Maximum demand

[tom262]

Help!!! I've been asked to work out the maximum demand for a new property for the DNO, I believe I have worked it out correctly applying diversity (something I've hardly looked at since college) but it seems abit high.

there will be 12 potential circuits.
1. 32amp cooker
2. 32 amp hob
3. 32 amp ring
4. 32 amp ring
5. 16 amp radial (sockets)
6. 6 amp lighting circuit (20 10w led downlight and 5 5amp sockets)
7. 6 amp lighting circuit (20 10w led downlight and 2 58w twin floersent)
8. 6 amp lights circuit (5 10w led downlight, 3 extractor fans, 10 outside lights 40w each)
9. 3kw immersion heater
10. 20-32 amp air source heat pump (unsure on size yet)
11.solar pv
12. 40 amp shower circuit (may not be used)

After applying what I believe to be the correct diversity I have a total maximum demand over 100amp this seems abit high??
thabks in advance Tom

 

[trev]

So what is your diversified load by circuit and what method have you used?

 

[the pict]

add up the MCBs and then x 0.4. unless the law changed while I was having a kip, yeah I know theres better ways but he is after a ball park right?

 

[trev]

So using the /4 method I get 50-60A
I'd still like to know what the OP gets and how.

 

[golfpaul]

I dont think itd be anywhere near 100a

 

[driverman]

Help!!! I've been asked to work out the maximum demand for a new property for the DNO, I believe I have worked it out correctly applying diversity (something I've hardly looked at since college) but it seems abit high.

there will be 12 potential circuits.
1. 32amp cooker
2. 32 amp hob
3. 32 amp ring
4. 32 amp ring
5. 16 amp radial (sockets)
6. 6 amp lighting circuit (20 10w led downlight and 5 5amp sockets)
7. 6 amp lighting circuit (20 10w led downlight and 2 58w twin floersent)
8. 6 amp lights circuit (5 10w led downlight, 3 extractor fans, 10 outside lights 40w each)
9. 3kw immersion heater
10. 20-32 amp air source heat pump (unsure on size yet)
11.solar pv
12. 40 amp shower circuit (may not be used)

After applying what I believe to be the correct diversity I have a total maximum demand over 100amp this seems abit high??
thabks in advance Tom

How is the property being heated? If Gas, possibly no need for Imm /Htr and or elec shower.
OPPS >>>> ASHP

 

[trev]

I dont think itd be anywhere near 100a

It won't be

 

[tom262]

How is the property being heated? If Gas, possibly no need for Imm /Htr and or elec shower.
OPPS >>>> ASHP

Air source hear pump,
'the cooker and hob I've done, 10A +30% for each
the rings as 32 plus 16 for the total of the two
the immersion plus the radial 16A for each
the lighting as 66% of each added together





unsure re on the PV and heat pump.

 

[trev]

Use the /4 rule mate.

 

[edrobbo8]

The PV is likely to be 4kw, unless it is a commercial property. Can't say re heat pump, could well be 6 or 8kw!

 

[davesparks]

The PV shouldn't be anything should it? That is after all the whole point isn't it?

 

[richy3333]

The PV shouldn't be anything should it? That is after all the whole point isn't it?

Does he mean solar water heating? The ones I've fitted take little to run?

 

[davesparks]

I think he would have said hot water of he meant it, what he said was PV,

 

[shanky887614]

Does he mean solar water heating? The ones I've fitted take little to run?

your thinking solar thermal

pv is photovoltaic, different tech.

solar thermal has a coil that goes to water tank to heat it

 

[Engineer54]

add up the MCBs and then x 0.4. unless the law changed while I was having a kip, yeah I know theres better ways but he is after a ball park right?

Really?? If you know of a better method let me in on the know!! lol!!

 

[the pict]

Sorry poor grammar E 54 I should have said OTHER ways

 

[telectrix]

better way..... you want DNO to fit a 100A fuse, so you tell them your MD is 90A. ssimplesss.

 

[Engineer54]

better way..... you want DNO to fit a 100A fuse, so you tell them your MD is 90A. ssimplesss.

Let's hope the Ze value is sufficiently low enough in order for a 100A BS88 fuse to operate in a timely manner!! lol!!

The DNO will want that 90A converted to a KVA value too...