leaving conductors exposed

I'd guess because 20 volt AC is considered safe. A 20 volt AC power supply could also have output terminals etc which wouldn't conform to mains etc voltages. The 'double insulation' is to help prevent mains appearing on parts you can touch easily.

BTW, it's more likely to be approx 12v under load.

Because humans aren't likely to be electrocuted by 20V, AC or DC.

But this does raise a question... What about insulation between the primary and secondary windings? Its failure could put line voltage on the secondary.

Depends on transformer design - assuming it does use one.

Ok, but how did it make it past the "fire hazard" category. It's surely a source of ignition when you knock it over onto a pair of scissors on the desk.

Methinks the inspector was either asleep or out cruising in the Beemer he bought with the payoffs.

A fuse somewhere?

Think you're worrying too much.

There are high isolation transformers with the windings on separate bobbins. The efficiency is lower than traditional overlaid winding, but the two windings aren't close enough for anything less than a lightning strike from reaching the secondary and there isn't any design that is safe from a direct strike.

that's if you believe the markings on the product in the first place.

Can you measure the leakage from either of the antennae to ground?

Indeed. Often called 'medical quality'.

"mike"

Most often this is achieved by adding a thermal fuse to the primary circuit that will open if the winding temp reaches a point that could damage the insulation used to make the tranny - about 120C in most examples.

Some older designs used fireproof insulation between the primary and secondary and the winding were contained on separate halves of a plastic bobbin. Such a tranny could smoke and burn but still not present an electrocution hazard.

.... Phil

"Cydrome Leader"

In this case however, the presence of a "one shot " thermal fuse in the primary winding of the AC tranny will do the job ALONG with split bobbin construction.

.... Phil

Ok, but what about the spark that happens when you knock it over while refilling your butane torch? Or when you just cleaned a part with alcohol. Dumb design!!! Safety design is a LOT more than just the obvious. There'd be a lot fewer houses burned to the ground if only engineers thought more about how their products are used and the hazards caused by confluence of circumstance. Did I mention...DUMB DESIGN!!

I nominate you for a Darwin Award. The timing is up to you.

"mike"

.... Phil

At least don't fart if you do.

There was a guy in the steel mill I worked at (in the office) who was killed by his table radio, iirc, It's a little rough in the mills, the computer monitors and keyboards got very dirty, but I'm still surprised the radio killed him.. After that, they wouldn't let us use any radio or fan unless it had a 3-prong plug (and presumably 3 wires, one of them grounding the chassis. I was a contractor and wan't going to play games by pretending to have a grounded appliance when I didn't, so I gave up on the fan and brought in a transistor radio.)

As to the risk here, I routinely touch both clips of the 1-amp 12 votl battery charger I have. I havent' done that with the 8 amp charger, probably because the phrase "8 amp" scares me, but it shoudln't and tomorrow I will, I'll even find some alcohol to spark in. If I don't post back, it means my house burned down and took my computer and me with it.

It only takes a few milliamps to kill you. Assuming the current has a path to a vital organ, like the heart.

Of course many modern car battery chargers have a relay on their output with the coil operated by the battery - via a diode - to prevent damage to the charger if it's connected with the wrong polarity. Which also means it's less likely you'll touch the connectors when they're live.

A powered up but disconnected battery charger of a basic design might well present a greater 'hazard' than when connected to the battery as the open circuit voltage could be much higher than the nominal 12 volts.

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But you bought a chinese no name "design" lamp, with chinese construction "quality" and chinese design "aspect" and you pretend that this lamp should be properly designed??? I bet you that the creator of that "jewel" isn=B4t even an engineer.

If you don=B4t fell comfortable with the lamp, and I wouldn=B4t BTW, just trash it.

n't

=A0 London SW

Certainly you can be killed with a few milliamps, but only if the voltage is 60V or higher.

Current flow depends on resistance as well as voltage. And when talking about the human body that resistance will vary by a huge amount depending on many factors.