On Sat, 11 Dec 2010 06:15:24 -0800 (PST), s wrote:

i got a desk lamp from ebay like the one in the image link below. the
bulb is held up by two adjustable telescopic rods, exactly the same
type as you would find on the aerial of a FM radio. they are metal.

i saw the double insulated symbol on the bottom, which go me thinking.
how did they get the wiring through these rods double insulated, they
are pretty thin. then i examined the rods. they had joints in them.
they werent even hollow! there was no wiring. they were the
conductors.

a quick check with the meter gave 20V AC. thats how it was designed
to light the bulb .

my question is can you have the double insulated symbol on a product
with exposed 20V AC conductors?



http://www.flickr.com/photos/31506127@N03/3033028166

The transformer isolates the bulb powewr from line power and ground.
At 20 volts it is still considered"low voltage" and "intrinsically
safe"