Single phase, 2 phase, 3 phase etc

What does the above mean? How many phases does a regular 4 bed home have?

Electrically almost all regular 4 bed homes have just a single phase

Other phases can be single couple, babies, teenagers, darby and joan and probably many more.......

Thanks but what does it mean to have a two or three phase electrical system?

This is a reasonably good explanation in answer to you second question..

https://en.wikipedia.org/wiki/Three-phase_electric_power

Only ever once seen 3 phase in a domestic property. That was a massive new build bungalow (and I mean massive!) with storage heaters. The 3 phase was for the heating load.

have to admit I didnt understand that wiki. Why would a house have more than one phase? More power consumption, split into flats?

More to the point, why are you asking? Do you think you have a property with 2 or 3 phase? if so put some pics of the incoming main, meter, and consumer unit etc. Someone here will tell you.
As I said before the bungalow I worked on needed the three phases for the power used by the heating, although that was more about balancing the load than maximum load IIRC. Whatever the board insisted on it.

Dave54 said:

Only ever once seen 3 phase in a domestic property. That was a massive new build bungalow (and I mean massive!) with storage heaters. The 3 phase was for the heating load.

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Even though I don't really need it, I've got a 3-phase supply and, although my house is pretty large, it's no castle or mansion - but it's old. I believe/suspect that the main reason is historical - local knowledge suggests that, once-upon-a-time, what is now my house, right on the edge of a small village (much smaller 'back then'), was probably the only building in the village which had an electricity supply, which was provided by a pole-mounted transformer (successors of which were still there when I moved here some 28 years ago) that had nothing else to do other than supply the one building. They perhaps felt that, since it was a 3-phase transformer (maybe all they had 'to hand') they might as well run all three phases to the house ... and that situation has persisted ever since.

Kind Regards, John

Reasons vary greatly. High demand would be one, but a domestic single phase supply is generally 80/100a which is LOADS. if you have 3P equipment that would be one reason.

Flats are a prime use of 3P because you can balance the load out.

The flats I'm working on at the moment has 4 x 3P supplies. 9 flats, giving each of them a phase from their head, then one head for landlord supplies, outdoor stuff, cctv etc.

That being said I've seen 2 up two downs with a 3P head.

Dave54 said:

Only ever once seen 3 phase in a domestic property.

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You should get out more then…. there are lots out there. Not in your regular bungalow, I grant you, but lots.

In reality it is common to get a number of combinations based on load and capacity

Single phase with one fuse - the most common
Single phase barred (busbarred) with 2 fuses to use the higher capacity of the service cables and cut-outs
Single phase with two service cables on the same phase and 2 cut-outs
Split single phase with the above arrangement but 2 cut-outs, or into a 3 phase cutout with two fuses on one of the "phases" only found on rural networks
Two phase from a 3 phase network
Two phases entering a large older single phase cut-out with the second phase looping to the property next door
Three phase into a standard 3 phase cutout
Three phase into a barred cut-out to give 4 live fuses.

These can all be found on domestic supplies in this patch

In a three phase system there are three live conductors which are 120 degrees out of phase. There are several advantages of doing this. Firstly notablly the power transfer (assuming a balanced linear load) is constant unlike in a single phase system where it varies over the cycle. Secondly it can naturally create a rotating magnetic field which means induction and syncronous motors don't need special provision for starting.

Typically in low voltage (normally 230V/400V) AC systems there is also a neutral conductor and 230V single phase loads are connected between one phase and he neutral. It is also possible to have 400V single phase loads connected between two phases but this is less common. In HV (over 1000V) systems it is typical to not have a neutral conductor at all and to connect all loads between the phases.

In the UK it's rare to see three phase supplies in households but common to see them in commercial and industrial premisis where the total load is higher and large motors are more commonly used.

The term "two phase" can reffer to a few very different systems and you should always seek clarification as to what is meant. Originally it reffered to a system with two phases 90 degrees out of phase, this provided the rotating magnetic field but meant the neutral current was higher than either phase current which was considered undesirable and the system largely fell out of use. The term can also reffer to a situation where you have two of the phases of a three phase system or to a "split phase" system where there are two phases 180 degrees out of phase which is sometimes seen when a larger LV load needs to be connected to a single phase HV supply

I have a large property and the previous owner has one supply coming in from the street to the left side of the house which supplies most of the house and then another supply coming from the street into the garage which then splits to two meters and fuse boards, one to the loft annex and the other to the first floor annex. Someone might have mentioned to me that it was a three phase, but I didnt understand what that meant.

I am now converting the whole place back into one large house rather than these separate sections and will have to get the whole thing rewired including a discussion of one of the mains on the left side and remove one meter from the right side so I have one meter left....like normal people.

That does sound like a lash up. Best get on the phone to your supplier & DNO, they're the only people that can help you.

You currently have 3 meters?

plugwash said:

In a three phase system there are three live conductors

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Generally there are four as a neutral is distributed.