View Single Post
  #7   Report Post  
Falky foo
 
Posts: n/a
Default

Thank again guys!


"K. Smith" wrote in message
...
Falky foo wrote:
Hey, thanks much for all the help recently. I want to replace the

bare-bulb
interior bulkhead lights on my 25' sailboat. So I took one off today

and
looked in it and it said it was rated for up to 220 volts. Does this

mean I
can go out and buy cheap Target fixtures and install 12v bulbs in 'em

and
they'll work? West Marine's fixtures cost about about 5 times more than
they're worth it seems to me. Thanks again!




Yes it does mean that but like most things;-) be a little careful of
any related wiring/switches etc the 220 volt light may already have.

The volt rating just refers to the insulation ability of the
wiring/switches etc (volts=pressure) not the load carry ability of the
wiring (amps=flow/volume).

To get a reasonable amount of light out of 12 volts you'll need
probably 12-15 watt bulbs as a bare minimum which is 1-1.25 amps.

A normal 220 volt lamp with say a 60 watt bulb is only drawing about
0.25 amps.

So you can see that the very small but well insulated wiring etc within
the lamp may be over loaded & get hot if subjected to a sustained load
of 4 to 6 times the designed intention, even though it's only @ 12 volts.

Being aware of the issue you can choose a lamp which minimises the
problem or you can rewire it with heavier gauge wire if you like.

There are some 12 volt lights about 2" in diam used as spot lights or
feature lights in shops but also houses etc, they come with a
transformer for domestic mains use. They are popular on boats, plastic
(no corrosion) exceedingly cheap, very very bright (4 amps) & save you
handle it, have a long life tungsten globe. You can buy just the globe
it comes with the reflector as part of it & just mount it where ever.


K