[SML] Ratings of household lighting fixtures

[e-mail frank.wood95]

> 
>     On 22 September 2015 at 15:35 Jon Ares via Stagecraft
> <stagecraft at theatrical.net> wrote:
> 
> 
>     This can be considered 'on-topic,' I believe.... does anyone know
>     (more or less definitively) how manufacturers come up with the
>     "ratings" for table lamps, desk lamps, pendant lights, etc... when
>     they say "Max. 60w" and such....? Are these based on presumed heat
>     dissipation, or on any sort of amperage tolerance of the socket,
>     or....?
> 
>     I was wondering about this, as we have several different choices
>     beyond incandescent lamps now... each with different power draws, heat
>     management systems, etc.... I wast thinking it would be nice to know
>     how these ratings came about, when determining if it's OK to put a
>     lamp with greater lumens than that A-style 60w bulb, but may only draw
> 

I too have wondered about this. I have, hitherto, assumed that these ratings
were predicated on a normal incandescent bulb, and its heat output. But with
modern high effiency bulbs, such as the halogen substitutes or CFLs. I still
assume that the heat output is related to the power consumption.

I am sure that it relates to the internal wiring, connections, and so forth. In
the UK, bayonet fittings are ususal, rather than the ES fittings used elsewhere.
I have sometimes found that the solder contacts on the lamp bases have softened
over the years, allowing the spring contacts to indent themselves in the solder
pads, which has made the dead bulbs difficult to extract. Some brands of GX9.5
bases are very prone to overheating problems.

Heat management is certainly a serious problem with lighting fixtures. I have
heard it said that you can make toast on the heat sinks on some Selecon
luminaires. Any way, running light fixtures beyong their manufacturer's ratings,
however derived, is not sensible.
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