How many have 3 phase in a DOMESTIC house

[Ian ParkinParticipant @ianparkin39383]

My daughter and her husband recently bought a new house to them a pretty ordinary 1930's 3 bed detached in a suburb of Sheffield

I was amazed to see that they had 3 phase to the meter area and yes they are live

How many others have 3 phase at home?

[Ian ParkinParticipant @ianparkin39383]

[EmgeeParticipant @emgee]

Ian, not so unusual as the supply companies used to install 3 phase supplies to properties with off peak heating loads that could not be supplied by a single phase 60A supply, not so common these days with less people using such systems.

Emgee

Edited By Emgee on 19/10/2016 10:24:16

[Ian ParkinParticipant @ianparkin39383]

I did wonder if that's what it may be for but there's 3 100 amps here.

[AjohnwParticipant @ajohnw51620]

Houses are generally powered from 3 phase but only one phase for each. I've been told that in older houses in B'ham that the 3 phase supply is very often taken to the house but the wires may not be clearly visible.

Our house was owned by 2 spinsters who wanted separate bills so one floor is powered on one phase and rest on another phase. Annoying as we have to pay 2 standing charges. Same with gas.

If I looked closely I might find that the 3rd phase is there as well as the house was fitted with economy seven. Fitted by cegb. Did they use the usual 13 amp cable for wiring it – no, 'cause a lighter cable is cheaper. Personal beef as I could have used it for 13 amp spurs then.

It's an interesting area – houses have been built for a long time now that couldn't feasibly be heated and powered from a single phase. We import a lot of gas for heating. Maybe all 3 phases are near the meters but some how I doubt it as the builders will have wanted to save on cabling. People with older houses that also need more heating might not have a problem – if electricity ever gets costs effective. If 3 phase isn't easily available there will be a hell of a problem one day.

John

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[Brian HParticipant @brianh50089]

The last house I moved to had 3 phase built in as I found when I opened the meter cupboard and saw three 400 amp fuses.

I 'phoned the electricity company to confirm and was told that every third house has 3 phase but they didn't know why.

I got an electrician to run a supply out to the workshop/garage and sold my 1 to 3 phase converter.

The houses were built in 1946.

[Neil WyattModerator @neilwyatt]

We have two 80A fuses, both on the same phase, one for the house, one for heating.

1937 but a more modern installation.

Neil

[SillyOldDufferModerator @sillyoldduffer]

I have a single 100A for both house and heating (1971). The single phase is tapped off one of the 3-phases on a pole 10 metres away. I think it would be cheap and easy for me to get 3-phase, but – Sod's Law – I 'm unlikely to ever want it.

My previous house would have been costly to upgrade to 3-phase. All the cables were buried and came from a substation at the end of the road.

Does anyone know if adjacent houses are on the same phase or not? Could be 'interesting' if my neighbour and I both ran extension cables to a shared job!

Dave

[AjohnwParticipant @ajohnw51620]

Must admit I don't know what they are doing with the supply to new houses now. My comments were based on lots built from the mid 50's and if I recollect correctly 60 amp fuses. I dom't know what cable ratings they used to the house.

The reason we ditched economy 7 is that the house has to be heated all day. To do that with the storage heaters they fitted we had a boost mid day at the same price. The gas bill was a hell of a lot cheaper after it was installed. That was done sensibly though. I designed it with some help from a guy who thought it was about time that some science was introduced into central heating and produced a good booklet on pipe design etc. I also fitted thermostatic radiator valves all round, just one small one to cope with boiler over run. The rad valves have been set to suit. The thermostatic rad valves allow the boiler to only output 1/2 of what the usually put out in houses like ours. The radiator sizes have been calculated to keep the temperature down as well. The gas board did a survey and found my heat loss calculations and agreed with them. I'd had several people in and didn't like what I was hearing. They were the only ones that seemed to know what they were doing but I thought more radiator would be a good idea.

The boiler needs changing now. Currently it has a small heat store for hot water. Big enough to fill a bath and the water will cool after that but be back up to temperature 4 mins later. Usable well before that. These days they would have me fit a massive heat store. If that cools it will take a long time to heat up. What to do? I do think that style of water heating is the best though and if some one suggested fitting a combi I would show them the door.

John

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[Brian WoodParticipant @brianwood45127]

Hello Dave,

​The street cable will carry 3 phases which are split off to houses along the street in some attempt to balance the loading along the cable. So, yes, it could be interesting if you and your neighbour share power supplies on a common job.

​When we lived in the Dales, our neighbour in the field below us had a different phase supply to her house from ours. We both had night storage heaters.

