max demand

[scott 123]

went to domestic job today where max demand was 236A (around 175A after diversity) main fuse is 100A so demand seems high to me...just wondered when you design what demand do you go to

 

[Silly Sausage]

Original question was how much do u go to

To the size of the incoming fuse!

 

[scott 123]

Garage and boiler thats the cicuit the installer installed

 

[scott 123]

Not that helpful

 

[Andy78]

Not that helpful

Neither is your info. What's in the garage that is drawing 50A ?

 

[scott 123]

Original question was how much do u go to

To the size of the incoming fuse!

Lots of boards ive seen are over incoming fuse

 

[Andy78]

Which of these do you think is closest to the actual current draw of an installaton ?

• the ratings of all the mcbs added together
• the ratings of all the mcbs added together with diversity applied by the OSG method
• the ratings of all the mcbs added together multiplied by the rule of thumb figure of 0.4
• the rated total of all connected loads

Your clamp meter knows the answer...

 

[scott 123]

50 amp supply from main to board to board in garage with 32 a ring ...6a lights...6a outside lights .....16a hot tub.....20a outside socket ...I know it wont use any near but thats what the design is..I didnt design it I just interested in design opinions

 

[Silly Sausage]

Not that helpful

Neither is your info. What's in the garage that is drawing 50A ?

What Andy says, a list of MCB/circuit max ratings is vague to say the least!

 

[scott 123]

How do u clamp..at design stage..would b intersing to see that being done :O

 

[R G]

Anything nice growing in the garage?

Could be , just seen another thread where the storage heaters have got a real high , the op says the storage heaters are tripping !!!LOl..

 

[Silly Sausage]

Not that helpful

How do u clamp..at design stage..would b intersing to see that being done :O

You're at an existing installation, presumably with the cts you've listed, clamping it might just give you an idea of the actual demand.
Without knowing the full details of an installation, trying to do a design spec on an internet forum is nonsense.

 

[Andy78]

50 amp supply from main to board to board in garage with 32 a ring ...6a lights...6a outside lights .....16a hot tub.....20a outside socket ...I know it wont use any near but thats what the design is..I didnt design it I just interested in design opinions

So did the designer. Design includes diversity. How you choose to apply diversity depends on the way you were taught and your experience.....

 

[scott 123]

At last a sensible answer

 

[Silly Sausage]

Try it at home.
You can work it out in minutes from your statements or monitoring your meter for a week or so, you'll be amazed at low it is.
Unless you get HUGE bills all the time.


I average about 3 Amps max over about 18 hours a day.

 

[Plonker 3]

Here's a example for you

If a 32 amp radial had 2 single sockets on it, and another 32 amp radial has 12 single sockets on it which one is the bigger load?