Installing new shower

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Hi,
i'm currently in the process of removing and installing a new bathroom suit plus shower. the old shower is a mira essential not sure of kw and is supplied from the old style consumer unit with 30amp fuse, i think the cable is 6mm, the new shower is 8.5kw, assuming that the old cable is 6mm would this and anything else need replacing, if so what.
thanks.
 
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blackbob said:
supplied from the old style consumer unit with 30amp fuse
Is that a rewireable fuse?

i think the cable is 6mm, the new shower is 8.5kw, assuming that the old cable is 6mm...
Does the cable run through any insulation?

...would this and anything else need replacing, if so what.
thanks.
Depending on your answer to the above questions, you may well need to change the CU, as well as the cable.
 
8.5kw @ 240V = 35.4A. Most older consumer units were not designed for / are not capable of supplying more than 30A per fuseholder.
 
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Softus said:
blackbob said:
supplied from the old style consumer unit with 30amp fuse
Is that a rewireable fuse?

i think the cable is 6mm, the new shower is 8.5kw, assuming that the old cable is 6mm...
Does the cable run through any insulation?

...would this and anything else need replacing, if so what.
thanks.
Depending on your answer to the above questions, you may well need to change the CU, as well as the cable.

Yes 30 amp rewirable.

No insulation but will be channeled in then plastered and tiled over in the shower section.
 
What is the make of the consumer unit and current rating of the main switch?
 
davy_owen_88 said:
8.5kw @ 240V = 35.4A. Most older consumer units were not designed for / are not capable of supplying more than 30A per fuseholder.

So can the fuse be up graded or is it a new cu, is the wire ok.
 
blackbob said:
Yes 30 amp rewirable.

No insulation but will be channeled in then plastered and tiled over in the shower section.
Even if you were able to upgrade to a 40A fuse carrier, your cable would have to be rated to at least 55A, and 6mm² cable in conduit in plaster isn't.

In fact, even 10mm² is borderline, so I'd say you need to change the protective device, which might mean a new (or supplementary) CU.
 
Will try and post pics when i find out how, it's a metal wylex box with 4 fuses wired at the moment with 3X30 amp and 1X15amp.

thanks
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Underrated cable, outdated impractical consumer unit with limited futureand, no RCD ...

Common sense and good practise dictate upgrade both CU and Cable.. Oh and Supplementary bonding of course. Lets not try and suggest anything otherwise, I wouldn't anyway.
 
equitum said:
Common sense and good practise dictate upgrade both CU and Cable.
Why? And how do you expect a novice to accept that without any technical justification?
 
Why ? For all the reasons already posted.

Softus said:
blackbob said:
Yes 30 amp rewirable.

No insulation but will be channeled in then plastered and tiled over in the shower section.
Even if you were able to upgrade to a 40A fuse carrier, your cable would have to be rated to at least 55A, and 6mm² cable in conduit in plaster isn't.

In fact, even 10mm² is borderline, so I'd say you need to change the protective device, which might mean a new (or supplementary) CU.

So a "novice" has can appreciate from your post that you have applied a correction factor of 0.725 for a rewirable fuse??

Its not impossible to install an 8.5kw on 6mm cable on a rewirable fuse, but why would anyone recommend such an installation to a "novice" ?
Why get into a debate about what's technically feasible when the solution is all but inevitable and advisable?
 
equitum said:
Why ? For all the reasons already posted.
My "Why" was related to your assertion that common sense and good practise dictate the course of action. They don't. Unless of course you put 'all technical considerations' under the umbrella of good practise.

Softus said:
blackbob said:
Yes 30 amp rewirable.

No insulation but will be channeled in then plastered and tiled over in the shower section.
Even if you were able to upgrade to a 40A fuse carrier, your cable would have to be rated to at least 55A, and 6mm² cable in conduit in plaster isn't.

In fact, even 10mm² is borderline, so I'd say you need to change the protective device, which might mean a new (or supplementary) CU.
So a "novice" has can appreciate from your post that you have applied a correction factor of 0.725 for a rewirable fuse?
Of course not, but there's such a thing as too much information - he's free to ask for the workings.

Its not impossible to install an 8.5kw on 6mm cable on a rewirable fuse
Er, it is in this case, because of where the cable is to be run.

but why would anyone recommend such an installation to a "novice" ?
I can't answer that, because nobody has made that recommendation.

Why get into a debate about what's technically feasible when the solution is all but inevitable and advisable?
Because debate is the means by which people who don't know and understand things come to know and understand them. It's not very helpful just to say that the answer is inevitable, especially when it isn't, nor to say that the right course of action is to follow common sense, when the OP doesn't have any in this context.

And when I say 'not very helpful', I actually mean 'utterly unhelpful'. :rolleyes:
 

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