The local farmers bullocks brought down the overhead power pole crossing the field which tore the neutral cable in half, leaving these wretched beasts to chase a sparking snake about in the field. We suffered serious collateral damage in the incident, all the lighting went pop, electronic equipment actually in use fried and fridge motors ran at insane speeds before burning out

We of course had been acting as the return path to the full load of her cooker and with the inter phase voltage of ~380 volts running through everything we had switched on.

Regards
Brian

[Nick_GParticipant @nick_g]

.

It was very common at one time to bring 3 phase into all the houses in a street.

The 'cut out' as they are know to the supply authorities (the block that holds the main fuses) would have a single phase then tapped off to the meter.

The next house would be on a different phase and the next house again would be on the third phase ……….. And so on down the street. – This would in theory keep the supply cable phases 'reasonably' balanced in load.

Nick

[EmgeeParticipant @emgee]

Dave, adjacent properties were normally connected on different phases to assist with a balanced load across phases.

Neil, does your supply have 3 lines coming in ? if you are in a rural location could be 2 lives and a neutral, same phase but 480volts between the 2 live conductors.

Emgee

Nick beat me to it !!

 

Edited By Emgee on 19/10/2016 11:49:33

[Roger HulettParticipant @rogerhulett83124]

Many years ago I lived in Scotland. There was a 3phase supply to one of each pair of semis,with one phase going to the adjoining house. Unfortunately I didn't know that,and whilst trying to establish why I had so many wires in the box managed to "blow" the whole street's power supply !

[AjohnwParticipant @ajohnw51620]

I made another change to the heating that seems to have cut costs. I fitted a wireless thermostat in the lounge. No thermostat in the room that has the small uncontrolled radiator in it for boiler over run. Both rads in the lounge do have thermostatic valves fitted. It's cut down the "heat bounce" in the system so the boiler shuts down sooner.

It seemed worth trying to me as that is where we need more precise temperature control. The bathroom with the over run rad does get a bit warm but not uncomfortably. It's possible to get boilers now that can have thermostatic valves fitted to all rads.

John

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[MuzzerParticipant @muzzer]

Almost certainly the presence of a 3-phase incomer indicates that the house used to have electric heating. There's not much else that would require such a large power capability, short of an industrial annexe.

My parents' house in Harrogate had 3-phase when we acquired it in the mid seventies when it was about 10 years old. There was underfloor electric heating in all rooms (it's a large bungalow) and 3 meters in the garage. Resistance wires were simply run in steel conduits in a concrete slab sitting on polystyrene insulation. Obviously we ripped all of this out and replaced it with GCH. The 2 additional meters were removed not long afterwards.

I expect you pay extra for the additional 3 phases, both installation of the meters and their rental, so even though the connections are there, making use of them might be a bit extravagant for hobby use.

[Anonymous]

As far as I'm aware I don't pay extra standing charges, or more per kWh, for my 3-phase supply than I would for single phase. After all the house, which is the main consumer, runs off a single phase. It's just that the tapping is in my garage rather than the street.

Andrew

[J HancockParticipant @jhancock95746]

I well remember the days in the 1960's when Pembroke+ others were using heavy fuel oil to 'make' electricity.

We had a student in the class, who worked for the EEB, selling storage and underfloor electric heating

to all the new housing developments in the area.

I wiil bet they have all changed to gas heating now !!

[Neil WyattModerator @neilwyatt]

Posted by Ajohnw on 19/10/2016 11:34:03:

These days they would have me fit a massive heat store. If that cools it will take a long time to heat up. –

More usual to have a combi boiler with a tiny heat store these days, it can fill a washing up bowl or wash your hands without going into overdrive, but when you need a bath or shower it just runs flat out.

We've got one and it works.

N.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Neil Wyatt on 19/10/2016 18:14:21:

Posted by Ajohnw on 19/10/2016 11:34:03:

…

More usual to have a combi boiler with a tiny heat store these days, it can fill a washing up bowl or wash your hands without going into overdrive, but when you need a bath or shower it just runs flat out.

We've got one and it works.

N.

Ah the good old days! Remember when being last in the queue meant a cold bath#. And those semi-exploding Gas Geysers in freezing Bathrooms.

I expect Duncan will pop up to explain that such things were luxury when he were a lad in't Yorkshire…

# For readers not used to UK hygiene: we Brits like to start the week by sitting in a few inches of dirty water whether we need it or not.

[AjohnwParticipant @ajohnw51620]

Posted by Neil Wyatt on 19/10/2016 18:14:21:

Posted by Ajohnw on 19/10/2016 11:34:03:

These days they would have me fit a massive heat store. If that cools it will take a long time to heat up. –

More usual to have a combi boiler with a tiny heat store these days, it can fill a washing up bowl or wash your hands without going into overdrive, but when you need a bath or shower it just runs flat out.

We've got one and it works.

N.

