Replacing electric shower advice

[RF Lighting]

The element in the shower has a fixed resistance so as the voltage to the shower increases so does the power consumed. Each house along your street will have a slightly different supply voltage, so the same shower unit will use a different amount of power (kW) in each house. Unfortunately this is due to the laws of physics.

If you can not verify how the cable has been installed then you can not simply increase the size of circuit breaker to supply larger shower. Doing so may allow the cable to overheat while in use and it could start a fire. 6.0mm² may need to be de-reated to as low as 30A depending on installation method.

We still haven't even established yet if your wiring is actually 6.0mm². From looking at your first picture it could well be 4.0mm² but its difficult to tell for sure from a picture.

 

[ash1212002]

The element in the shower has a fixed resistance so as the voltage to the shower increases so does the power consumed. Each house along your street will have a slightly different supply voltage, so the same shower unit will use a different amount of power (kW) in each house. Unfortunately this is due to the laws of physics.

If you can not verify how the cable has been installed then you can not simply increase the size of circuit breaker to supply larger shower. Doing so may allow the cable to overheat while in use and it could start a fire. 6.0mm² may need to be de-reated to as low as 30A depending on installation method.

We still haven't even established yet if your wiring is actually 6.0mm². From looking at your first picture it could well be 4.0mm² but its difficult to tell for sure from a picture.

@EFLImpudence confirmed it will be fine, would welcome your thoughts

That 10.5kW with 45A or 50A MCB with 6mm cable will be safe

I'm assuming if the worst case scenario is applied i.e the wiring is within the insulation, clipped etc and given that its a small run it would be safe!?

 

[EFLImpudence]

RF is, in effect, asking if the present cable installation method is satisfactory.
If it is not then the present arrangement is not satisfactory.

If it is satisfactory then your proposed alterations will also be alright.

You existing shower is 9.5kW @ 240V which is 39.6A.
10.5kW @ 240V is 43.75A so the MCB has to be uprated.

6mm² cable (not in insulation or conduit) can carry 47A.
50A MCB will also be satisfactory as the shower will still be 43.75A


So, either your alterations will be alright or the existing situation needs attention anyway.

 

[ash1212002]

RF is, in effect, asking if the present cable installation method is satisfactory.
If it is not then the present arrangement is not satisfactory.

If it is satisfactory then your proposed alterations will also be alright.

You existing shower is 9.5kW @ 240V which is 39.6A.
10.5kW @ 240V is 43.75A so the MCB has to be uprated.

6mm² cable (not in insulation or conduit) can carry 47A.
50A MCB will also be satisfactory as the shower will still be 43.75A


So, either your alterations will be alright or the existing situation needs attention anyway.

Ok thanks, I'll see if i can determine if its clipped in, under insulation or within conduit and report back.

As the run is only 5m i may just consider upgrading to 10mm to be on the safe side

If the wiring is upgraded to 10mm what is the max kw shower i can go for?

 

[EFLImpudence]

As the run is only 5m i may just consider upgrading to 10mm to be on the safe side.

Ok - if you can access it.

If the wiring is upgraded to 10mm what is the max kw shower i can go for?

Clipped to surface or buried in masonry, 10mm² can carry 64A so theoretically 15kW but would also be required for a 12.5kW shower - 52A (I think that is the highest).

 

[ash1212002]

Ok - if you can access it.


Clipped to surface or buried in masonry, 10mm² can carry 64A so theoretically 15kW but would also be required for a 12.5kW shower - 52A (I think that is the highest).

Good to know thanks, I'll stick between 10.5 to 10.8kw shower with 10mm cable, would that be 45 or 50amp mcb?

I'll see if i can determine the route of the existing wiring and how its fixed otherwise it may just have to be a new run of 10mm if thats possible and accessible to achieve

 

[EFLImpudence]

10800/240 = 45A exactly.