Single & 3-Phase Voltage in The UK

[pprendeville]

Hi all,

Just a quick question on single phase and 3-phase voltage.

Do The UK use 240V Single Phase and 415V 3-Phase?

 

[Mark.W]

It's actually 240V single phase but we say it's 230V, 3 phase is 400V!

 

[pprendeville]

Good man yourself.

 

[ian.settle1]

It's actually 240V single phase but we say it's 230V, 3 phase is 400V!

Correct amundo thats the voltages we all should be using now in Europe with harmonisation.

 

[Notsosmart]

Correct amundo thats the voltages we all should be using now in Europe with harmonisation.

Except nobody has seemed to told the voltage itself; 248v measured at socket outlets & 414V measured in 3 phase plant within our building

 

[Electurer]

We are now 'harmonised' with Europe and theoretically the voltages in the UK are 230 V single phase and 400 V 3 Phase.

Indeed, all of the relavent tables in BS 7671 (The 17th Ed Regs), are now calculated to 230 V. Examples of this can be seen in the Maximum Earth Fault Loop Impedance Tables in Chapter 41.

When we measure voltages in the UK the values are typically higher as quite correctly stated in a previous post.

But don't Panic - this makes thing safer as we have lower earth loop values to meet.

Incidentally, the only place that I know (there may be others) where you get a true 230/400 V is some of the ASDA stores!

So now you know - Hope this helps.

 

[Lee Gold]

So a voltage in a company/factory like jaguar etc the voltage is 400v?

 

[Darkwood]

So a voltage in a company/factory like jaguar etc the voltage is 400v?

This is a 6yr old thread but as you ask then Yes! between phases 400v and as usual any phase to N/E will be 230v.

Larger factories or heavier industry may even have higher voltage systems to distribute around large sites but for the general jist the 3ph supplies are the norm in factories and large commercial.

Note not every factory etc has 3ph some only 1ph especially the smaller units.

 

[Simonslimline]

The voltage in my flat is 248 at the moment from a socket.

The whole 230/400 is what we are taught at college, not really reality though.

 

[uksparks]

It is a bit illy how everything is based on something that's incorrect or not what it's supposed to be.

 

[Spoon]

It is a bit illy how everything is based on something that's incorrect or not what it's supposed to be.

Nothing is how its is supposed to be... Politicians are meant to look after the people but they are a bunch of liars. Companies say they are looking after their customers and employees when they are really just concerned about profit.... That's my Wednesday whinge over with.... grumpy man out.....

 

[telectrix]

400/230 is no more silly than brown/black/grey. 1 is as stupid as the other.

 

[bossian]

We have our own tranny and the tap it's set on with the 11kv coming in gives us 418/248 volts

 

[Besoeker]

400/230 is no more silly than brown/black/grey. 1 is as stupid as the other.

Disagree. A small change in nominal voltages (c 1%) for no good reason is silly. The harmonised colour change is utter insanity.

 

[andyb]

Disagree. A small change in nominal voltages (c 1%) for no good reason is silly. The harmonised colour change is utter insanity.

The supply voltage in the UK is 230v with a tolerance of +10% -6% which meant that when we harmonised with Europe the supply companies could still pump out 240v.

Why do you say that the harmonised colour change is utter insanity?

 

[Besoeker]

The supply voltage in the UK is 230v with a tolerance of +10% -6% which meant that when we harmonised with Europe the supply companies could still pump out 240v.

Quite. Nothing changed except tolerances So what was the point other than a bureaucratic fudge.......

Why do you say that the harmonised colour change is utter insanity?

And that was puting it mildly.
We now have black as one of the live phases when it was previously the colour for neutral and blue as neutral when it was a phase.

Look in a junction box where the old interfaces with the new, see a black wire connected to a blue.......the potential for confusion and risk is obvious. And for what?

An acquaintance of mine has a fairly large house in France and it has a three-phase service. It has been wired in RYB after these were proscribed in UK. My guess is that the tight wad got a deal on obsolete UK stock that would otherwise have had to be scrapped.

 

[andyb]

Quite. Nothing changed except tolerances So what was the point other than a bureaucratic fudge.......


And that was puting it mildly.
We now have black as one of the live phases when it was previously the colour for neutral and blue as neutral when it was a phase.

