

[loz2754]

John with all due respect should you not be capable of designing this circuit yourself if you are carrying out the work?

This I was also thinking

 

[johnmann91]

thankyou all for the advice ,i will be running 10mm T&E from a seperate CU which will have a 2 pole 63A 30mA RCD device and a 50A MCB Type B fed from a seprerate set of 16mm tails from the henley block