3 phase connection DNO issues

[Canski]

The design is basically done , 9kw Daikin heat pump with UFH on the ground floor and rads on the first.  The EV chargers are a planning requirement and I don’t have / intend to have an EV in the near future but would like to have the option to plug in if I change my mind. 

[ProDave]

9kW heat pump will probably consume 3 or 4kW of electricity.

 

7kW charger

 

That would all run from my 12kW supply allowing for diversity, ASHP mostly used in daytime, charger mostly used overnight.

 

Especially if you are not even using the charger.  To be asking for a 100kW supply for that is madness.  A typical domestic supply is about 20 kW.

 

You need to get to speak to someone.  When I was enquiring they offered me the 12kW supply at a cheap price, I think they offered that, hoping I would say no, I need more in which case I would then be helping to fund a network upgrade somewhere.  But my supply has been entirely adequate.

[Canski]

4 hours ago, ProDave said:

9kW heat pump will probably consume 3 or 4kW of electricity.

 

7kW charger

 

That would all run from my 12kW supply allowing for diversity, ASHP mostly used in daytime, charger mostly used overnight.

 

Especially if you are not even using the charger.  To be asking for a 100kW supply for that is madness.  A typical domestic supply is about 20 kW.

 

You need to get to speak to someone.  When I was enquiring they offered me the 12kW supply at a cheap price, I think they offered that, hoping I would say no, I need more in which case I would then be helping to fund a network upgrade somewhere.  But my supply has been entirely adequate.

Thanks Dave. 
 

So I think I will go back to them and ask for a quote for 30KVA 3 phase per house and I should be covered or should I go in lower ?
 

I didn’t mention (and not sure if it is relevant) but the supply is on the other side of a quiet road about 9 m from my boundary and then each supply would need to go about 15 m to the meter box on the houses. The water will need to cross at roughly the same point. Then I would need to try and get them to co ordinate the works to prevent disruption to the road users. This will no doubt be difficult. 

[TonyT]

Do you need 3 phase?

 

[Canski]

4 minutes ago, TonyT said:

Do you need 3 phase?

 

I don’t know is my simple answer to this. I’m not an electrician. The site is an infill site on a 5 year old housing estate and I believe that all the houses are on 3 phase. 

 

[TonyT]

Most houses are single phase so ask for a single phase quote 18 kVA

 

thats approx 80 amps single phase.

[Mr Blobby]

On 04/06/2023 at 17:11, Canski said:

I don’t know is my simple answer to this. I’m not an electrician. The site is an infill site on a 5 year old housing estate and I believe that all the houses are on 3 phase. 

 

 

If 3-phase is close to the cost of a single phase connection, then get 3-phase, just to future proof extra car charging, or whatever else.  Three phase will make it easier to have more PV on the roof as well.

[Canski]

I received a reply from the complaints dept. I am holding my breath .....

 

'Just to provide an update on this, as Design Manager, I am reviewing the project and the quotes we managed to obtain. I am confident that we will be able to reduce this cost as it is significantly higher than I would expect and have queried this. That we have multiple quotes from different suppliers all in the same ballpark suggests there may be something about the works significantly inflating the cost.

 

Jack had initially requested this to be challenged and flagged the significant increase to me prior to issue. We were keen to get the cost that we had managed to obtain to you as soon as we could with an intent to hopefully offer a reduction soon thereafter.

 

I have also spoken to and challenged the providers regarding these costs to understand what is driving them and to minimise their scope (i.e. on site trenching, ducting, meter box etc provided by yourself). I’m chasing for a response this week but wanted to reassure you that we are doing what we can to reduce the cost.

 

Whenever we quote, we send the work to contractor’s who have been willing to quote in the past. We are also frequently going to other suitably accredited companies to see if they are willing to quote in order to get the best costs.

 

In relation to whether a smaller capacity would save cost, I can confirm that the works involved would not change. There is an uplift going from single phase to three phase due to extra materials and jointing works involved. 

 

Very few properties require a three-phase connection as a single phase connection provides 23kW of capacity which is sufficient for all the technology including in a typical house. Occasionally a customer requests a larger supply for a high capacity EV charger though this is not usually warranted unless the customer needs charging speeds greater than a full charge overnight.

 

Regarding the timescales, we are at the behest of these contractor’s to turn around their costs. We are exploring different avenues to address this (such as bringing in internal resource, standardised costing, working with our group companies) as well as our difficulties with application volume due to a 10x increase in generation applications relating to the energy crisis. We have significantly increased the head count of the team but are still struggling to meet the timescales we wish to achieve whilst trying to deal with applications fairly.'

[Canski]

On 02/06/2023 at 15:58, Canski said:

So the quotes have finally come back to me from the DNO I am absolutely flabbergasted. 

 

Last year the quote for 2 x 3 phase was £4200 now it is £14017

 

Last year the quote for 2 x single phase was £ 2012 now it is £12017

 

Last year the quote for 2 x  gas was £1770 now it is £12518

 

Is there anything that I can do ? 

 

It’s getting better. New quote in after contacting the complaints dept. £10450 for 2 Nr 3P 100A self dig on my property. I still can’t bring myself to cartwheel round the site.