"ARWadsworth" wrote in message ...
Andy Wade wrote:
On 18/04/2011 08:30, The Medway Handyman wrote:

Using a dimmer switch on your lights at home doesn't save very much
in electricity AFAIK, e.g. dimming to half the light doesn't reduce
the power consumption by 50% - is it different on street lights?

Yes, because you're dimming a sodium discharge lamp, not a tungsten
filament. With tungsten the lumens per watt efficacy drops
dramatically when you under-run the lamp. With a discharge lamp it
may still fall off, but to a much lesser extent.

Dimming is not new. The street lights in the road where I live were
replaced a couple of years ago. After midnight they dim to 75%
output, or so the letter from the council said.

'Intelligent' street light control seems to be becoming a large
industry, e.g. http://www.e-streetlight.com/

There was an LED street light outside a house I worked at last month.

They must be cheap to run, but not cheap to install. The odd thing is it was the only LED street light there. The rest were
discharge lamps (and new ones as they stood next to the old concrete streetlamps)

--
Adam

Was the light from it steady or strobed?

--
Graham.

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