is it 230v or 240v?

[Discharged]

Why is mains domestic power referred to as either 230v or 240v? Why not settle on just one of them? (My limited knowledge tells me that the reality is usually 243v or 237v - is that right?)

Cheers.

 

[Deleted member 19807]

230v is to bring us in line with europe and 240 is what our power stations kick out.

 

[topquark]

Currently nominally 230V, allowable to be -6% to +10%.

 

[nickblake]

couldnt have said it better topquark

 

[MarkieSparkie]

The supply industry has actually done nothing physical to reduce the nominal supply voltage from 240V to 230V, it's still 240V open circuit at the terminals of the local supply transformer. What has changed, as part of European harmonisation (Cenelec HD472), the declared nominal voltage has changed from 240v +-6% (between 225.6 and 254.4V) to 230V +10% -6% (between 216.2 and 253V), very little change, just a slightly wider margin at the lower end. This suits the DNO's just fine as it gives them a bigger window of acceptable supply voltage in rural areas, without the associated costs rewinding transformers or tap changing.
Note:- A second round of change in the declared nominal supply voltage (Cenelec HD472-S2) 230V +-10% is pending, it was due on 1/1/2008 but has yet to be implemented in the UK.

 

[bumcrack]

230v is to bring us in line with europe and 240 is what our power stations kick out.

Our power stations generally kick out 400kv. 230-240 is what you get depending on network demand and transformer tapping.

 

[Engineer54]

You can dress it up however you want to, what you have is what you have, ...and that's 415/240V
The rest is just hot air and the land of make believe!! lol!!! I guess you can call it the same as creative accounting... lol!!!:rofl:

 

[alarm man]

ive had issues with security systems with monitored power supplies that throw a wobbly at anything over 250v and quite often see it rise to 253-255v on site in off peak times,advise customer to complain to dno and surprise theres no fault to be found but the supply voltage is a nice 235v on next visit..

 

[Deleted member 26818]

The supply industry has actually done nothing physical to reduce the nominal supply voltage from 240V to 230V, it's still 240V open circuit at the terminals of the local supply transformer. What has changed, as part of European harmonisation (Cenelec HD472), the declared nominal voltage has changed from 240v +-6% (between 225.6 and 254.4V) to 230V +10% -6% (between 216.2 and 253V), very little change, just a slightly wider margin at the lower end. This suits the DNO's just fine as it gives them a bigger window of acceptable supply voltage in rural areas, without the associated costs rewinding transformers or tap changing.
Note:- A second round of change in the declared nominal supply voltage (Cenelec HD472-S2) 230V +-10% is pending, it was due on 1/1/2008 but has yet to be implemented in the UK.

I think you'll find that it used to be 240V + or - 10%.
The 6% only came in with the change to 230V.
If you do the calculations, you'll find both come out at 216V.
The only thing that has really changed, is that the suppliers are now not allowed to supply a voltage over 253V, whereas in the past they were allowed up to 264V.

 

[UNG]

I think you'll find that it used to be 240V + or - 10%.
The 6% only came in with the change to 230V.
If you do the calculations, you'll find both come out at 216V.
The only thing that has really changed, is that the suppliers are now not allowed to supply a voltage over 253V, whereas in the past they were allowed up to 264V.

The 240v +/- 6% is correct the 230v +10% was done so as not to disadvantage the uk supply industry as it lowered the allowed upper voltage marginally from 254v to 253v

 

[mogga]

if your filling in certs its 230v 400v as this "standard " was harmonised with the rest of europe Older sparks like myself still refer to 240 n 415 tho

 

[Mr.Si]

I always thought it was 230 +/- 10%, so 217 to 253...

 

[Silly Sausage]

And don't forget that 230V (400V) is the Nominal Voltage U[SUB]0[/SUB] that you use for your design calculations.

 

[UNG]

I always thought it was 230 +/- 10%, so 217 to 253...

230v +/- 10% by my maths is 207v - 253v

 

[Rockingit]

.....and no you can't try and cheat cable voltage drop calculations by starting off at 245V......

 

[Mr.Si]

230v +/- 10% by my maths is 207v - 253v

My bad! Yes, 207. It is a bit low but that is what I thought it was.

Sent from my Samsung Galaxy S II via Tapatalk

 

[ackbarthestar]

I very rarely see 230V on local sites, usually hovers around the 240- 245 mark. But then I live in a place where we don't get mobile phone reception and TV arials are 10ft high and Father Christmas takes up all the parking spaces. The positives are nobody worries too much about 3% on lighting circuits.
As stated previously, Uo = 400V/230V;
As stated in BS7671 app. 2 Uo = 230V +10% / -6% which equates to 216.2V - 253V

 

[Deleted member 26818]

The 240v +/- 6% is correct the 230v +10% was done so as not to disadvantage the uk supply industry as it lowered the allowed upper voltage marginally from 254v to 253v

Yes sorry, + or - 6% for 240V, then changed to + 10% - 6% for 230V.

 

[Rockingit]

Just out of interest, does anyone know if as the DNO's are building new sub stations and installing new transformers on poles, if they're done at 230? Because, wouldn't they use slightly less metal in the windings and therefore be cheaper??

 

[DurhamSparky]

i would assume that DNO are installing the same kit that has been mass produced for the last 40 years..!