What is maximum demand and diversity

[susantha]

any explanations on this title it will help me out with my exams

 

[a1]

Hello,

There a few threads here, explaining.

http://www.talk.electricianforum.co.uk/search.php?searchid=537640

I am awaiting a reply on your 205 & 206 thread too.

Best Wishes,

Admin.

 

[ADS]

Hi,

Maximum demand is the maximum load likely to be applied to a

circuit or installation.

To calculate this figure you add up the total loads and apply an

allowance (diversity).

Diversity is an allowance that is made to some loads (eg. a cooker)

taking into account that every ring/oven/grill is not likely to be switched

on at the same time for any substantial length of time, so you reduce

your max demand figure by a certain percentage.

Hope that helps

 

[SPECIAL LOCATION]

Just to add a bit more to what ADS said...

the cooker illustration also applies to ALL circuits and ALL outlets and ALL accessories on any installation..

Basic rule:

Every item of electrical equipment is NOT switched on running full power for the whole of the time.

The actual full load demand will peak and trough at various times though the day, the week and the year.

Diversity is the concept of estimating a probable demand of a circuit / installation.

BUT there is NO hard and fast rule, 'one size fits all' calculation that is automatically correct for every installation, It really is a case of the designing / installing electrician has to make judgments based upon their own knowledge and experience of the installation.

Another example may be a Dishwasher, Washing Machine and Tumble drier all on the same ring circuit, say each was rated @ 2300watts, (10amps)

IF they are all running simultaneously there is a possible max demand of 30amps from these items..

BUT real world because dishwashers & washing machines have their current drawn change during the various stages of the wash cycle...

It is quite probably that even with all three on together the actual max power may still only be somewhere between 15amps & 20amps!

On site guide Pages 95 to 97 will give you some guidance.