24 kw water heater

[richisells]

Hi all, i have a 24 kw instant water heater from stiebel eltron which is wired in over three phases with 2.5mm wire and 16 amp fuses, the problem is after a few minutes it always trips one phase out, i had the wiring installed by a electrician but i don't believe that he really thought about the installation before proceeding, does anyone know what size fuses should be fitted to such a unit and am i correct in my thinking that i could in theory put 20 amp fuses in without causing any problems,
many thanks,
Richard.

 

[plugwash]

24KW is total 6KW per phase which at 230V works out to just over 26A.

So really you should be looking at 32A "fuses" but to safely fit those you really need larger cable.

 

[JohnD]

24KW is total 6KW per phase

3 phases at 6kW is surely 18kW total

24 would by 3 x 8.

 

[briwire]

each phase will take a little less than 32amp so you need 6mm cable and 32 amp protection.

 

[danechip]

2.4kw

http://www.stiebel-eltron.co.uk/

It's all domestic.

 

[JohnD]

what makes you think that your 2.4kW device is the one that the OP decribes as 24kW 3-phase

 

[danechip]

That it's in 2.5mm, low fusing and the site doesn't mention that size of demand.

 

[bernardgreen]

2.4kw

http://www.stiebel-eltron.co.uk/

It's all domestic.

Domestic in Europe often has three phase for heavy loads.

http://www.stiebel-eltron.de/ste_shared/pdf/data/W_5912_0_de_German.pdf

 

[JohnD]

And why is 2.4kW the same as 24kW?

 

[bernardgreen]

And why is 2.4kW the same as 24kW?

The original post included

Hi all, i have a 24 kw instant water heater from stiebel eltron which is wired in over three phases with 2.5mm wire

which danechip thought was wrong and said that it should be 2.4 kW based on the UK Stiebel Eltron website content. The German Stiebel Eltron website includes domestic 3 phase water heating equipment.

 

[JohnD]

so are we saying the OP has a 24kW instant water heater (like he says) or some other device?

 

[danechip]

And why is 2.4kW the same as 24kW?

It isn't hence the decimal.

Even in that German pdf, The highest load is only 6kW on the 90kg model.

I still believe the OP has a missing decimal.

 

[JohnD]

but OP says it's an instant water heater

 

[danechip]

My apologies. Found one...

http://www.hygienesuppliesdirect.com/products/prod147275

 

[bernardgreen]

http://www.stiebel-eltron.de/ste_shared/pdf/data/W_5827_0_de_German.pdf
for details