9.5kw shower 6mm cable

[Bobster]

8.5kW will still require a 40A ocpd so the cable design will be the same as the 9.5kW.

No it will not. It's a fixed load application.

 

[Andy78]

No it will not. It's a fixed load application.

Well yeah, there's that too. I'll be honest, it's not an exception to the standard calcs that I use very often.

 

[Bobster]

Well yeah, there's that too. I'll be honest, it's not an exception to the standard calcs that I use very often.

Of course, in a domestic environment the savings are nominal on a new installation.

 

[johnduffell]

It doesn't matter what ocpd you put as long as the cable has a low enough zs to trip it. If you have 0.01ohm ze and the cable is 3 feet long, you could put an 63a mcb on 1.5mm cable with a bell transformer at the other end.
The issue is the rated current of the shower being suitable for the cable.

 

[Bobster]

It doesn't matter what ocpd you put as long as the cable has a low enough zs to trip it. If you have 0.01ohm ze and the cable is 3 feet long, you could put an 63a mcb on 1.5mm cable with a bell transformer at the other end.
The issue is the rated current of the shower being suitable for the cable.

Well there is a lot wrong with that statement!!

In that scenario the CPC will be destroyed in an earth fault.

Due to it being a transformer it has the potential to overload. The 63A MCB will never trip and the cable will set on fire.

 

[John tomo 1972]

So will a 8.5 kw go on a 40A with 6mm cable an be within regs as another spark put the fear of god into me by saying DONT PUT A6mm ONA 40A

 

[Bobster]

I can't confirm that without more information.

Do the calcs, VD, PFC. What the Zs? What is the cable route, is it under a ton of insulation etc etc...

Did you not ask the other "Electrician" why? Or was it the same old story of "Just don't/Because it's something we always do"

Have you done any rough calculations? You aren't going to get a hard an fast answer off someone over the internet.

 

[Deleted account]

So will a 8.5 kw go on a 40A with 6mm cable an be within regs as another spark put the fear of god into me by saying DONT PUT A6mm ONA 40A

Do the calcs with all the correction factors and you will get the answer you need.
Then if you think the spark who put the "fear of God" into you questions it , show him your results.

The worst thing you can say to him is I went on a forum and they said.....

 

[johnduffell]

In that scenario the CPC will be destroyed in an earth fault

Good point, didn't think about adiabatic/let through from the low ze. Would need a happy medium. Would anyone calculate the cpc adiabatic for a 6mm shower cable?

Bell transformer i thought unlikely to carry an overload >20A+, that's tiny, just for the door bell push, but maybe more professional opinions vary. It would catch fire itself before burning the cable

 

[brianmoooore]

Answer to this is simple. One spark knows what he's talking about, the other doesn't.

P.S. This should have John tomo 1972's last post quoted here.