Does anyone think that 3 phase may become a practial proposition four houses to enable better electric car charging in the future? Is there really much more involved in the scheme of things for new build areas?
A 1974-built house near me seems to have had a 3-phase charger installed (it looks a lot bigger than the normal type 2 car chargers) and EDF closed the road while they dug a trench, presumably because there was a higher capacity cable on the other side. Houses built on both sides of the road.
My house is on the yellow phase and houses opposite are on blue phase, so
3 phase is piped to our development.
I would imagine that all three phases pass down virtually every street. Only properties requiring three phases will be supplied with it though.
Tim
Whats that in new money please?
I am too young to know the old phase colours, I only know the new phase colours!
:-)
What would the criteria be for a domestic house to have a 3 phase supply?
S.
We have a system that there are eight flats in the close. The supply is three phase (three fuses at the door). The flats are 3+3+2 across the phases. I understand the close next door will be 2+3+3 then 3+2+3 etc to balance the load.
If there is a power cut on one phase, enormous puzzlement results.
jon submitted this idea :
How do you know you are on the yellow phase? Phases are only identified in a number or colour sequence, for phase rotation purposes - the 'firing order' of the peaks, in relation to each other.
An high enough demand, or a customer willing to pay the cost of installing it and the higher standing charge.
Scott laid this down on his screen :
Idea is to minimise the current on the neutral.
A lost phase always causes confusion.
At one time, all houses were fed 3 phase, but only used one. This house is, for some historic reason, fed with 2 phases.
A wholly ignorant question but how does the neutral work? Is it another earth or is it returned to the substation?
Would you get a lower unit charge? I think I saw a suggestion that three phase is more efficient.
Are there any special rules about balancing the phases (within one property)?
Surely the whole point of using 3-phase would be that it was *smaller* than the same power in single phase.
Scott formulated on Thursday :
You would need to ask a potential supplier those questions, it can vary on supplier and area.
Might be wrong, but I thought normally 3 phase on a property was only fed to three phase loads, with a separate single phase supply for other loads. (At least, that is how it is at a very small commercial property that I know).
Certainly running different phases "nearby" is deprecated because of the higher phase to phase voltage.
I was thinking the same. But if using accurate timing and a reference it should be possible to work out which phase you are on.
I'm sure in the network they are well defined. Woe betide an engineer swapping a couple!
Scott brought next idea :
The neutral will be at or around the earth potential, maybe 20v maximum.
It is there to balance up the differences in the loading of individual phases. One way to look at it, is a street of houses, where each house is sequentially on phases 1,2,3 then 1,2,3 and so on all along the street. Adjacent houses will be across three different phases and if reasonably balanced loading between the three, there will be little actual current flowing in the neutral.
Sometimes the sequence can be 1,1, 2,2, 3,3, 1,1 and so on. I share the same phase with the other half my semi.
Suppliers like a nicely balanced load across the three phases, because it is more efficient.
Between phases the voltage is 415, between any phase and earth/neutral it is 240v.
Current will flow from say house 21 on phase 1, to 23 on phase 2, then to 25 on phase 3 rinse and repeat at 50 hertz, but the neutral acts as the return linking the three houses. That assumes all three houses are each consuming the same current. If not, then the neutral has to carry the return current to a more distant house, to balance itself against.
If you compare the three phases to a three cylinder engine, they are out of phase with each other by 120 degrees - one phase will be sucking, one blowing and the last one doing neither.
That over simplifies it, it might seem complex, but the basic idea is simple once you grasp it.
newshound brought next idea :
No, you normally get the three phases, via one three phase meter. The customer then takes his single phase needs from one or more of those, plus the neutral. Where a premises was previously split in two with
3-phases to one, single phase to the other, then you might combine them and have a three phase supply, plus the single phase supply.No, but there are regulations intended to help prevent two phases in use, coming near to each other, such as 13amp sockets on different phases. You can have for instance three banks of lights, one on each phase.
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