Burnerman's shower cable question.

[Burnerman]

Some words of wisdom gents, if you please....
A guest room refurb.....out with the old 8.5 kW shower, and in with a new Grohe Tempesta of the same wattage.
It's fed with a 6 mm cable, with a run of 12 m approx. the cable isn't bunched, is on top of the insulation and has a fairly straight run.
I've run the shower for around 10 mins, and noticed the cable was a bit warm but certainly not hot. So.....
Do you think it would have been ok to fit a 9.5kW shower instead of the lower power one?
Is there a great difference between 8.5 and 9.5 kW showers performance wise?
Thanks for any suggestions
John

 

[JohnW2]

....out with the old 8.5 kW shower, and in with a new Grohe Tempesta of the same wattage. It's fed with a 6 mm cable, with a run of 12 m approx. the cable isn't bunched, is on top of the insulation and has a fairly straight run.
I've run the shower for around 10 mins, and noticed the cable was a bit warm but certainly not hot. So..... Do you think it would have been ok to fit a 9.5kW shower instead of the lower power one?

As far as the cable is concerned, 6mm² installed as you have described ought to be fine for a 9.5kW shower (and would be expected to get a little warm when the shower was being used).

What size of fuse/breaker is protecting this cable/circuit, and is it RCD protected?

Kind Regards, John

 

[Burnerman]

Thanks for your reply John! The circuit is protected by a 40 A MCB and there is an RCD. This was for the original 8.5kW shower, and I appreciate it may need upgrading if I change to a 9.5kW shower.
Unfortunately it's not possible to fit a 10mm cable due to ceiling access.
What's your opinion between the two showers....would it be worth it, do you think?
John

 

[JohnW2]

Thanks for your reply John! The circuit is protected by a 40 A MCB and there is an RCD. This was for the original 8.5kW shower, and I appreciate it may need upgrading if I change to a 9.5kW shower.

Probably not - you will very probably find that the "9.5 kW" is quoted at 240V - in which case that would amount to about 38A at 230V, hence OK on a 40A MCB.

Unfortunately it's not possible to fit a 10mm cable due to ceiling access.

You wouldn't need 10mm² for a 9.5kW shower. In fact, 6mm² cable installed as you have described would probably be OK for a 10.5 kW one (but you'd need to upgrade to a 45A MCB (assuming one were available for your CU).

What's your opinion between the two showers....would it be worth it, do you think?

Opinions vary, but I suppose that 'the higher power the better'. Having said that, although people moan about electric showers (of any power), but I have a 8.5kW one which, on the rare occasions we use it, is plenty good enough for us!

Kind Regards, John

 

[Burnerman]

Thanks John, I really appreciate your reply! Maybe I should have gone for the higher kW shower in the first place, but I can always replace it later....I'll see how it fares as it doesn't get a lot of use.
Regards
John

 

[JohnW2]

Thanks John, I really appreciate your reply! Maybe I should have gone for the higher kW shower in the first place, but I can always replace it later....I'll see how it fares as it doesn't get a lot of use.

You're welcome.

Kind Regards, John

 

[ban-all-sheds]

Is there a great difference between 8.5 and 9.5 kW showers performance wise?

About 12% better flow rate for the same Δ°.

 

[winston1]

For some reason shower powers have rocketed in recent years. 6kW was standard a few years back and one I have from that time though rarely used seems adequate. In the summer it is too hot and I switch it to "low".