AC power adapter grounding

"spamtrap1888"

I noticed in Germany that the bathroom light switches are outside the bathroom.

** Ah, this is because the Germans are so fond of pranks.

Turning off the light when someone is having a bath or taking a dump is HILARIOUS !!

It is even funnier when a young lady is taking a bath, because she will have to appear outside to turn the light back on.

What happens if she cannot find her towel in the dark ?

Answer: Germans ROTFL.

... Phil

Reply to
Phil Allison
Loading thread data ...

What is a "DC dongle adapter"? Because I've never seen an AC power adapter that didn't contain an isolation transformer, so is a dongle adapter something different?

A Class II double insulated drill isn't required to have all its exposed metal isolated with double insulation, and usually the front 1/4 of the case is an aluminum casting that the user often holds during operation, and inside the casting are gears that come into contact with the motor's metal shaft. So if there's a breakdown in the motor's insulation, where's the benefit of the double insulation here? OTOH an AC power adapter's isolation transformer is supposed to protect against high voltage leakage to any exposed metal.

Reply to
larrymoencurly

** Fraid that is not so.

All exposed metal must have "double insulation" between it and live parts - and that insulation must stand up to foreseeable events like the motor windings burning.

** Generally there is a plastic coupling or gear wheel to isolate the head of a class 2 drill.

Methods that prevent the windings in the drills motor from ever overheating are also possible.

** You are inventing stuff.

** And does so very nicely under nearly all conditions.

Salt water bath not withstanding, as I already pointed out.

Some folk are incapable on comprehending the benefits of Class 2 insulation.

Like the f****it OP here.

... Phil

Reply to
Phil Allison

Putting a switch on the outside works. Putting an outside switch on a bedroom does not work out.

Greg

Reply to
gregz

Yikes. In the colonies, we can mix and match up to the maximum rating of the breaker panel. For example, if I have a 200 amp breaker box, I can install a mixture of breakers that total 200 amps or less. Mostly that's 15A circuits for the wall plugs and 25A for the major appliances, within the wire gauge and length limits. 32A on a single circuit wouldn't work very well here.

Killed by the safety equipment? What else is new? I've been ranting about how many safety features and devices are actually more dangerous that whatever they're trying to protect because of user complacency.

Sticker shock? No whole house GFCI systems for the empire? I had one for about a month and got fed up tripping it by accident. It was so sensitive, that when I plugged in a device that has two capacitors between the lines and ground, the differential leakage (usually dirt on the capacitor case) was sufficient to trip the GFCI. Also, the fridge had an irritating habit of tripping the GFCI. I sold it last year, but plan to try again with individual GFCI outlets. At $5/ea, they're cheap enough.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
 Click to see the full signature
Reply to
Jeff Liebermann

"Jeff Liebermann" "Phil Allison"

** In the UK, most AC outlets operate from a " ring mains" - which means that a heavy gauge, 3 core cable is connected to the AC supply panel at BOTH ends.

This minimises voltage drops and makes the 32 amp rating practical.

I guess this means that most stoves, water heaters and the like can simply plug-in rather than always needing dedicated AC circuits.

See pic of the very chunky " 13amp " UK plug:

formatting link

and with a fuse fitted:

formatting link

.... Phil

Reply to
Phil Allison

Yeah, I can imagine, especially with kids in the house.

One of my customers has little too much money and likes to spend it on gadgets. His latest buy was an assortment of Z-wave devices:

to control the lights, fans, vents, etc in his house. What's nice is that most of the controllers use energy scavenging and do NOT require a battery. The controller can be stuck anywhere. If you want the bathroom light switch in the kitchen, easily done. It's also a mesh network. Given enough AC powered devices, controllers will work anywhere in the house without additional wiring or repeaters.

Of course, prices are high:

$25 for a wall switch dimmer controller. Ouch. However, with one these, you could have a switch both inside and outside the bathroom.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
 Click to see the full signature
Reply to
Jeff Liebermann

Yeah, that works. We have a star arrangement here, with the option to add sub-panels to expand the star. Fuses are all at the breaker panel. The system will not prevent someone from being electrocuted, but usually adequate to prevent an electrical fire from a short.

