UK Maximum demand

[Dacino]

Hi All I am doing my assignment and one of the tasks is to create a fuse board schedule showing circuit breaker ratings any assumptions must be stated with reasoning given. using these circuits calculate the maximum demand of the installation
Can someone tell me if it is right

So without making it long I did my calculations and got this high number 119.18Amp

This is the circuits
Shower 9.5kw. 45amp cb

Cooker 14.0kw 30amp cb

Ring 1 32amp 32amp cb

Ring 2 32amp 32amp cb

Immersion heater 3kw

Lighting 9x100w 6amp cb

 

[SparkyChick]

SparkyNinja ran a webinar recently about this.

View: https://www.youtube.com/watch?v=Y44YaTeo7mM

 

[Wilko]

Hi - just for fun, my version from Appendix A of the OSG at 240V :

Lights 66% - 0.6kW or 2.5A
Immersion 100% - 3kW or 12.5A
Cooker calc - 5.9kW or 24.5A
Shower 100% - 9.5kW or 39.6A
Outlets est - 3.8kW or 15.8A (this is estimated as 100% of a 3kW kettle and 40% of 2kW for every other thing)

Total - 22.8kW or 94.9A max demand.

 

[Ian1981]

Highest load plus 40% of the remainder is my method.
There’s no definitive answer, just common sense and experience.

 

[Dacino]

Highest load plus 40% of the remainder is my method.
There’s no definitive answer, just common sense and experience.

Hi my confusion is the osg says no diversity allowed for showers and immersion heaters so how can I take 40% of them if no diversity is allowed the osg doesn't really help much lol

 

[Ian1981]

Hi my confusion is the osg says no diversity allowed for showers and immersion heaters so how can I take 40% of them if no diversity is allowed the osg doesn't really help much lol

Take your highest load say an electric shower, then add your other loads together, the other loads added take 40% of the total then add it to your shower.

 

[Dacino]

Hi - just for fun, my version from Appendix A of the OSG at 240V :

Lights 66% - 0.6kW or 2.5A
Immersion 100% - 3kW or 12.5A
Cooker calc - 5.9kW or 24.5A
Shower 100% - 9.5kW or 39.6A
Outlets est - 3.8kW or 15.8A (this is estimated as 100% of a 3kW kettle and 40% of 2kW for every other thing)

Total - 22.8kW or 94.9A max demand.

I done it again and got around 76A after I did 100% +40%of the remainder just a little confusing with the shower and cooker I know the cooker is the highest circuit so I take 100% fl +40% of the rest of the circuits now my problem how do I take 40% of the shower and immersion heater as the osg says no diversity allowed
[automerge]1588101784[/automerge]

SparkyNinja ran a webinar recently about this.

View: https://www.youtube.com/watch?v=Y44YaTeo7mM

Thanks for the vid it helped me just the 40% remainder is what's bothering me now

 

[Dacino]

Take your highest load say an electric shower, then add your other loads together, the other loads added take 40% of the total then add it to your shower.

Okay thank you for that

 

[telectrix]

applying diversity to cooker, it will never be more than 25A so the shower is the heaviest load.

 

[Ed Evans]

Hi All I am doing my assignment and one of the tasks is to create a fuse board schedule showing circuit breaker ratings any assumptions must be stated with reasoning given. using these circuits calculate the maximum demand of the installation
Can someone tell me if it is right

So without making it long I did my calculations and got this high number 119.18Amp

This is the circuits
Shower 9.5kw. 45amp cb

Cooker 14.0kw 30amp cb

Ring 1 32amp 32amp cb

Ring 2 32amp 32amp cb

Immersion heater 3kw

Lighting 9x100w 6amp cb

The on site guide will give you the answer. You are over the top without applying diversity. Appendix A page 122.