How many electric wall heaters can you have??

[TonyJohnson]

A domestic property with no gas supply so we are looking at wall heaters..

80Amp Bullett,
100A main switch to 80AMP/30Ma RCD to
50A Cooker
40A Shower
32Amp Full house ring
20Amp Emersion
6Amp Up lights
6Amp down lioghts

Using a 3KW/13AMP wall heater as a sample and fitting them on individual radials.... How can i calculate the amount of heaters i can have?

Any advice on types of wall heaters appreciated.

Thanks

T.

 

[Octopus]

Diversity is your friend.

Be careful .......... you need to consider the :

property type
age
insulation
size of rooms
number of windows

etc etc

 

[Pete999]

A domestic property with no gas supply so we are looking at wall heaters..

80Amp Bullett,
100A main switch to 80AMP/30Ma RCD to
50A Cooker
40A Shower
32Amp Full house ring
20Amp Emersion
6Amp Up lights
6Amp down lioghts

Using a 3KW/13AMP wall heater as a sample and fitting them on individual radials.... How can i calculate the amount of heaters i can have?

Any advice on types of wall heaters appreciated.

Thanks

T.

Tony, Hi it's not just a simple electrical calculation to tel you what heating is required, it would be very easy to say "oh stick a 2KW heater in each room, proper heat loss calcs are required. you need things like , how many air changes are required per hour/day, U values of the walls and windows, are the window double glazed for example.
If you want to do this work properly and as cost effectiveas you can, the best advice I would give you would be to contact some electrical heating companies for quotations, it may cost a bit more than you expected initially, the savings come with a properly engineered and installed electic heating system, good luck.

 

[TonyJohnson]

Thank you both for your input but i think i may have miss lead you..
The question is, how much load will the system take.

I have applied diversity and get
50A Cooker 30.6A
40A Shower 40A
32Amp Full house ring 26A
20Amp Emersion 15A
6Amp Up lights 4A
6Amp down lights 4A
These results suggest there isnt any load left but i do come across dwellings with around 4 wall heaters?

Am i missing a calc hear?
T.

 

[Octopus]

The missing calc is reality ............ the 80A DNO fuse will run at over 100A for a while and even then, I would doubt very much that you would ever see over 40A at anyone time.

The problem with diversity is that the calcs are way out of date AND we tend to have more circuits these days .............. but our consumption is typically less.

Sure if you turned on the shower, the cooker on with all plates, then all the other appliances ........................

Your issue is the size of the heaters - I tend to over spec and this gives more flexibility. Built in timers are a must

 

[TonyJohnson]

I suppose, i could simply turn everything on and take an AMP reading? This would be real time live no argument load!

I take all your points regarding choosing the correct heaters, windows, room size etc etc.

 

[Des 56]

I suppose, i could simply turn everything on and take an AMP reading? This would be real time live no argument load!

I take all your points regarding choosing the correct heaters, windows, room size etc etc.

That word reality that was used by murdoch seems to fit once again

 

[mhar]

If you can run your shower off the tank that the immersion is heating you give yourself quite a lot more scope.

 

[TonyJohnson]

Thanks Mhar but its a new elecy shower. Whats bothering me is i have done a few jobs in domestic properties that have 4 heaters so there is a way to do it... Just need to be sure the design is OK because it will be me that signs it off.

 

[Wilko]

Hi Tony - a detailed look at them will allow further load trimming, I reckon. Light circuits - convert to all LED so maybe 1A. What cooker model is it, if I may ask? If I've understood correctly there's only one RCD, so I'd probably look at a 2nd and split the load.

 

[TonyJohnson]

Hi Wilko,
Yes the cooker is quite old and is 11.8kw. I have advised the customer to get rid.
At present, yes one 80A RCD, so i would have put the wall heaters on there own RCD... I think the lamps are energy efficient so more like 3Amps. Plus ive quoted 26A on the ring. There are only 10 sockets in the house so its probably only running at about 10A tops... So with that we have shaved the load from estimate 115A to 110A Plus a smaller cooker would get us to around 70Amps and that is xmas day full load.

 

[Pete999]

W

Thanks Mhar but its a new elecy shower. Whats bothering me is i have done a few jobs in domestic properties that have 4 heaters so there is a way to do it... Just need to be sure the design is OK because it will be me that signs it off.

ho was the designer of the installation?

 

[TonyJohnson]

Why?

 

[Pete999]

Why?

Bicause the certificate will nee the designers name on it

 

[Des 56]

If you are at the point of thinking about a smaller cooker etc,it may be wise rather than chopping equipment into smaller chunks,use priority relays to perhaps example disconnect the heaters when the shower is running

 

[telectrix]

just add heaters at will till the DNO fuse blows. then you know you've gon a bit too far and take a couple back for a refund.

 

[dmxtothemax]

With the existing loads, then one would be the most,
But if you are not using the two biggest loads,
then you could add three more.
You would have to add circuits for them.

 

[Gavin John Hyde]

With the lot20. Changes pretty much all electric heaters must now have thermostats. A lot of heaters that last year could be wall mounted now cant. Even though the model is exactly the same. It seems bit daft when you think about it. The dimplex website has a good tool where you can enter room sizes. Windows etc to give a indication of the kw rating of the heaters that will be required.

 

[Gavin John Hyde]

With the lot20. Changes pretty much all electric heaters must now have thermostats. A lot of heaters that last year could be wall mounted now cant. Even though the model is exactly the same. It seems bit daft when you think about it. The dimplex website has a good tool where you can enter room sizes. Windows etc to give a indication of the kw rating of the heaters that will be required.

 

[elsparko]

storage heaters are on through the night, when there is little else running

if you plan on having 24hour supply heaters you may run into issues