I would think that it would be difficult to install a whole house GFCI box on a "ring mains" wiring scheme. Oh, no wonder I couldn't find it. It's called an RCD in UK.

Ummm... yeah, that's messy and very different from US wiring.

Maybe. Most of the US high current appliances use 220vAC while the lower power stuff runs off 117VAC.

Counterfeit BS 1363 plug:

Nice video. The US plugs will overheat, melt, sometimes catch fire, but rarely explode.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
 Click to see the full signature
Reply to
Jeff Liebermann
[snip]

Most do. SMPS wall warts/adapters have transformers that operate at high frequencies rather than 50/60 Hz. But they are transformers with the same isolating properties nevertheless.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
 Click to see the full signature
Reply to
Paul Hovnanian P.E.

Is there another way to get Galvanic Isolation in a power device? Rather than a signal device.

--
John G
Reply to
John G

"John G"

** You could use a heating element and Peltier cells to get DC from the AC supply.

But that technology is more appropriate to Mars rovers ....

..... Phil

Reply to
Phil Allison

My old Sears Craftsman consumer grade double insulated drill measured from about 20-1800 ohms whem measured between the rear of the motor shaft and the chuck, depending on how hard I pressed a piece of copper wire against the shaft or rear bearing. The resistance between the chuck and aluminum housing at the front was about zero ohms. Here's a photo:

formatting link

We had a Eureka vacuum with a steel housing and 2-wire AC cord, and that cord was sliced all the way through its insulation in a few places by sharp edges on the cord reel.

I'm not worried about being shocked through the plastic but through exposed metal on the computer connected to an ungrounded AC adapter that isn't safety certified by UL or CSA.

Reply to
larrymoencurly

But you never checked the standard of the complying insulation between the Electics and all the metal parts you found were connected together.

And who said it was double insulated anyway? I cannot see a double insulated standard mark on the name plate.

--
John G
Reply to
John G

"John G"

** The FW would not even know what to look for.
** " DOUBLE INSULATED " is written on the name plate.

It also carries the UL logo, so it seems kosher.

WARNING:

Do no get ambushed by an individual example that YOU cannot investigate.

If somehow the drill fails to actually meet class 2 requirements, that is NOT a reflection on the standards.

.... Phil

Reply to
Phil Allison

Phil Allison formulated the question :

Of course you are correct. I was looking for the Symbol and missed the wording (age has its dificulties). As he says "His Old ...." may predate the standard symbol.

Absolutely.

--
John G
Reply to
John G

That's because all the sockets are on a single ring circuit, with a single

30 amp breaker for the lot.

Adopted after WWII because of copper shortages.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
 Click to see the full signature
Reply to
Fred Abse

Just in case it was a fluke for the first drill to measure 20+ ohms from chuck to shaft, here's another drill, made by One World Technologies, the producer of many Ryobi handheld tools:

formatting link

The meter read 4.7 ohms. I saw no electrical isolator between the metal shaft and gearbox (visible gears were metal) or between the gearbox and chuck. I had to remove the plastic cover to measure the resistance.

Reply to
larrymoencurly

Current transformers sitting on some high voltage lines are sometimes powered by a high power laser feeding a fibre up to the measuring device and an other very low power fiber is used to send back the measured value.

Reply to
upsidedown

** READ what I wrote- FUCKHEAD !!

" ** Generally there is a plastic coupling or gear wheel to isolate the head of a class 2 drill.

Methods that prevent the windings in the drills motor from ever overheating are also possible. "

Reply to
Phil Allison

Not in the only two consumer grade double insulated drills I checked, including a drill from one of the leading makers of handheld power tools.

Is it inherent protection, or does it require a high temperature cutoff? Some Sears drills and vacuum cleaners included a bimetal switch on the motor that would open when overheated, while almost the same models sold by other companies lacked that.

Reply to
Bob Boblaw

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.