Look in a junction box where the old interfaces with the new, see a black wire connected to a blue.......the potential for confusion and risk is obvious. And for what?

An acquaintance of mine has a fairly large house in France and it has a three-phase service. It has been wired in RYB after these were proscribed in UK. My guess is that the tight wad got a deal on obsolete UK stock that would otherwise have had to be scrapped.

We've always had a tolerance with regards to the supply voltage. It's only the nominal voltage that's changed as it has in several countries throughout Europe when we harmonised. I never gave this a second thought, it really isn't a problem.

Black was as you say was previously neutral, but so was blue in flex. In my mind that was sillier. The key word is previously, it was black, now it's blue. An electrician should be able to cope with that.

 

[Besoeker]

We've always had a tolerance with regards to the supply voltage. It's only the nominal voltage that's changed as it has in several countries throughout Europe when we harmonised. I never gave this a second thought, it really isn't a problem.

And tolerances.

Black was as you say was previously neutral, but so was blue in flex. In my mind that was sillier. The key word is previously, it was black, now it's blue. An electrician should be able to cope with that.

Yes. Should. Let me give you a possible scenario.
You get called out to a breakdown in the middle of the night. Open a junction box in poor light. One side has harmonised colours, the other, the old system. Brown, black, grey, blue or RYB and black?

 

[telectrix]

We've always had a tolerance with regards to the supply voltage. It's only the nominal voltage that's changed as it has in several countries throughout Europe when we harmonised. I never gave this a second thought, it really isn't a problem.

Black was as you say was previously neutral, but so was blue in flex. In my mind that was sillier. The key word is previously, it was black, now it's blue. An electrician should be able to cope with that.

fine, but in poor light (where us poor sparks needs to work sometimes) these stupid new colours are all grey.

 

[andyb]

And tolerances.



Yes. Should. Let me give you a possible scenario.
You get called out to a breakdown in the middle of the night. Open a junction box in poor light. One side has harmonised colours, the other, the old system. Brown, black, grey, blue or RYB and black?

fine, but in poor light (where us poor sparks needs to work sometimes) these stupid new colours are all grey.

Disagree. A small change in nominal voltages (c 1%) for no good reason is silly. The harmonised colour change is utter insanity.

I'm obviously going to have to concede defeat with this.
For over 10 years I've been blissfully unaware of the problems that harmonisation has caused other electricians. I guess I'm one of the very few lucky ones blessed with average eyesight (assuming that I have my glasses on) and the ability to do basic testing.

 

[telectrix]

the whole concept of RYB was that these are primary colours and by their very nature (and in nature) are an indication of danger. i remember in the 90's IEE as it was then , made the wiring regs. a British Standard ( BS7671), ​with the intention of preventing johnny foreigner from interfering. PAH !.

 

[bomjac]

How I wish the UK voltage really was 230V.

Just this week replaced a dead Fridge Freezer, July a washing machine an Tumble Dryer. Voltage at my house is typically 248 - 253 volts. Highest I have seen is 259 back in July. Was the equipment damaged by the volts being high ? Maybe, but without a certified meter or power monitering equipment to moniter it for a week I am not really in a position to challenge Scottish Power.

Their response will simply be yes it is a little high, but within 10%. These bandits should at least be forced to change the taps on their distribution transformers to properly set the voltage.

 

[davesparks]

%. These bandits should at least be forced to change the taps on their distribution transformers to properly set the voltage.

Yeah, they could just flip a switch and plunge half the country into darkness

 

[sysrq]

How I wish the UK voltage really was 230V.

Just this week replaced a dead Fridge Freezer, July a washing machine an Tumble Dryer. Voltage at my house is typically 248 - 253 volts. Highest I have seen is 259 back in July. Was the equipment damaged by the volts being high ? Maybe, but without a certified meter or power monitering equipment to moniter it for a week I am not really in a position to challenge Scottish Power.

Their response will simply be yes it is a little high, but within 10%. These bandits should at least be forced to change the taps on their distribution transformers to properly set the voltage.

In our place we have a 245V on L1 and L2 and 255V on L3. That's the reason why motor current on one phase is always way too high. Another thing is control voltages are always higher, instead of 24VAC we have 28VAC or even 30VAC. For 24V contactors with AC coils it shouldn't be a problem cause if the voltage is too low it can do more harm than good.