Shower calculations

[riz99]

Hi everyone again! I was wondering if anyone could help me work out what calculations I need to make to work out the shower size? Thank you

 

[PrenticeBoyofDerry]

We might be able to, what is you are trying to find out?
The size of an already installed shower or what shower you can run safely and efficiently on an existing circuit?
or have you got a shower already but not installed and wanting to know the correct fuse and cables sizes?
More detail needed!

 

[riz99]

Sorry it's to replace one that's already there! It's running off a 32amp type b breaker on 6mm cable! I no you use ohms law & your cable count I just can't remember the exact way for working it out!

 

[ajrobb]

32A * 230V = 7360W = 7.36kW

 

[cumbriahandyman]

Sorry it's to replace one that's already there! It's running off a 32amp type b breaker on 6mm cable! I no you use ohms law & your cable count I just can't remember the exact way for working it out!

Ohms law?

Tell us the tech details of your new shower.

How is the cable run, through insulatied wall or clipped etc, how long is the cable...

 

[PrenticeBoyofDerry]

Try these online calculators, should help you determine what is needed.
http://www.onlineconversion.com/ohms_law.htm
http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

 

[riz99]

Try these online calculators, should help you determine what is needed.
http://www.onlineconversion.com/ohms_law.htm
http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html[/QUOTE]

Thank you for those sites, the top one jogged my memory back an't had to use for ages lol cheers again

 

[PrenticeBoyofDerry]

Thank you for those sites, the top one jogged my memory back an't had to use for ages lol cheers again

No probs pal, Happy to be of assistance

 

[ban-all-sheds]

Hi everyone again! I was wondering if anyone could help me work out what calculations I need to make to work out the shower size? Thank you

The specific heat of water is 4.19J/gK, i.e. it takes 4.19 Joules to raise the temperature of 1g of water by 1°C

1W is 1 Joule per second.

So you need to decide what temperature rise you want, at what flow rate, and you'll then be able to work out what size of shower you need to deliver that performance.

 

[ajrobb]

Existing 32A CB should be OK for 7kW. To heat water by 33°C (from winter 5°C to 38°C), 7*60/4.19/33 is a relative trickle of 3 litre/minute.

Is any diversity allowed for electric showers?

Is replacing an electric shower notifiable to Local Authority Building Control?

 

[echoes]

Is any diversity allowed for electric showers?

No - there is nothing diverse about the load of an electric shower.

Is replacing an electric shower notifiable to Local Authority Building Control?

No - it's not a new circuit, or an extension of a circuit. Clearly the risks associated with replacing ,say, a 7kW electric shower with a 10kW one are much less than those associated with someone adding a light fitting in the bathroom, according to that document's authors, and therefore will help create 'sustainable' 'communities' (!)

 

[ban-all-sheds]

Clearly the risks associated with replacing ,say, a 7kW electric shower with a 10kW one are much less than those associated with someone adding a light fitting in the bathroom, according to that document's authors, and therefore will help create 'sustainable' 'communities' (!)

It's very unlikely that such a replacement would not be notifiable.