ELECTRICS NEW LIGHTS ON EXISTING CIRCUIT (IN BACK OF STAIRS)

[EFLImpudence]

It appears I have suffered some confusion. First UK voltage. As I said it has been nominally 240v for a long time,

It was. It no longer is.

230v in NI. Europe including the Irish Republic 220v.

Now 230V in Great Britain, too.

Harmonisation has come along and the nominal voltages have not changed,

It has in Great Britain.

only the tolerances have changed.

The tolerances changed when the nominal voltage changed.

However to please the Eurocrats it is now incorrectly referred to as 230v.

Not incorrectly. The nominal voltage is 230.

To base calculations on this incorrect figure is madness, no real engineer would do it. I've just measured the voltage at home and it 242v.

Presumably allowed.

LED lights and LED drivers are unlikely to have unity power factor. The correct formula is current = watts/volts x power factor or I=W/Vcos phase angle. The best way to know load current is to measure it.

That cannot be done when designing, i.e. architects etc.

Whether you want one driver per LED is up to you, but it does seem wasteful considering LEDs use so little power.

That depends.

All lights out if the driver fails is irrevelvant in this case as the lights are not in the same place as the driver anyway.

 

[EFLImpudence]

Just thought - do you know what 'nominal' means?

 

[JohnW2]

First UK voltage. As I said it has been nominally 240v for a long time, 230v in NI. Europe including the Irish Republic 220v. Harmonisation has come along and the nominal voltages have not changed, only the tolerances have changed.

You seem to have got the vocabulary a bit wrong. Although actual voltage has not changed, the 'nominal' voltage has, as well as the limits/tolerances. That's what the '230V' is all about.

As you say, if one wants a fairly accurate figure for current, the best approach is to measure it. Although you have been making a point about PF, I suspect that losses in power supplies are at least as important (they can get quite hot!).

Kind Regards, John

 

[winston1]

.[/quote]
You seem to have got the vocabulary a bit wrong. Although actual voltage has not changed, the 'nominal' voltage has, as well as the limits/tolerances. That's what the '230V' is all about.
[/quote]

Point taken. But the fact of the matter is that for calculations it makes sence to use the actual voltage, rather than some fictichous figure dreamed up by Eurocrats.