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From: email@example.com (Bob Wilson)
Subject: Re: Wall wart with two blade polarized plug,,,Why?
Date: Sat, 05 Oct 2002 03:47:39 -0000
Organization: Your Organization
X-Newsreader: WinVN 0.99.9 (Released Version) (x86 32bit)
In article , firstname.lastname@example.org
>"Patrick Timlin" wrote in message
>> Jeff Wisnia wrote ...
>> > I'm trying to think of a realistic reason why my little TV's 120 vac -
>> > 12 vdc 1.0 amp simple xformer/bridge rectifier wall wart needs one of
>> > its two input blades wider than the other so that it won't insert into
>> > an duplex outlet in a convenient direction. (i.e. so its body doesn't
>> > interfere with a right angle cord plug already in the other half of the
>> > outlet.)
>> I can only think of two reasons. One, and the most likely, is they
>> just did it that way for no other reason than the "prong kits" they
>> bought came like that.
>> The other is the more unlikely chance that the transformer is not an
>> isolated transformer (with primary and secondary coils) but instead an
>> auto transformer (single coil with a tap off for the lower voltage
> ** 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 reason
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 is
plastic. There is NOTHING to ground!". His response? "Oh! I never thought
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 have
forced the manufacturer to make the drill double insulared, and
intrinsically safe. Now you say that the polarized plug is needed. Are you
telling me that you don't trust your own safety standards?". Much
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