A summation supply.

[flyingspark]

Hello,

I am looking for help and advise with a summation supply arrangement.-

I have been asked to quote to install a supply to a shed (yes it is that time of year again!), where the intended additional load is (60-70A).

Combine that (60-70A) with the existing demand of the house including diversity of 105A, it would seem (on paper at least) to much for a single phase supply. I havent checked the main fuse, but it says 60A on ceramic holder.

Ive been considering suggesting to the customer to have 3 phase installed, but then it opens up problems with balancing the load between phases etc etc, and all the expense.

Would it be reasonable in this case to suggest a summation supply? I am asuming the supply company can (at cost) install a second fuse head from the same single phase supply.

Has anyone here done this or had to have this done?

Any idea of costs?

All help or advise welcome.

Many thanks.

 

[a1]

Would it be reasonable in this case to suggest a summation supply? I am asuming the supply company can (at cost) install a second fuse head from the same single phase supply.

Can't see why not. It is no different from when the DNO loop into a next door property from yours.

Cost? A few thousand, knowing the DNOs.

Over what disance are we talking here? Is all the cable route on private land? (As long as it doesn't cross public highway - you can do all the digging, laying of duction, and warning tape, and to place the nylon draw rope through for the DNO, and it will be a darn site cheaper).

Naturally, Doing it that way, you will have two seperate supplies and two seperate bills. DNO will not do it, until you have arranged a supplier (REC) and they have installed their Meter etc. (At least, that is what it is like down here anyway. DNO is Western Power and REC is Swalec aka SSE.

 

[ianmacd]

Can't see why not. It is no different from when the DNO loop into a next door property from yours.

That will depend on if the existing cable is able to cope with the extra load. They may want to run a new cable in.

 

[flyingspark]

Thanks for responses so far Admin & Ianmacd.

The distance for the second supply would be the same as the first. Thats because I would only want them to go from street, along side existing supply to next/near the current service fuse under the stairs.

The customer has already dug a deep enough 30m long trench from house up to his shed in back garden. So, he wants me to run 2 core SWA 16mm csa in the trench, terminate etc, so alot of the ground work has been done.

 

[netblindpaul]

flying,

Try to get some load history on the house first.

Clamp the tails for a day at least and put a mempry clamp on it.

Otherwise try to simulate a realistic full load situation.

Then thing seriously about diversity on the supply.

DNO's will use about 0.4xflc for a domestic.

What is going into the shed to take 60-70A of load continuously?

Seems a lot even for Admin's shed!

Have a think and post some more and we can try to build up the picture with you.

Paul

 

[Evans Electric]

I've known the Network fit a second 100A fuse to a SP supply for electric heating.

Why do you want 60-70 amp supply to a shed ? If that were round here it would be for growing canabis !!! Except that it would'nt be metered.

Where did you get the phrase " Summation supply" from ? New one on me. :C

 

[batty]

Get DNO to upgrade supply to 100 amp you would be hard pushed to blow that.

 

[flyingspark]

Big thanks to everyone for all the responses so far.

Am going to follow Netblindpauls advice and plant a clamp meter set to record max. value over the weekend.

What is he going to use his shed for? -

He tells me he wants to install a sauna which is 6kW, he also wants to run 2 x Burco type things which are used for brewing beer at 2.7kW each. Some general use sockets for freezer. Lighting.

Adds up to (approx. before diversity) to be 70A. With diversity 55A, add that to house demand (diversity included) of 105A = 160A, surley a 100A cut out would not hold if everything switched on for more than 30mins?

I will post results of weekend clamp results, and hopefully it wont be as high as expected.

Thanks again, and have a good weekend to all.

 

[batty]

I would think it all depends on what he wants to spend. How often is brewing going to be done, is he likely to want to brew while sauna is on, is he likely to want to spend

 

[flyingspark]

Ok, so I placed my clamp meter in position on the Friday eve, collected on Sunday eve, so monitored for 48 hours over a weekend when everyone was home. Max (peak) current draw was 24A.

So, looks like it can go ahead, Batty - told him no brewing whilst having a sauna!

Many thanks to all who have helped with this.

 

[m4tty]

I would think it all depends on what he wants to spend. How often is brewing going to be done, is he likely to want to brew while sauna is on, is he likely to want to spend

 

[batty]

Happy days.

 

[kme]

I've known the Network fit a second 100A fuse to a SP supply for electric heating. Why do you want 60-70 amp supply to a shed ? If that were round here it would be for growing canabis !!! Except that it would'nt be metered.

Where did you get the phrase " Summation supply" from ? New one on me. :C

It is correct, Deke. I`ve had one fitted to a 3 storey house, when we converted the basement into a self-contained property. Leccy showers (2 in the main house, 1 in basement conv, all at 10Kw; electric UFH (solid 5KW load) and full kitchen - all electric.

A summation supply is just a second hed from the same phase as the first; usually spliced from the trunk line. DNO (I think) charged the customer about