UKPN unreasonable charge for 3 phase upgrade, but single phase upgrade free?

[NCXo82ike]

We're in a 1905 mid-terrace with the original supply cable from the street. With an ASHP, EV charger, 1 or two inverters and batteries, induction hob and 2x ovens going in, we needed to upgrade from 60A to 100A. Our supply cable was insufficient for 100A so we're booked in for a single phase supply upgrade which would be completely free.

 

We'll make use of time of use tariff. We'd benefit from a 22kW car charger. Doing shift work I have abnormal consumption schedules so our diversity doesn't reliably drop the total load much. As a result we could easily hit 35KVA and up to 53KVA. We can make do without 3 phase, but we'd definitely benefit from it. 

 

I understand Western Power networks install 3 phase by default if a supply upgrade is required. So I contacted our DNO UKPN to enquire about 3 phase supply. They tell me a 3 phase upgrade would make all works chargeable, estimated at £6700 (inc. VAT) excluding digging on our property.

£370 of that is the 3 phase cable and ducting, and the remaining £6300 is the labour (i.e. digging the pavement 3m from the house on our side of the road and making the connection, most of which would presumably be identical to the single phase work). That's prohibitive.

 

I wasn't expecting to get it as good as under Western Power , but I'd really hoped I could pay just the marginal cost of the 3 phase equipment and connection work- it feels absurd to have to pay for the digging.

 

Are there any strategy documents or consumer rights I can quote to try and just pay that marginal cost? Any advice greatly appreciated.

[nod]

A quick search on google says 3-15k

Yours could be worse 

[NCXo82ike]

48 minutes ago, nod said:

A quick search on google says 3-15k

Yours could be worse 

Agreed, could be worse, but I'm not quibbling with the cost of the work

 

Instead that they will be doing the vast majority of the work anyway, and for free given that we require a supply upgrade. But asking for three phase, why can't I pay a fair rate for the extra material and the labour above that.

 

It's like winning a free holiday, asking to pay to add inclusive drinks, and being told if you do you have to pay for the whole holiday. 

Except that I've not won a free holiday, it is policy to provide the benefit (I realise probably from everyone's standing charges, and am grateful for that).

Edited June 18 by NCXo82ike

[Roger440]

Welcome to my world! Logic and reason don't really come into it. Any opportunity to get the customer to pay for the infrastructure seems to be fair game. 

 

My quote was more than twice as much and it's from a pole that's 50ft from my building in my own field. 

 

Trying to reason with them, so far, has get me nowhere. 

 

I'm interested that they agreed to do a free upgrade to 100 amp though. I could live with that, as like you, mines a 60 amp supply.

 

How did you confirm it would be free?

[Temp]

I thought only fuse upgrades to 80 or 100A were free? 

[NCXo82ike]

2 hours ago, Roger440 said:

Welcome to my world! Logic and reason don't really come into it. Any opportunity to get the customer to pay for the infrastructure seems to be fair game. 

 

My quote was more than twice as much and it's from a pole that's 50ft from my building in my own field. 

 

Trying to reason with them, so far, has get me nowhere. 

 

I'm interested that they agreed to do a free upgrade to 100 amp though. I could live with that, as like you, mines a 60 amp supply.

 

How did you confirm it would be free?

After I applied for the upgrade, their crew came round to look at the supply and decided it was insufficient for 100A. Apparently they'll often replace the fuse at that first visit if it's all suitable. 

Then they booked it in as requiring a supply upgrade, which the crew, and then the team on the phone in a follow-up call, told me was non-chargeable. 

Next step is a surveyor comes out to plan the supply upgrade, to include closing the pavement, closing the road if needed (not in our case).

 

I have another surveyor coming to look at the property to quote for a plan a three phase upgrade. Presumably doing exactly the same task?

[NCXo82ike]

1 hour ago, Temp said:

I thought only fuse upgrades to 80 or 100A were free? 

I've been told if the incoming supply is insufficient for the uprated fuse, the supply upgrade is free. But if you ask for a new service, or moving the meter, that counts as chargeable (presumably seen as discretionary).

 

Edited June 18 by NCXo82ike

[Roger440]

Thanks for the info. Upgrading the existing supply (and installing a gen set) is my back up option.

 

Hopefully it's just a fuse change. Though the meter says 40amp max!

[Roger440]

On 18/06/2025 at 23:04, NCXo82ike said:

I've been told if the incoming supply is insufficient for the uprated fuse, the supply upgrade is free. But if you ask for a new service, or moving the meter, that counts as chargeable (presumably seen as discretionary).

 

 

Can you confirm that you were offered 100A please?

 

They will give me 80, but not 100. They said:" National Grid Electricity Distribution (NGED) downgraded the size of domestic connections some years ago."

 

Which i do in fact recall.

 

If you were offered 100A, can you advise who you are dealing with. Im dealing with National Grid (ex Western Power)

 

Its also not free for me, but not enough to get excited about. It just all appears wildly inconsistent.

 

 

 

[garrymartin]

National Grid can provide 100A on a single-phase in some circumstances, but 80A is standard. There are notes somewhere that an 80A fuse can cope with a 100A load for 4 hours, so they don't generally do 100A on a single-phase, but would look to do 60A on three-phase instead where possible.

 

Lots of NG documents refer to this including SD5A_6 and SD5G_5Part 1 (where the images below come from).

