Electric showers.

[Hugh Jaleak]

Firstly apologies if this has already been covered, have searched without success.

What is the maxium kW that can safely be put on a 6mm2 cable? A friend has a Gainsborough Sovereign shower that is giving pretty poor flow. He's also got a combi that is playing up for a pastime..... Washing in cold water is not funny at this time of the year.

I've not looked at the job yet, presuming there's a 6mm cable there. If not, he'll need an electrician because i'm not touching it! Have looked at Screwfix, smallest shower they do is 8.5 kW. I would think this would be too much on 6mm cable and 32A breaker. Id be grateful if someone could advise me please!

Many thanks, Hugh.

 

[RF Lighting]

What is the maxium kW that can safely be put on a 6mm2 cable?

Depends how the cable is installed.

 

[securespark]

And how long it is.

 

[Softus]

If the cable length is no more than 41 metres, and if it's installed in unfavourable conditions, then 6mm will safely support a 7.6kW shower (rated at 240V).

 

[stargazer]

And if it is run entirely in favourable conditions, in free air with no de-rating factors (highly unusual), 6mm will support 12KW.

I would reckon as a rule of thumb 6mm is in order for an electric shower up to 8.5KW, any higher use 10mm. But of course you must consider the installation methods and do the maths. If you’ve got the opportunity, install 10mm in any case for future-proofing.

Hugh, there is some interesting reading for you here particularly Example 3.3.

 

[Hugh Jaleak]

Many thanks to all. Stargazer that little bit of light reading is interesting, afraid as a mere plumber i'll leave it to the experts!

I have since discovered my friend is renting the place, landlord has put cheap combi in, currently only working in fits and starts. Lack of hot water and landlords lack of urgency regarding fixing anything led my friend to take matters into his own hands so they could at least wash!

However, it not being my friends property I am reluctant to get involved. Think I'll advise him to hound the letting agents regarding getting at least something sorted. Thanks again to all.

Hugh.

 

[ricicle]

And if it is run entirely in favourable conditions, in free air with no de-rating factors (highly unusual), 6mm will support 12KW..

Not quite though...

 

[stargazer]

And if it is run entirely in favourable conditions, in free air with no de-rating factors (highly unusual), 6mm will support 12KW..

Not quite though...

The last time I put my multimeter across my phase and neutral it read 240V

 

[ban-all-sheds]

that little bit of light reading is interesting, afraid as a mere plumber i'll leave it to the experts!

Electrics is just connecting up wires - how hard can it be.....

 

[stargazer]

Darn tootin’

 

[stargazer]

And how long it is.

I get no complaints

But tbh, I wish it was a little longer

 

[Softus]

And if it is run entirely in favourable conditions, in free air with no de-rating factors (highly unusual), 6mm will support 12KW.

Clipped direct to free air?

Not quite though...

The last time I put my multimeter across my phase and neutral it read 240V

230+10%=253VAC --> 11.64kW.

 

[stargazer]

And if it is run entirely in favourable conditions, in free air with no de-rating factors (highly unusual), 6mm will support 12KW.

Clipped direct to free air?

Not quite though...

The last time I put my multimeter across my phase and neutral it read 240V

230+10%=253VAC --> 11.64kW.

OK, point taken.
Task for today: Must update my Table 4D2A.

 

[ban-all-sheds]

2nd task - stop using 4D2A for twin & earth.....

 

[stargazer]

2nd task - stop using 4D2A for twin & earth.....

4D5A