UK New electric supply connection

[wwilts]

New 46kVA electric supply to new backland dwelling (37m from footpath). Mains cable runs along the footpath at the road access.
Which option would you choose and why?

Option 1

Meter box near footpath. Own fuse and armoured cable (>30m distance) underground to new dwelling.

Option 2

Meter box 25 m from footpath. Own fuse and armoured cable (<15m distance) underground to new dwelling.

 

[wwilts]

I've been involved with builds in the middle of nowhere on many occasions, and on some, I've got over the problem of a site supply by getting the builders to build just a small triangular section of the outer house wall to build the meter box into. I've then fixed my board (used on many sites) with an IP65 small RCD protected consumer unit and two IP55 double switch sockets on it, to the reverse side of the wall section, in what eventually will be the cavity.

Builder will need electricity before the building comes out of the ground. And DNO provides only 25 m of their own stuff within the quoted price. Suggestion was to provide external meter box/kiosk to receive DNO supply, & eventually run own SWA to dwelling. Then DNO does not need to provide another quote for covering the <15m distance remaining from kiosk to dwelling.

 

[Mikegh]

Won't 30m of swa give you less to play with on voltage drop and fault loop impedances in the building itself

 

[plugsandsparks]

BTW 100A Supply off three phase is around 70KVA so you can fill your boots with EV, lol
On a serious note, be aware of what charging the individual cars will take before blindly connecting 4 EVs and going to bed..??

 

[wwilts]

How about this approach:

Single phase supply to dwelling.
3 phase supply for EV charging only (as and when that is installed).

Workable?

 

[brianmoooore]

Won't 30m of swa give you less to play with on voltage drop and fault loop impedances in the building itself

It'll be the same voltage drop whether it's a DNO cable or a private one. The difference is that you won't have to take it into your calculations if it's DNO. Will help with loop impedance if it's TNC-S, not so for TNS

 

[Gavin John Hyde]

Just because you have a.22kw ev charger doesnt mean the car will charge at that rate. A lot wont charge above 7kw.
As.for DC rapid charging why have two 22kw if fitting one of these?
I installed.a.dc.rapid charger for a guy in Bath. Had to use a lifting machine to position it! Weighed nearly 100kg also had a.22 kw Andersen for visitors etc
He had a small fleet of cars for family, staff and security so needed rapid charging. When people.got back cars.were charged and cleaned.

 

[wwilts]

Just because you have a.22kw ev charger doesnt mean the car will charge at that rate. A lot wont charge above 7kw.

True. But in due course most cars might allow faster charging.
The 3 phase was obtained just to future proof the new build to some extent.

Does the distance from the 3 phase distribution board to the EV chargers matter much? For example, 3 m vs 20 m?

 

[Mikegh]

True. But in due course most cars might allow faster charging.
The 3 phase was obtained just to future proof the new build to some extent.

Does the distance from the 3 phase distribution board to the EV chargers matter much? For example, 3 m vs 20 m?

Costs more money ,.you.have to factor in the distance

About it I'd say

 

[Gavin John Hyde]

True. But in due course most cars might allow faster charging.
The 3 phase was obtained just to future proof the new build to some extent.

Does the distance from the 3 phase distribution board to the EV chargers matter much? For example, 3 m vs 20 m?

Yes, that extra 17M of cable will cost more anything from £50-£100 depending on cable, where purchased etc then you have cable fixings, larger glands. labour costs as trying to work with some large cables can be tiring and like wrestling an anaconda.
Then you have to account for voltage drop, 20M is a small run but when you are fitting a charger at a property and you have a cable run of around 40M then it becomes a much bigger issue, careful circuit design and calculation can mean you use a smaller cable and thus save money/materials. I had to get the groundworkers to run 10mm SWA 3 core recently for a garage install and whilst only supplying a single 7kw charger, some sockets and led strip lights, had to increase the cable size from 6mm to allow for the MD and voltage drop as the cable run was a right zig zag affair through rocky ground and around other services.