Domestic three phase? advice

[Jay]

Hi

I have recently moved into a small newly renovated (inc electrics) cottage and noticed appliances going really slow. Kettle taking an age to boil, toaster taking a long time, hair clippers going slow... you get the picture.

UK power networks sent an engineer that changed the overhead power line. He monitored the voltage at the plug sockets with no load and was getting 216v. He advises to get an upgrade to three phase.

Move forward to the site survey. A new technician says Three phase is not required on such a small property and that UKPN will need to get a monitor installed temporarily to monitor the incoming voltage.

UKPN customer services are not having any of that and are insisting it does require a Three Phase upgrade going against the site survey technician.

It is worth noting the house only has electricity (no gas) including an electric combi-boiler. We have overhead power lines and we are the furthest house on the street from the supply.

Another technician is due out next week for another survey.

As you can probably tell I am no expert so any advice would be very welcome. Is three phase usual on a small domestic property?

Thanks.

 

[7029 dave]

I'd love to hear their logic behind this.

Yes, the single phase supply is going to be tapped off the 3 phase supply anyway,216v per phase, unless there is another supply cable run on the street, with hopefully higher voltage.(different tranny)

 

[PEG]

Hi,do you know what the voltage is,with some normal loads,including that electric combi on song?

 

[dmxtothemax]

it looks like a heavily loaded local electrical network,
or your at the end of a long line.
either way it's the network not the equipment.
Try reporting low voltage and request more capacity ?
(bigger local transformer).

 

[freddo]

I'd love to hear their logic behind this.

By insisting the OP needs to have a 3 phase supply would mean the OP would get the bill for the work instead of the current problem being corrected at the expense of UKPN.

 

[PEG]

Maybe,just maybe,the DNO is aware of this issue,but rectifying it,could involve multiple customers,and a large expenditure...but...a 3 phase connection,from a nearby sub-terra supply,would avoid this,and,because offering this for free,would flag the aforementioned problem,an invoice is obligatory...

Purely conjecture,and,obviously,this has never,ever,happened before...

 

[Percyprod]

Working for ENWL we used to regularly fit voltage recorders for this sort of problem. Leave it in for a week, check the voltage over this time, as it does vary according to the load and other factors. As said previously voltage to be between 216 and 253. Daft idea to think major upgrade to 3 phase required. If other properties on same supply suffering same problem we would check voltage at sub station, and adjust transformer tapping if required.

 

[Jay]

I have UKPN coming around for the second time this Thursday so will report back. I took few readings at a single socket at various times (that's the extent of my electrical ability) this weekend. I got the following:

11am everything off 224v
11.05am combi turned on 211v
17:00 with lights and combi on 214v

 

[Taylortwocities]

Interesting that combi+lights has higher voltage than what should be a lower load (combi on its own).

I guess the combi is a gas or oil device, ie not electric? If so, its load will be insignificant. You are better to test the voltage with a kettle, an electric oven and a couple of electric heaters switched on.

Your voltage test is looking at the voltage as it comes in your door. If you are on a long feed from the substation, which may be shared with other users, then the voltage drop will vary as your neighbours ramp up their consumption.

It will be interesting as to what UKPN have to say.

 

[Strima]

Local farmer probably has his grain dryers set too high!!!

 

[Percyprod]

It is quite unlikely that all 3 phases on the supply will be the same, different loads on each phase will affect them, as will time of day. That is why monitoring equipment is left in for a week, no good doing a test at only one time. It should also be tested at the incoming main fuse point, not at a socket.

 

[campo]

I think I saw a similar problem to this a few years back. It turned out to be ivy growing into the transformer.

 

[UNG]

I have UKPN coming around for the second time this Thursday so will report back. I took few readings at a single socket at various times (that's the extent of my electrical ability) this weekend. I got the following:

11am everything off 224v
11.05am combi turned on 211v
17:00 with lights and combi on 214v

Looking at the voltages at 224v you are only 6v under the nominal supply voltage of 230v turning the combi on drops the voltage by 13v which is quite significant but you don't give any details of the boiler or any other load. When checking the voltages it is a good idea to take load and no load readings as the 17:00 figure is a bit meaningless without having a similarly timed no load reference

I looked into electric boilers for a job a while ago and some of them would push any normal household supply well beyond it's capacity with loads of 15+KW.

Before making any comment about what UKPN are recommending it would need the OP to furnish a lot more info, I would suspect that the property and surrounding properties are on an old overhead supply that predates today's high electricity usage if the supply is feeding a number of properties similarly equipped with electric boilers then it is likely it will not capable of delivering what is needed without reinforcement
The problem the OP has is not unusual these days any will become a major issue if electric vehicles become the norm, I wonder how many installations exceed their original installed capacity.
Only last week I found a 60A cutout that was a bit worse for wear and had clearly been overloaded this was replaced by the DNO with a nice new 100A cut out, yes it gives the installation a bit more capacity but the supply cable is still the same old PILC it was before

My thoughts with the DNO suggestion of an upgrade to three phase would be how close is the three phase to the property and is the DNO trying to get some unsuspecting customer to pay for a network upgrade that ultimately benefits all the customers on that leg of the network.
The OP may benefit from having three phase installed as most electric boilers have multiple elements and the load could be spread across the phases and reduce the limitations that high load single phase appliances can have on an installation

 

[Taylortwocities]

Havent had a reply to this question

I guess the combi is a gas or oil device, ie not electric?

A non-electric boiler is going to be less than 3amp.

 

[GBDamo]

Havent had a reply to this question

A non-electric boiler is going to be less than 3amp.

OP mentioned it was an electric boiler up thread somewhere. He hasn't, as yet, let us know the rating.

 

[Taylortwocities]

Ah yes. In the first post(how embarrassing )

That will not help the VD, if that is the issue.