Street lights in EuropE....Mains supply

Hello,
Are UK/Europe streetlights supplied with single phase mains (230VAC), three phase mains, or line to line mains (415VAC)?
Answer needed for LED types and sodium/induction types

At least in the US, it is one phase of 480V vs neutral, or 277 volts.

This is a very common illumination voltage.

Thanks, i didnt realise the USA had a 480VAC (rms) distribution voltage, presumably for stuff like street lighting etc.
I thought USA would use the 200VAC line to line voltage for street lights.

I think some areas, at least in the UK, still apply a small DC offset to 230V AC to turn on/off lights wired in a group. They certainly are not three phase and I'm not sure if the phase used isn't selected randomly at time of installation.

Brian.

thanks, for the ones with offsets, they must be on their own little microgeneration mains network?

It makes me wonder, with a long line of street lights, like along a motorway, if they are all off single phase mains, then how can they balance out the neutral returns? (because any single phase, if you go back far enough in the supply network, must have come from a three phase feed?)

I have no idea about the phases but it does seem sensible to 'stagger' the phases to prevent imbalance.

Many years ago I did some research into failures of TV power supplies, the results were surprising. I should add that the standard technology at the time was to use a filter at the AC input and then an SCR to chop the resulting cycles to stabilise the DC output, something like trailing edge light dimmers still use today. I found that failures tended to occur at particular times of the day but the times were not the same from one day to the next. The common factor was the failures occured when the street lighting turned on, whatever time of the evening that was in the area. That discovery led to questions from the highways people and thats where I found out how all the lights were simultaneously controlled. In fact, they said the biggest problem they had with the system was the opposite effect, SCR power supplies only drew current during positive half cycles and that was upsetting the street lighting!

I think the 'lift' in voltage was probably introduced between earth and neutral, assuming the lighting was wired with a neutral connection, that would allow it to work regardless of which phase powered the light itself. This was many years ago so it is very likely that other, more reliable technologies have since been adopted. TV power supplies have evolved a long way too and I would guess any that gulped half cycles these days would be illegal.

Brian.