Maximum demand greater than 100amp single phase ukpn

[Gus Potter]

Hilarious. Was talking to the spark about the upcoming IEE 19 regs and said I fancied arc fault protection.. until he said you have two fuse boards and.. then pointed out that I have been at doing my own house for longer than I "predicted"... and I may be best spending the money on other things.

 

I'l stick with diversity for now.. and upskill to selectivity next year.

 

On my office wall hangs a hand line drawing of Bradwell Nuclear Power Station which is a work of technical art, a Hemingway hat and my Teady bear from when I was about 4, one Teddy suffices as not of Royal descent.

 

I'm not sure what will be banned next!

 

 

 

 

[Carrerahill]

17 hours ago, Newbuildnewbie said:

Hi

 

We're building on a plot previously occupied by a bungalow which has a single phase supply with 100amp fuse 

 

We have an ashp (16kwh) and are asking UKPN for permission to install but our electrician is telling us that allowing for electric car point in the future etc that we could be looking at a maximum demand a little in excess of 100amps

 

Has anyone experienced this and know what UKPN will say? I'm guessing these calculations are made on an abundance of caution because ashp are supposed to be efficient etc so won't run at full whack and if we did have electric car point in future we would probably charge at night etc so I don't really want to pay to upgrade to three phase if not really necessary given the single phase supply already there currently. 

 

Any thoughts appreciated! 

Have a look on this forum for posts by me recently, I have written pages and pages and screeds of text on this and posted BS88 (your standard UK cut out fuse type) fusing curves showing what a 100A fuse will actually do at 100A (nothing). 

 

Search by my recent posts and I am sure you will be enlightened.

[Carrerahill]

 

We all like photos, I took this photo yesterday doing a site survey. These are 2 11kV 400A breakers which protect two transformers. Note the 11kV cable coming in on the right, dropping out the back at low level and going into the trench are the 2 outgoing 11kV cables going to 2 transformers. This is actually client owned as the point of connection from SPEN is 11kV - behind this wall is a 11kV ring main tap using a MEM ringmaster unit - basically a 11kV cable in from the grid, and back out, then a single cable into these two boys. 

 

You will note on the right hand breaker the load is shown as about 4.5 (x10 multiplier) - that is 45A at 11kV! Pretty serious!

 

This is what protects a 5 industrial units and 15 little modular offices.

 

 

 

 

[TonyT]

18 hours ago, Onoff said:

 

Beware the Christmas dinner effect!

 

It's all gone pc now with regard to overcurrent protective devices and say RCDs on the same circuit. Diversity between devices in that context is now know as selectivity 😂

discrimination is now selectivity.

can’t have discrimination now you know!

[Onoff]

20 hours ago, Onoff said:

 

Beware the Christmas dinner effect!

 

It's all gone pc now with regard to overcurrent protective devices and say RCDs on the same circuit. Diversity between devices in that context is now know as selectivity 😂

 

EDIT: With thanks to @TonyTfor making me realise my mistake. I got my diversity and discrimination mixed up. Diversity is diversity. As Tony said discrimination has now become selectivity. 

 

Just goes to show you can get near 100% on your 18th (which is just reading a book) and still know f*** all. 

 

In my defence I am drinking a lot of late...

[Nickfromwales]

On 16/03/2022 at 00:22, Gus Potter said:

But if you have say one of these electric Ferarris that do ultra rapid charging at some 400 amps

 

.....and you rock up and plug it in, turn around, and notice that next doors water feature has stopped working 🤣

Edited March 17, 2022 by Nickfromwales
typing with left, eating yogurt with right.

[Russell griffiths]

41 minutes ago, Nickfromwales said:

 

.....and you rock up and plug it in, turn around, and notice that next doors water feature has stopped working 🤣

 

42 minutes ago, Nickfromwales said:

dited 40 minutes ago by Nickfromwales
typing with left, eating yogurt with right.

Yogurt. Who you trying to kid tubby. 

[redtop]

If you don't apply diversity its very easy to say you need more than 100amps. Sparkles tend to apply diversity when calculating cable sizes, loads etc as a standard. Are you sure he is a sparky? Having said that, ashp, elec cooker and car charger and its very easy to exceed 100amps if you just add up the total loads

[PeterW]

14 minutes ago, redtop said:

Having said that, ashp, elec cooker and car charger and its very easy to exceed 100amps if you just add up the total loads

But you would have to be charging your car on a very cold day with the heat output set to 50°C whilst batch cooking a lot of boiling soup …. 
 

Diversity is there for a reason and this is also why Western Power are pushing 3Ph heads into new builds so you can put your car on one, ASHP on another and then leave the house on its own phase. 

[redtop]

23 minutes ago, PeterW said:

But you would have to be charging your car on a very cold day with the heat output set to 50°C whilst batch cooking a lot of boiling soup …. 
 

Diversity is there for a reason and this is also why Western Power are pushing 3Ph heads into new builds so you can put your car on one, ASHP on another and then leave the house on its own phase. 

And microwave on, few laptop chargers, kettle. But I agree, thats why we have diversity. I would 3 phase as well to future proof.

[Nickfromwales]

1 hour ago, Russell griffiths said:

 

Yogurt. Who you trying to kid tubby. 

Is this cyber bullying? 
 

Its “Mr Tubby” to you Bruce. 👌. 

[SteamyTea]

35 minutes ago, Nickfromwales said:

Its “Mr Tubby” to you Bruce

Tubbs is a lady.