If you fitted our new boiler Neil I'd throw you out. Combi's are often thought of not being a good idea if there is more than one bathroom. The heatloss from the heat store is negligible. In my view the man that started up Worcester heating was a bright cookie as far a running costs are concerned. The boiler scarcely ever turns on unless hot water is run. The only catch with them is that people have to accept that the water will run cool eventually when filling a bath. This is why it's such a small heat store as it's never too cool for many things. In some ways it's similar to having a combi with a separate tank that's kept hot all of the time.

There is no direct replacement now so I am left with the question how big a heat store. The current one holds 10 gallons which is why it can supply moderately hot water when its run down. Too cool for a bath maybe but it's used to cool the water that is way too hot. It heats up in about 4 min to 80 odd C.

Some friends of ours used a rayburn for heating and the heat exchanger went. Similar problems to us. The guy that got the job said no combi for a number of reasons. They have en suites. To posh for us we just have bedroom sinks instead. We have a room that could be an en suite and 2 bathrooms.

John

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[Max ToleranceParticipant @maxtolerance69251]

I have a three phase supply fitted for "free" by the old NWEB. My house was built around the turn of the century (1901). In those days electricity was a new thing for houses and if a new house wanted to be connected to the mains as it was called then, they used the tram supply generated by the local authority. The only problem was that this was usually D.C. When the national grid was set up later then of course the supply changed to A.C. and voltages where standardised.

In my street when the national grid was connected they decided to use the original two core D.C. supply cables so one phase went down one side of the street and a different phase went down the other. Later a three phase cable was laid to supply the street lights, however they left the houses as they were. Around twenty years ago the supply cable to my house failed (after all it was approaching 100 years old) it was a lead and paper insulated cable and very light by modern standards. The electric board were very busy at the time so In exchange for me digging the trench across my front lawn they kindly agreed to fit three phase power for "free". Happy days!

I only pay one standing charge and standard tariff, the only down side is finding a supply company who will accept three meter readings instead of one since most of them unbelievably can't cope with it for domestic customers. But if you want to fill your cellar with machinery you can't beat it.

[AjohnwParticipant @ajohnw51620]

I found out that the ground floor was on one phase and the 2nd on another when one of the phases blew in the street. I assumed one of the meter main fuses had blown.

When they fitted smart meters they booked an appointment and didn't turn up. When we phoned up they told us that there had been a mistake as 2 appointments had been booked so they decided not to visit. They then rebooked and the same thing happened so the guy said don't worry I'll cancel one of them. Hang on I said we do have 2 meters. A you might guess we now have one smart and one not smart electricity meters. 2 gas meters but serviced by 2 different suppliers. Can't get one to accept both but haven't tried that hard. They wouldn't give us a 2nd dual fuel deal as we already had one for the ground floor supplies.

Argggggggg.

John

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[not done it yetParticipant @notdoneityet]

Most farm houses would have a 3 phase supply – well, ours did. But normally only the one phase for the house electrics.

Running adjacent houses on different legs of the three phase allowed better load sharing. A large property might have used two phases (so care required with connecting extensions between them!).

Just not really needed, these days, with VFDs, for most domestic requirements. Only really need extra phases for all-electric heating, running hard-start motors in excess of 3HP, or really heavy duty welders, I would suggest. Our lights dim considerably when I use my welder and we have a 100A supply (I think)! Not sure what the extra running cost of a 3 ph supply might be, but installing extra phases normally costs an arm and a leg.

[John OlsenParticipant @johnolsen79199]

It is usual to try to balance the load on the phases, so it is quite probable that a neighbour is on a different phase. All you need to do to check this is to measure the voltage between his phase and yours, using a suitable scale on the voltmeter of course. It would not be a good idea to try to parallel them to get more current anyway, since one lead will probably have more resistance than the other, so you will blow one fuse first, followed very quickly by the other, at not much more than the normal current for one lead.

In this country, it used to be not uncommon for the stove to be supplied by one phase while the rest of the house was on another. This would actually provide an opportunity for anyone who needed three phases, since with a suitable connection of two isolating transformers to the two phases, you can actually create the third. I've never heard of it actually being done, and it would probably be against the regulations, but it would work. These days it would be much easier just to use a vfd.

Incidently three phase welders of the older style, eg with just a transformer, actually only used two phases, with a transformer primary connected to them. The rod can only have single phase power going through it. Modern ones with an inverter probably use all three, as they will rectify the AC then chop it up again, much like a vfd does.

John

[Colin WhittakerParticipant @colinwhittaker20544]

Three meters for three phases!

Here in Thailand most big houses have a three phase power supply because of all the air conditioners. The three phase power is measured with a single three phase meter. I wonder why the UK is so backward?

Colin

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