 

What are your specific requirements for 100A? Do they meet the conditions specified in those documents and in SD5D?

 

 

 

[Nickfromwales]

11 hours ago, Roger440 said:

They will give me 80, but not 100

If you don't average higher than the 80, and peak at 100/110, the HRC fuses will just run close to molten and cope with peak demand. It's only if you know you will have sustained 3x100a consumption, which is huge, does this become a problem.

 

I expect the 3x 80a would be more than ample for most things?

 

Welding sets prob worst, and shunt resistance from compressors etc will cause spikes, but then settle down when constant. Welding is in sporadic bursts so again maybe not such a problem.

[Roger440]

12 hours ago, garrymartin said:

National Grid can provide 100A on a single-phase in some circumstances, but 80A is standard. There are notes somewhere that an 80A fuse can cope with a 100A load for 4 hours, so they don't generally do 100A on a single-phase, but would look to do 60A on three-phase instead where possible.

 

Lots of NG documents refer to this including SD5A_6 and SD5G_5Part 1 (where the images below come from).

 

What are your specific requirements for 100A? Do they meet the conditions specified in those documents and in SD5D?

 

 

 

 

As per my thoughts elsewhere, i wanted a 3 phase supply for my workshop as i have some three phase equipment, and ideally, need a bigger compressor, which would be better three phase. Probably 7 to 10kw.

 

However, their position on this is i have to pay for all the network re-inforcement unless there were three houses off the same transformer. But theres only 2.

 

Theres simply no way im going to pay that much for a connection from a pole in my own field. Whilst im still debating this with them, i need to look at other options.

 

Realistically, i have 2. Install a genset (with batteries), or upgrade the existing 240v supply from the existing 60 amp one to 100amp. I "might" get away with 80amp. but i might have to apply some selector switch so i cant run the compressor at the same time as other loads. The house has an electric shower and eloectric cooker, both on 30amp breakers before you even consider the workshop.

 

With regard to the criteria you refer to (thanks for that) its a bit grey as its the workshop that tips it over. Its a workshop at home, for my own use, so "domestic" in nature, but obviously, has electrical demands beyond what most would consider "normal". So, i guess do NOT fall within the requirements. Would an EV charger pull  it in to the requirements?

 

Where are you finding these documents? Ive not found them.

 

 

 

[Roger440]

2 hours ago, Nickfromwales said:

If you don't average higher than the 80, and peak at 100/110, the HRC fuses will just run close to molten and cope with peak demand. It's only if you know you will have sustained 3x100a consumption, which is huge, does this become a problem.

 

I expect the 3x 80a would be more than ample for most things?

 

Welding sets prob worst, and shunt resistance from compressors etc will cause spikes, but then settle down when constant. Welding is in sporadic bursts so again maybe not such a problem.

3 x 80a would be brilliant. Except it makes no economic sense at all. 

 

Its like filling your car up at the petrol station, and them asking for £500 for the pump you used to fill up.

[Nickfromwales]

25 minutes ago, Roger440 said:

The house has an electric shower and electric cooker,

LPG for cooking and oil > DHW for a mixer shower?

 

23 minutes ago, Roger440 said:

3 x 80a would be brilliant. Except it makes no economic sense at all. 

Ah, so you're the other end of the scale, and have very minimal 3ph requirements then?

[JohnMo]

On 18/06/2025 at 17:58, NCXo82ike said:

ASHP, EV charger, 1 or two inverters and batteries, induction hob and 2x ovens going in

So most of the time house battery will be supplying during day. The only big users are battery charging at night for house and car, and during winter heat pump.

 

House battery charger isn't going to pull anymore than about 6kW, 2kW for heat pump.

 

80A x 230v, is approx 18.5kW. That gives you nearly 10kW for car charging. 7 hrs at 10kW is 70kWh or around 280 miles per day. So reality is you stack charge several cars per night.

 

Do you really need more than that? All this 3 phase for residential homes is utter nonsense.

Edited 19 hours ago by JohnMo

[Roger440]

36 minutes ago, Nickfromwales said:

LPG for cooking and oil > DHW for a mixer shower?

 

Ah, so you're the other end of the scale, and have very minimal 3ph requirements then?

Dont really want LPG. Longer term, yes could move to oil for the shower.

 

The compressor would be the primary load for three phase, with occasional, lower load devices as well.

[garrymartin]

3 hours ago, Roger440 said:

Where are you finding these documents? Ive not found them.

https://www.nationalgrid.co.uk/documents/tech-info/design-standards/low-voltage?page=4

 

[Roger440]

54 minutes ago, garrymartin said:

https://www.nationalgrid.co.uk/documents/tech-info/design-standards/low-voltage?page=4

 

 

Thanks, most useful

 

The below seems to be they key point. ie, 100A may be acceptable....................

 

 

 

Depending on if one can take workshop loads into account, depends which side of the line you fall. With an EV charger, a heat pump, cooker, shower, plus my workshopn inc compressor, one could easily calculate accordingly for a 100A supply. But i dont currently have all those thngs. Because i dont have a supply.

 

I shall have to try and see if i can make progress on the single phase side of things.

 

All that said, its probably acedemic as the supply cable almost certainly isnt big enough if we take the below into account. The supply id suggest is no more than 10mm2 cable.

 

 

Its all rather complicated for the layman to challenge.