On Thu, 2 Dec 2004 00:27:15 +0200, "Risto Tiilikainen"
wrote:



Fail safe? How do you figure?

Thanks for your comments to the various questions.

Maybe my English impression was poor.
With fail safe I was meaning the safe construction which is controlled by
regulations and paragraphs.
In outdoor use and in moist places standard fluorescent tubes, their wiring,
chokes and igniter are never allowed to have open construction. (at least
here in Nordic countries)
Similar situation is not with neon lights on the walls. Sometimes there are
bare without any enclosures.
I even remember having seen the end wires of the tubes visible.
Well - normally neon lights are rather high so that people cannot touch
them.

Risto

Interesting. I'd probably call what you refer to as "fail safe" as
"foolproof."

Do you have stricter regulations regarding fluorescent lamps versus
other line operated electrical appliances?

Perhaps the reason for stricter controls is the fact that fluorescent
lamps are frequently used in family residences.

Or, perhaps they are concerned about electromagnetic fields - here it
is politically unpopular to even hint that low frequency emf's can be
damaging to health. I've read that some Scandinavian countries are
considering imposing LF EMF limits or are already doing so. Do you
know anything about that?

I see the same things with neon tubes here, particularly in the older
establishments. Wires with just a plastic or glass sleeve over the
connection to the tubes and not protected from water or hands.

The transformers usually have a secondary center tap that is grounded,
so each side of the neon tube only sees half the total high voltage.
But half is still a lot . . . My smaller transformer is 10 KV @ 30 ma
(for ignition on an oil furnace - but identical in construction to a
NST). I can't imagine it feels good if one were to get body parts
across it. It is designed to start fires . . . I'm not about to try
it and I don't know anyone who got shocked by one.

One correction to my earlier post: The common style of car ignition
transformer relies on a rapidly collapsing magnetic field to produce a
spike of high voltage, not just the turns ratio. Field builds slowly
and collapses fast.

If the same induction coil were used with a capacitive discharge
ignition circuit, the turns ratio and high primary voltage produces
the high voltage.