Hi,

The 500W halogen light on my drive has just failed for the nth time.

I'd like to save some energy and lamp costs by replacing with a sodium light
of some kind (ideally with a dusk sensor), and on a timer.

Problem is that all the sodium lights I can find are ugly, looking more
appropriate to prison perimeter security or perhaps use on offshore oil
installations.

Example:

http://www.screwfix.com/app/sfd/cat/...12178&ts=07854

....unless anybody knows better. Any suggestions?


David

"vortex2" wrote in message
...
Hi,

The 500W halogen light on my drive has just failed for the nth time.

I'd like to save some energy and lamp costs by replacing with a sodium
light of some kind (ideally with a dusk sensor), and on a timer.

Problem is that all the sodium lights I can find are ugly, looking more
appropriate to prison perimeter security or perhaps use on offshore oil
installations.

You can buy 18W SOX luminaries from your local electrical wholesaler that
will be more than adequate for lighting the average domestic drive. They
look not dissimilar to square bulkhead lights, but mounted horizontally,
with the glass facing down. Personally, I prefer 2 x 9W or 4 x 9W low energy
floodlamps, which have shorter start-up times.

Colin Bignell

vortex2 wrote:

Example:

http://www.screwfix.com/app/sfd/cat/...12178&ts=07854

...unless anybody knows better. Any suggestions?

A little better:

http://www.tlc-direct.co.uk/Main_Ind...ial/index.html


--
Cheers,

John.

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In article ,
"vortex2" writes:
Hi,

The 500W halogen light on my drive has just failed for the nth time.

I'd like to save some energy and lamp costs by replacing with a sodium light
of some kind (ideally with a dusk sensor), and on a timer.

Problem is that all the sodium lights I can find are ugly, looking more
appropriate to prison perimeter security or perhaps use on offshore oil
installations.

Example:

http://www.screwfix.com/app/sfd/cat/...12178&ts=07854

...unless anybody knows better. Any suggestions?

You could use a luminare (fitting) for an ordinary lamp, and
mount the control gear remotely. The easiest way to get all
the bits is probably to buy a luminare like the one you
identified, and then butcher it for parts. If you go this
route, keep the cable between the control gear and the lamp
as short as possible, and beware high voltage pulses are
used to start these lamps (long cable dulls the high voltage
pulse and can cause RFI). Go for a luminare rated in excess
of the power consumption of the lamp (at least 100W, and
preferably 150W) as the sodium lamp will prefer running a
bit cooler than a filament lamp. Any reflectors in the
luminare for use with high pressure discharge lamps must be
of the specular type (as shown in that Screwfix picture),
and not plain polished which can cause arc tubes to overheat
if it reflects the heat back onto them (which is the exact
opposite of what you ideally want for a halogen lamp).

Oh, and these lamps are only suitable for timed and/or dusk
to dawn operation, not PIR (movement) sensors.

--
Andrew Gabriel

In article ,
"nightjar" nightjar@insert my surname here.uk.com writes:

You can buy 18W SOX luminaries from your local electrical wholesaler that
will be more than adequate for lighting the average domestic drive. They
look not dissimilar to square bulkhead lights, but mounted horizontally,
with the glass facing down. Personally, I prefer 2 x 9W or 4 x 9W low energy
floodlamps, which have shorter start-up times.

SOX (low pressure sodium) have a particularly long run-up time,
typically 9 minutes for the larger sizes (never played with the
low power ones, but might be a bit faster because they aren't
as efficient). SON (high pressure sodium) are significantly
faster at around 2 minutes (just measured a 250W one -- 70W is
probably not much different).

Neither is any use if you want instant-on, hence my comment
about PIR usage.

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
.. .
In article ,
"nightjar" nightjar@insert my surname here.uk.com writes:

You can buy 18W SOX luminaries from your local electrical wholesaler that
will be more than adequate for lighting the average domestic drive. They
look not dissimilar to square bulkhead lights, but mounted horizontally,
with the glass facing down. Personally, I prefer 2 x 9W or 4 x 9W low
energy
floodlamps, which have shorter start-up times.

SOX (low pressure sodium) have a particularly long run-up time,
typically 9 minutes for the larger sizes (never played with the
low power ones, but might be a bit faster because they aren't
as efficient). SON (high pressure sodium) are significantly
faster at around 2 minutes (just measured a 250W one -- 70W is
probably not much different).

Neither is any use if you want instant-on, hence my comment
about PIR usage.

--
Andrew Gabriel

What about the colour of the light?

SON is much more appealing (or should I say less unappealing) because it has
a better colour spectrum. See
http://www.lamptech.co.uk/Documents/SO2%20Spectral.htm

To be honest the Screwfix light looks less ugly the more I look at it...and
appears to be a pretty good deal.

David

In article ,
"Vortex" writes:
What about the colour of the light?

SOX is just the two yellow sodium lines, so there's
virtually no colour discernable.

SON is a peachy colour (a sort of very warm white).
The colour is built up up from broadened sodium lines due to
high pressure operation, mixed with mercury lines which is also
present in the arc tube.

Another option is metal halide, which is white, commonly available
as warm white (2700K) suitable for nighttime use, and higher colour
temperatures (4000-5000K) for supplementing daytime light in shop
displays.

Efficiency of these three lamps runs in opposite direction, with
SOX the most efficient (although the small ones less so), and metal
halide least efficient.

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
.. .
In article ,
"nightjar" nightjar@insert my surname here.uk.com writes:

You can buy 18W SOX luminaries from your local electrical wholesaler that
will be more than adequate for lighting the average domestic drive. They
look not dissimilar to square bulkhead lights, but mounted horizontally,
with the glass facing down. Personally, I prefer 2 x 9W or 4 x 9W low
energy
floodlamps, which have shorter start-up times.

SOX (low pressure sodium) have a particularly long run-up time,
typically 9 minutes for the larger sizes (never played with the
low power ones, but might be a bit faster because they aren't
as efficient).

Probably about the same. I have them outside my factories.

SON (high pressure sodium) are significantly
faster at around 2 minutes (just measured a 250W one -- 70W is
probably not much different).

I've never measured them, but you are probably right. I use them as high bay
lights inside one factory, with HF fluorescents on the same circuits to
provide some instant light at switch-on.

Neither is any use if you want instant-on, hence my comment
about PIR usage.

The OP's suggestion of a dusk sensor and timer suggests that instant-on is
not important.

Colin Bignell