Re: energy in UK

On 19/04/2025 19:27, Don Y wrote:

On 4/19/2025 9:20 AM, Martin Brown wrote:

On 18/04/2025 22:57, Don Y wrote:

On 4/18/2025 1:19 AM, Martin Brown wrote:

Where I live in a rural backwater the mains is actually more like US style two phase and neutral rather than normal UK 3 phase.

>
Our mains is actually a 240V center tapped configuration (thus, single phase).
There are two "hot" leads -- each 180 degrees out of phase with the other.
The center tap is considered neutral.  It is typically bonded to earth
at the load center.

>
That is the same as in small rural villages in the UK except that each house is only on one of the two phases at 240v. ISTR US and Japan put their aircon across the antiphase pair to get the power handling up.

 It's also used for electric stoves/ovens, clothes dryers, etc.
 

Ideally, loads in the house are balanced on the two "legs".  An open
neutral connection is a recipe for disaster as the loads start to
see unbalanced potentials.

>
Our village hall has both phases present on 100A circuits 240v. There are warnings and duplicate distribution blocks for each phase.

 Ah.  So, it's as if it was located in two *different* villages?
What a mess!

No it has three wires coming in but they are just like in the US but 240v instead of 110v: phase+ neutral phase-.

Earth is mandatory in UK installations often a local earth copper spike nailed into ground at the premises and the shield of the underground cable. My electricity actually comes in as two overhead wires. This is now actually quite rare in the UK and only happens in rural villages.

 Each subscriber presents a local earth for THEIR load center.
The "nearest upstream" transformer also ties to earth.
 But, earth is not required (historically) at all loads.  E.g.,
our stove is a three-wire circuit -- two hots and neutral
(no separate earth).  This because of changes to the Code,
over time -- with older installations being "grandfathered" in.

Here anything with external metal parts should be earthed by law. Double insulated things or with no metal surfaces to touch do not have to be and can be on two pin plugs. Mains electric razors for instance.
Most UK ring main sockets *require* an earth pin to be present on the mains plug to open the mechanical cover over the live and neutral terminals. It was not always so. Previous round pin plugs you could poke a piece of metal or screwdriver in there and touch live!

This is a sore point with businesses that would like to use 3 phase equipment. Each village is across one pair of the 3 phase distribution line with a transformer ratio to give 240v output.

>

Each *village*?  How is that balanced?  Luck??

>
Quite possibly. It seems to work fine.

 What happens if a drunk takes down a "power pole" feeding said village?

Last time it happened was the coldest day of the year and it was the milk tanker hit black ice and took down 2 poles and 30' of hedge. There is no way he was doing 30mph! Engineers had us back on by nightfall.
--
Martin Brown