22 Mar
2004
22 Mar
'04
1:50 p.m.
> Well, here you pretty much have to break both,
even if one is
> neutral sometimes. Much better than having a "half hot" circuit.
I'd think that care for disconnecting all possible
'hots' coming into
the chassis is more important on most things... excepting perhaps
cheap things like lamps
It can be important there too. I've been bitten a few times by shocks
from devices with two-wire cords when some physical
fault has let one
wire leak to a metal chassis and the plug happens to have been
plugged
in the wrong way around, so that the wire the device is designed to
treat as neutral is actually the hot, and the power switch is in the
lead that's actually neutral.
Even since the advent of the polarized two-prong plug this is a real
risk; "cheap things like lamps" are common targets for plug (and
sometimes entire cord) replacement - and the sort of screw-terminal
mains plug sold in small quantity to weekend bricoleurs is almost never
polarized, and most of the amateurs doing such replacement I wouldn't
trust to get it right if it were. (Heck, I wouldn't trust _me_ to get
it right from memory - I can never remember whether the wide blade is
hot or neutral; I have to test an outlet.)
or things designed to only work with a hot/neutral
setup, like a 120V
"surge protector."
Things like that usually use grounded plugs anyway. At least here in
North America (which is where you'd find 120V mains devices anyway).
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