Club 80-90 Forums

I have just taken over a building that has 3 phase electrics coming into it.

I don't fully understand what the implications of this are for me. Can anyone explain this simply?

There is a distribution board just by the meter, then 2 further distribution boards.

The electrics appear to be normal operationally and normal items plug in normally.
Is the 3 phase element specifically for 3 phase items hard wired into the main distribution board?

They are idependant of each other. You'll have 2 meters.

treat each phase as a single supply,the 3 phase is mainly for industrial gear as in nice big compressors and juicy migs etc
mm

Three phase basically means that you've got three separate AC electricity supplies coming into the building which all have the same voltage, frequency and current. The only difference between these three supplies is that the 'phase' of the any of them is offset by a third of a wavelength from the other two.

There are advantages in this with regard to efficiency in cabling and power transmission that are useful in supplying high power machinery. Also in a theatrical setting it helps to put the sound and the lighting equipment on different phases - this stops the sound equipment picking up AC hum from the lighting equipment.

You should be able to plug single phase equipment into any of the three supplies without issue, but what generally happens in building which only requires a single phase installation is that only one of the phases is used to supply the building, and the others would be 'capped off'.

It is really just three lots of 230v. If you are not using three phase gear then it will not affect you but if you get some it is good to know it is there. I always remember being asked by a car park barrier installer how he can get his 230v from the 400v board that was installed. I asked him if he didn't know then should he really be in there? Pleb.

My old house had three phase. When I had it rewired my leccy used one phase for each floor and the three phase was used for the Colchester lathe in one of the workshops.

Oldiebut goodie wrote:My old house had three phase. When I had it rewired my leccy used one phase for each floor and the three phase was used for the Colchester lathe in one of the workshops.

you lucky lucky b......

Then I got divorced, 7 bed detached Edwardian house, 1/3 acre.....etc all went!

The transformer that serves us and the houses around us is up a pole _right_ behind where my new garage is going to be.

But it's only a single-phase transformer. Pity, because all three wires are in the 11kV lines feeding it. It's just been replaced, too - and I forgot to ask 'em when they were planning it if they wouldn't mind putting a 3-phase one in, just in case... <grumble>

then you buy cheaper 3 phase stuff and then move house
mm

The loss of the croquet lawn and the 3 phase was worse than losing the wife!

One thing of note, at work in our lab/workshop we had lots of electrical sockets all wired to different phases

Electrician pointed out if you have one piece of 240v kit on one phase and one on another you have 415v between them, not normally a problem but potentially dangerous where electrical kit is in pieces switched on and next to each other as we do.

all rewired to one phase now

My Dad has three phase in his garden shed. I know he had to move heaven and earth to get it.

We've got both here which is standard.
The 3 phase is used in the kitchen, 1 phase for the oven, 1 phase for the left hand hot thingies and 1 phase for the right hand hot thingies.

I also have 3 phase in the garage and in my barn.