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.

 

[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..!

 

[Rockingit]

No, no.....I know what's happening. The DNO's are cleverer than all of us. They have the gift of prophesy, and their Sayers predicted the Vote Of Cameron and the death of European Integration.

 

[Knobhead]

Most voltage regulation is done at 33/11KV via on load tap changers. In reality it’s easy to drop the voltage but there’s an awfull lot of transformers to change. If the DNO’s did drop the voltage they would be loosing revenue, so I can’t see them falling over themselves to do it.

I did drop the voltage on one site I worked on from 11400V to 10800V but I had to do it late on a Sunday night so I had minimum load on the system. I also had to do it in stages so it wasn’t noticed by our domestic consumers. Got to admit it was fun balancing 4 20MVA transformers. The tap changers sound like their being violently sick as they change. The reason for doing it was we had a problem with VSD’s burning out.

 

[llywelyn111]

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

25kv-30kv they kick out, then upped to 400kv to the super grid

 

[Engineer54]

25kv-30kv they kick out, then upped to 400kv to the super grid

Power stations generator's do not kick out 400kV, that voltage is from step-up transformers, to strings that are going to be run over long distances that link with other power stations, on a super grid network. 400KV gets stepped down many times before you see it at the local MV /LV distribution TX sub-stations...

 

[ackbarthestar]

I agree with E54. Generators generate 25kV and then are stepped up outside the shed to a transmission voltage of 400kV