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From: email@example.com (Bob Wilson)
Subject: Re: Wall wart with two blade polarized plug,,,Why?
Date: Sun, 06 Oct 2002 05:10:16 -0000
Organization: Your Organization
X-Newsreader: WinVN 0.99.9 (Released Version) (x86 32bit)
References: <3D9A856D.99A017C7@110.net> <3Dun9.firstname.lastname@example.org>
In article <3Dun9.email@example.com>, firstname.lastname@example.org
>"Bob Wilson" wrote in message
>> In article ,
>> > ** Wall warts with DC output are NEVER auto- transformers. That
>> >would, be extremely dangerous.
>> > .. . . . . . .Phil
>> Some years ago, I asked a similar question to a CSA guy. The Wall Wart in
>> question actually had a 3rd ground pin. I asked what on earth was the
>> for this. He said it was necessary to endure a safety ground. So I asked
>> "Precisely WHAT is it that is being grounded? After all, the transformer
>> itself had to be certified for its isolation, and the wall wart housing
>> plastic. There is NOTHING to ground!". His response? "Oh! I never thought
>> about that!"
> ** The ( unconnected) earth pin is often included for a more secure
>fit in the outlet - so the wart will not easily dislodge.
>> I then asked why my Bosch hand drill that was CSA/UL certified as "double
>> insulated" had to have a 2-prong polarized plug. He said it was to ensure
>> the correct part of the drill was connected to neutral. So I said "You
>> forced the manufacturer to make the drill double insulared, and
>> intrinsically safe. Now you say that the polarized plug is needed. Are
>> telling me that you don't trust your own safety standards?". Much
>> backpedalling ensued!
> ** Well - it is nice if the switch is in the active and not the
>neutral. All Aussie plugs are polarised - we have two flat but angled-in
>pins for A and N and a slightly longer one for ground. It can only go in
>one way even if there is no ground pin fittd to the plug.
> Regards, Phil
What is particularly intersting here, is that the standard Schuko plug is
used nearly everywhere in Europe, and it has no polarity. Nonetheless, there
are no documented safety problems related to "polarity reversal' there (the
Schuko is also a far safer plug in other respects as well).
So I find it interesting the regulatory agencies in North America (and other
places as well) seem so anal about an issue (polararity reversal) that seems
not to be a problem in the first place (if one is to judge by the European
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