OT: american and european el. power system

darrenj · Mar 11, 2006

Being a sparky i have come across many different voltages..To get a true 220 (or 230 or 240)v service here we bond (to ground) one leg rather than the center tap..This gives you 220v to ground..(A money saving tip to people who buy an oversees machine..build your own cord!! a spilt plug will give you 220V)..

I believe this is how it is done in europe..

If you want 480 (Or 400 now i guess) that is a diffent service.. Just like getting a 208 service or 600..

D

PLucas · Mar 12, 2006

Lancie1 said:
How is the grounding done in residential wiring in the UK? You say that the system voltage is "230/400 VAC". Does this mean that (for each home or apartment) there is somewhere a 3-phase transformer (perhaps feeding other residences) that has 400 volts phase-to-phase and 230 volts phase-to-neutral? Do the transformers have "wye" secondaries, with a grounded neutral?

Lancie1

There is 'somewhere' a 3 phase transformer with a star (wye in US speak) secondary, the neutral leg is bonded to earth. This gives 230v phase-to-neutral (and phase-to-earth) and 400v phase-to-phase, as you mentioned.

This transformer will feed numerous properties, there is not one per building.

Paul

504bloke · Mar 12, 2006

Lancie1 said:
Dave,

How is the grounding done in residential wiring in the UK? You say that the system voltage is "230/400 VAC". Does this mean that (for each home or apartment) there is somewhere a 3-phase transformer (perhaps feeding other residences) that has 400 volts phase-to-phase and 230 volts phase-to-neutral? Do the transformers have "wye" secondaries, with a grounded neutral?

For most homes in the US, the utility service transformer is a single-phase 2400 primary to 240 volts secondary, with a split secondary phase, with the center point grounded to earth.

The US electric utility companies buy raw generated power in 3-phase units, but most residential customers use single-phase power. To make this work, the local electric company has to run residential wiring in a series of triple circuits, with each trio of circuits (Phases A, B, & C) feeding roughly the same number of homes or businesses. When one phase becomes loaded much more heavily than the other two, then the voltage levels may go out-of-range.

Going on from what Paul Said

There are also many ways the electricity company can terminate your supply in your home. These can be

PME (TNCS) - Used widely
TT Used widely
TNS Used widely
TNC Not common
IT Special purposes (Generator and Medical)

This looks confusing and complicated, for what the letters mean ie T in TNCS etc see this explanation http://www.tlc-direct.co.uk/Book/5.2.1.htm

For examples with drawings see the following examples that give a better explanation than i can

TT See -
http://www.tlc-direct.co.uk/Book/5.2.2.htm

TNS See -
http://www.tlc-direct.co.uk/Book/5.2.3.htm

TNCS See -
http://www.tlc-direct.co.uk/Book/5.2.4.htm
and for PME see
http://www.tlc-direct.co.uk/Book/5.6.1.htm
http://www.tlc-direct.co.uk/Book/5.6.3.htm
http://www.tlc-direct.co.uk/Book/5.6.4.htm

TNC See -
http://www.tlc-direct.co.uk/Book/5.2.5.htm

IT See -
http://www.tlc-direct.co.uk/Book/5.2.6.htm

Lancie1 · Mar 12, 2006

This transformer will feed numerous properties, there is not one per building.

Paul, if that was done where I live, they would have to run the secondary 220 volts several miles to get into numerous properties! At 200 Amperes per home, I think the voltage loss would be prohibitive.

As I type, I am looking out at my front yard and see the pole-mounted transformer. There is nothing connected to it except my home and 3 barns, all on the same electric meter.

504bloke · Mar 12, 2006

We have either 63 (older) or 100Amp (newer) supplies in homes.

Most towns are run as Paul states, i can look up my street and at the end of the road is a large transformer sub station that feeds i guess some 50 houses.

In rural communities the odd house that is far away from neighbours do sometimes have there own small pole transformer for there own feed.

Lancie1 · Mar 12, 2006

Dave,

100 Amps? That would barely run an air conditioning system and a cookstove! Oh, I forgot, you don't need air conditioning there! How nice. I am enjoying the few weeks of the year here when I can actually go outside without melting down. By June it will be 30 degrees at 95% humidity.

darrenj · Mar 12, 2006

Lancie1 said:
Dave,

100 Amps? That would barely run an air conditioning system and a cookstove! Oh, I forgot, you don't need air conditioning there! How nice. I am enjoying the few weeks of the year here when I can actually go outside without melting down. By June it will be 30 degrees at 95% humidity.

100amp is TONS unless you have electric heat (But whoo the hell can afford that!!!

)..I have a 100amp service i also have AC ,Electric stove, Electric hot water, electric dryer and a Hot tub that uses about 30 amp..So far i have never had a problem..

D

Lancie1 · Mar 12, 2006

well, er... I have elctric heat, and gas heat, and a wood heatrr, in case one system goes out. The electric heat is a water-source heat pump, so it is efficient for this climate. But here the heating season is short and getting shorter every year. In a few years I may take out one or two of the heating systems.

Rod · Mar 12, 2006

RE: 400Hz aircraft

When I was assembling aircraft I was told the 400 Hz required less cable size to deliver the current load. Also allowed for much smaller motors. Less weight = more fuel or stores or legs(distance)

Much like the Current/Voltage seesaw

But what do I know,
Rod(The CNC Dude)

seppoalanen · Mar 13, 2006

504bloke said:
Most Uk ( i assume this would be the same for european) have a single phase 230vac 50Hz supply and not 3 phase.

In Finland we have 3 phase system for every houses, 400/230VAC.

corkers · Oct 13, 2006

Lancie1 said:
Dave,

100 Amps? That would barely run an air conditioning system and a cookstove! Oh, I forgot, you don't need air conditioning there! How nice. I am enjoying the few weeks of the year here when I can actually go outside without melting down. By June it will be 30 degrees at 95% humidity.

Don't forget that we are working at 240V nominal supply voltage and 100A gives you 24,000W which is equivalant to 200A at 120V...

OT: american and european el. power system

darrenj

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