G
Geoffsd
It may get a little hotter than we want tho
That's true - but it is just over half the csa of 6mm² which some think cannot live with a 40A shower and mcb.
Discuss 9.5 kw shower on 6mm ? in the UK Electrical Forum area at ElectriciansForums.net
It may get a little hotter than we want tho
Why do you think it necessary to make up your own rules rather than use the regulations?
this is all very well...but 10mm cable run method 101=36A....method 102=47A....but its method 103 that could present probs....as its down to 32A....I have a rule where anything over 8KW I install a 10mm cable.
There are some new grants available in Wales recently where they are installing insulation free of charge for people on benefits, they even installing between floors and in stud walls for houses with energy rating of E or below.
I will not risk installing a 6mm cable or keeping a 6mm cable for a 9KW shower when next week they could get this grant and put insulation ontop of the cable changing the max current it will take.
If they insist that they wont allow me to put a 10mm cable in then they sign an advisory form stating that the cable must be upgraded if anything happens around the cable - i.e. insulation in loft or walls.
What ever happens cover your back!
At last! Someone else who undestands the shower ratings and the effects of Ohms Law when the voltage is reduced!
Except that I think you made an arithmetic error:
(9500 x 230) / 240 = 9100KW
Ib = 9500/240 = 39.6A
or
Ib = 9100/230 = 39.6A
So, fine on a 40A for non-continuous use (or leave a space on at least one side of the MCB)
At last! Someone else who undestands the shower ratings and the effects of Ohms Law when the voltage is reduced!
Except that I think you made an arithmetic error:
(9500 x 230) / 240 = 9100kW
Ib = 9500/240 = 39.6A
or
Ib = 9100/230 = 39.6A
So, fine on a 40A for non-continuous use (or leave a space on at least one side of the MCB)
240v | 230v |
7.5kW | 6.9kW |
8.5kW | 7.8kW |
9.0kW | 8.2kW |
9.5kW | 8.7kW |
9.8kW | 9.0kW |
10.8kW | 9.9kW |
Just reading through this thread and saw this and made me chuckle lol.... 9100Kw now thats one hot shower!!!! + the calcs are totally wrong too.
No offense pc electrics i know it just an error but funny with re' of the point of your post.
I'm sorry but that's not how it works.
The resistance of the element is the only constant.
A 9500W shower @ 240V is as you say 39.6A
To find the 230V wattage it is necessary to find the resistance of the element which is 6.06Ω
At 230V 6.06Ω results in 8724W.
So 8724 / 230 = 37.9A
Here's the calcs you need to be doing if converting...a 240v rated shower to 230v
9500/240 = 39.58A
This will mean the element resistance is :-
240v/39.58A = 6.06ohms
To convert this to a 230v supply the element resistance must remain the same thus:-
230v/6.06ohms = 37.95A Which gives a KW rating of:-
230v x 230v /6.060hms = 8.73Kw
alternate method;
230v x 37.95A = 8.73KW
Sorry Geoffd and moses just seen you've already shown this but at least with a few posts now showing it it might sink in - something that i would class as first year basics.
On the contrary, there is a very important point to be made here and all electricians must understand that while the nominal volts in UK are 230V, the actual volts are anywhere from 255V to 218V as already mentioned on in this thread.
For a 9500W shower for example, the currents are:
at 218V = 35.96A
at 230V = 37.93A
at 240V = 39.58A
at 252V = 41.56A
If you are consistently getting 252V at a property, and you install a 40A breaker for a 9.5Kw shower, then you will be called back to rectify the tripping shower, although you can try to explain to the customer as much as you like that the BRB states......, the nominal voltage is supposed to be ........ etc etc.
Reply to 9.5 kw shower on 6mm ? in the UK Electrical Forum area at ElectriciansForums.net
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