[Amps] More on two pin 220vac

[Manfred Mornhinweg]

I can't help but contribute my own wisdom to this thread, too!

In Chile, in ancient times, we had 220V with two-pin outlets. I don't 
know exactly when the standards were changed to include ground, but I 
know for sure that homes built in the 1950s had those two-pin outlets, 
and that in the early 1970s some devices showed up with those "strange", 
new-fangled three contact plugs, that couldn't be plugged into the 
"normal" two-hole outlets, and people massively solved this in the 
Chilean way: They cut off the ground pin of the male plugs! And worse: 
Some plugs allows the ground pin to be simply removed by unscrewing it. 
That left the ground wire inside the plug moving around freely, often 
shorting to one of the other wires!

I think that around 1970 the standard must have changed here.

All current electrical installations here have 3-contact outlets, with 
ground at the center pin, neutral on one side, and a 220V phase on the 
other side. These outlets are non-polarized, so that inside the 
equipment there is no way to make sure which pole is phase and which is 
neutral. It changes when the plug is turned around.

Now what I wanted to say: There is nothing wrong, really, with 
two-contact outlets. An electrical distribution system without ground, 
using two-contact outlets, can be safe and sound, as long as ALL devices 
plugged into those outlets are designed for non-grounded operation! That 
means that these devices either must have non-conductive outsides, or if 
they have any metal exposed to the outside, this must be doubly 
insulated from the line. When these conditions are met, ground is 
neither required nor even useful!

The only reason to have ground available in the outlets is to allow the 
use of singly insulated devices that have metal parts exposed. These 
need to have the ground connected to those metal parts, to meet safety 
standards. So, three-pole outlets provide more flexibility as to how 
safety is achieved in each device.

In countries that are in the transition between two-pole and three-pole 
outlets, the rules one should follow are these:

- Two pole outlets are fine, as long as they don't allow insertion of 
three-pole plugs. This limits their usability by excluding devices using 
3-contact plugs, but many devices have two-pin plugs and just don't use 
ground anyway.

- Three pole outlets are better, but they MUST have the ground contact 
actually grounded. A three-contact outlet with the "ground" contact not 
grounded is a trap.

- Any sort of adapters that allow connecting three pole plugs to two 
pole outlets, like the mentioned outlet strips, are unsafe and must not 
be used.

- Equipment that has three pole plugs must only be used with three pole 
outlets. Applying the old Chilean method of cutting off the ground pin 
is forbidden.

And a final note: The real importance of all this is not that big! Even 
with gross and massive, widespread violation of these rules, as it was 
common in Chile in the 1970s and early 1980s, there must have been very 
few electrocutions due to this. I actually never heard of any! I grew up 
in the time of change here. In my parent's home, when I was a kid, there 
were many devices that came with three pin plugs, of which we cut off 
the ground pins, or used non-compliant but widely available three pin to 
two pin adapters. Among them the fridge and the washing machine. The 
fridge had poor insulation somewhere, or high capacitance between motor 
windings and the housing, I don't know. It gave a mighty tingle when 
touching it, and when stretching out our arms, touching the fridge with 
one hand and the water faucet with the other, the tingle was 
particularly intense. We played with that, with my friends. Who could 
endure it for a longer time. And we survived!

Of course that was just a small fault current, but I was shocked by 
direct 220V, even hand-to-hand, many times. Many T adapters (to connect 
three devices to one outlet) were shaped in such a way that it was 
perfectly possible to insert just one pin of the plug, and leave the 
other pin exposed to the touch. One could easily get shocked that way. 
That really hurt, but I never had any lasting damage from it - except 
perhaps developing a tendency to bore everyone with long postings!

Manfred

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