In article ,
Fred writes:
Hi,

Whilst helping the relatives have a spring-clean, I found an old
exterior light, it is rather like a street lamp, so more
commercial/industrial than domestic. It looks as thought the fitting
is largely made of aluminium, so I was hoping to take it to the scrap
man.

I think they may be sodium lamps as the bulbs look something like a BC
version of this:
http://www.screwfix.com/p/sylvania-h...ges-250w/90688

The shape is a standard equi-thermal bulb (the shape you end
up with if you want the bulb to be similar temperature all
around the enclosed short arc tube, ignoring convection heating).

I've never seen a BC high pressure sodium lamp, or BC on any
equi-thermal bulb, because a BC lampholder can only support
that weight and size of lamp when hanging cap-up. It was used
for some early mercury vapour lamps with more conventional
(GLS/pear-shaped) lamps, for use in cap-up fittings, including
self-ballasted ones with internal filament ballasts, but yours
has an external ballast (and no external ignitor, at least, you
didn't mention one).

BC is also used for low pressure sodium lamps, but the lamp
has an additional bulb support in this case, being long
tubular in shape, and (almost) clear glass.

So it would be interesting to know all the markings on the
lamp, and a picture, and same for the ballast, and lantern.

I notice the description says "golden white" whatever than is! I
thought they were orange.

Sodium can be anything from orange through to warm white,
depending on the arc tube operating pressure and other doped
elements included.

Inside the fitting is a large (in terms of size, not capacitance)
capacitor and a heavy metal ballast. The ballast is a sealed unit.
Does it have an iron core? Is that why it is so heavy? I'm just
wondering what bag to throw it into to take to the scrap yard. Do I
throw it in with all the steel? Perhaps I should angle grind it open
to see what's inside?

It probably has more resale value than scrap value.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]