In theory a larger fuse is required and would avoid the overheating.
In reality it may not be possible as the fusebox may not be suitable for fuses larger than 30A.
Electric shower problems
- Thread starter Krustyzidane
- Start date
In reality it may not be possible as the fusebox may not be suitable for fuses larger than 30A.
Sponsored Links
Indeed, since I doubt that 33.3A or 35.4A through a 30A fuse would bring about any melting.
Kind Regards, John
Indeed One of our flats had a 7KW shower on 30A and 4mm², a new tenant decided to up-grade to a 9.5KW, it was found on PIR a whole year later, by then the ends of the cable [all 4] were lovely and crispy and had to be replaced along with the 'melted' CU. But the fuse never blew.
And chances are, that newer 8.5KW heater is rated for 230V and when run on 240V would potentially be more like 38A [or 40A at 250V] and still the fuse will not blow.
Sponsored Links
Depends on it's country of origin. Those that were on 220V do tend to quote at 230V and I fairly regularly find currents higher than predicted for this reason.
Do you mean bought from dubious sources?
It doesn't, of course, alter the 'predicted' or expected current.
It doesn't, of course, alter the 'predicted' or expected current.
You mean the European union? Well now you mention it...
Of course it does, a unit rated for say 10KW at 230V has a predicted current of around 43A but run it on 240V and it will be 10.88KW and 45.3A.
It used to be a BIG problem when we had loads of forces stationed in Germany and their supply was 220V, they brought stuff over by the lorry load, I recall popular mains water pressure water heaters rated at 12 KW being used as replacements for the big old multipoint gas heaters, I regularly failed to measure the current on my AVO as the clamp accessory for it only went up to 60A and it was often on the stop, 60A was quite typical.
Last edited:
Well, I did mean the likes of Ebay and products not meant for sale in Britain.
- Joined
- 16 Sep 2007
- Messages
- 1,908
- Reaction score
- 163
- Country
If you buy a Triton, Mira or Gainsborough shower, the rating is at 240V.
The last Gainsborough I checked came out a little high, so either it was rated at 230V or it was a heavier heater than quoted. My present 10.5KW Triton at 243V drew 41A so less than10KW.
Are we talking at crossed purposes?
I (and I think Aptsys) are talking about what the manufacturer states on the box (and internal label), not what you may measure.
This may be 9.5kW in large print for advertising. In smaller print (and internal label) it will state 9.5kW @ 240V, (and likely also on the label 8.7kW @ 230V).
These figures do not match exactly according to Mr.Ohm so I presume they are near enough for manufacturing tolerances which might vary slightly.
If they make an element with a resistance of (in this example) ~6.06Ω, they could quote whatever voltage and power they wanted but it will still be the same shower. Obviously they will quote what the user is likely to actually have, ~240V plus (for Winston) the nominal 230V.
You should have measured the resistance cold.
What were you trying to discover?
I don't think I have ever measured the resistance of a shower element but immersion heater elements are usually near the expected resistance when cold - ~19Ω for 3kW @ 240V.
I (and I think Aptsys) are talking about what the manufacturer states on the box (and internal label), not what you may measure.
This may be 9.5kW in large print for advertising. In smaller print (and internal label) it will state 9.5kW @ 240V, (and likely also on the label 8.7kW @ 230V).
These figures do not match exactly according to Mr.Ohm so I presume they are near enough for manufacturing tolerances which might vary slightly.
If they make an element with a resistance of (in this example) ~6.06Ω, they could quote whatever voltage and power they wanted but it will still be the same shower. Obviously they will quote what the user is likely to actually have, ~240V plus (for Winston) the nominal 230V.
It could be but I have never seen one where only 230V is stated.
You should have measured the resistance cold.
What were you trying to discover?
The resistance of the element will increase with the temperature so I would consider that normal.
I don't think I have ever measured the resistance of a shower element but immersion heater elements are usually near the expected resistance when cold - ~19Ω for 3kW @ 240V.
If that's true, it's a bit daft (and misleading), isn't it? When one powers up a shower or immersion element, it is only a second or two before it reaches operating temperature, and people will be interested in knowing the power consumption when it is operating, won't they (and not what power it would consume if, hypothetically, it could operate without rising in temperature)?!
Kind Regards, John
Do you disagree?
As it will be less than they expect, they may not be too upset.
As it will be less than they expect, they may not be too upset.
I certainly agree with the physics of what you said - i.e. that the resistance of an element will be higher, and hence the power (at any particular voltage) will be lower, when the element is 'working' (i.e. hot) than when it is cold.
What I can't agree or disagree with (since I don't know, without doing some measurements) is your suggestion (as I understand it) that the manufacturers may state the 'power' (at a particular voltage) which would only be true if the element were cold (i.e. 'not working). However, as I said, if that is what they do, I would consider it to be both daft and misleading.
Kind Regards, John
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
