Number of 'electrical phases' ?

On Fri, 18 May 2007 21:53:25 +0100, John Rumm mused:

And the motor parked on the drive. ;)

That's another keyboard that will take a few days to dry out :-)

Thanks

Dave

Why don't you ring the number on the form and ask? Most houses are single phase, it's only factories or some shops and workshops that are 3 phase. Each street has 3 phases, so as you went along each was on a different one. So it used to be like this -

1. red
2. yellow
3. blue
4. red
5. yellow
6. blue

and so on. You get 415v between phases and 240v between each phase and earth. The colours have changed now, but they are the ones you find on most underground cables. It's for people with gigantic demands for power, or more than that of the average house.

Just make sure that your mains cable coming in to the house is not split between 2 houses. This used to be common practice in the 50's and 60's in some areas! It's caused a lot of house fires when the cable between the street and houses has become overloaded - especially after people had storage heaters installed.

No, R-Y-B-B-Y-R-R-Y-B-B-Y-R etc., usually.

|! |!> and then: "How many electrical phases?" |! |!Go on. Ask for 5.

In the dim and distant past I ran *two* phase motors. If you want to confuse them ask for 2.

Was this just tradition, or is there justification for doing it this way? (like it uses all the phases but creates the smallest number of adjacent properties that are on different phases?)

We are just having an additional 2MW supply installed at work, and all the new 3-phase supply cabling is still R-Y-B in that.