However, the big problem with switching hot and cold (aside from the surprise you’re leaving for some fool twenty years later who goes to do some wiring and assumes, being the idiot that he is, that the previous lunkhead did everything correctly) is what happens if you combine it with something that switches neutral and ground. Making those two swaps in series means that effectively you’ve now got the hot wire switched with ground. Not recommended. The safe half of it is the part about hooking the household ground (which around here is normally wired to the incoming cold water pipe) up to the appliance’s hot power wire, which will not effectively power your appliance but also will not do any tremendous harm, at least under normal circumstances. The less safe half of making that switch, though, is that the household hot/active is wired up to the appliance’s ground. A lot of appliances run the ground wire to the chassis or metal case. So touching the appliance in such a situation connects your personal body to the full voltage. Extra bonus points if you are standing barefoot on a metal heating/cooling register at the time, or otherwise touching anything that’s grounded (such as, for instance, a correctly-wired appliance). Now the AC voltage from the household hot power line is connected to the neutral line on the extension cord and thence to the ground line of the appliance cord, to the chassis of the appliance, to you, and from you to the chassis of the other, correctly-wired appliance that your other hand is touching, which is wired to the household ground. Congratulations, you are now a conductor.

I am pleased to live in a country where that’s normally 110V/60Hz for most wiring. Getting jolted with that is not a comfortable experience, as I can personally attest, but unless you have some kind of heart problem or something it will usually not cause any lasting injury to an adult. Not that I suggest doing it on purpose or anything.

220V is more worrisome. I know a guy who inadvertently brushed up against a range cable while working in home construction. That’s 220V/60Hz, and it left black fang-marks on his arm where the two wires touched him. (I *think* it was a surface burn, so not permanent. Still. And he was lucky in that he brushed against it only quite briefly.) Australia and most of Europe, I am given to understand, operate nearly everything, even lights, at 220V. There are various arguments for and against the higher voltage (the most important of which, in most areas, is backward compatibility with existing infrastructure and appliances), but from a safety perspective I know which I’d rather get shocked with.

Pleb: “I want an adaptor”
Sales staff: “What kind of an adaptor”
Pleb: “You know, an adaptor?” (Pleb now looks at sales staff like he/she is bereft of their senses)
Sales staff: “What exactly were you seeking to adapt?” (Sales staff is now clenching his/her fists so tightly their knuckles are white)
Pleb: “A plug.”
Sales staff: “Excellent. What kind of plug?”
Pleb: “Oh. A power plug.”
Sales staff: “Ah, well you didn’t say that at first did you? They’re over there.”
Pleb: “TEN BUCKS!@#@!#!@#!@ CANT I JUST MAKE ONE MYSELF?”
Sales staff: “Yes but that would be illegal.”
Pleb: “Can’t you do it?”
Sales staff: “Yes that would be even more illegal, and I’d be awfully tempted to bridge active, neutral and earth together and see just how much your hotel really appreciates your business.”

Then they leave with their “adaptor”. The best ones though are the middle eastern males who absolutely refuse not to rewire all their appliances themselves and look about ready to punch you in the face when you inform them that even if you wanted to it’s against company policy for you to do it for them.

Needless to say the “I want an adaptor” customer is the bane of every DSE employee’s existance and while it was a little off topic I saw that comment by Dan and just HAD to throw my two cents in.

A while back some network technicians were requested to install two jacks in a floor tank in a restricted area at work, and I was given the task of supervising them. Having just run some Cat5 at home and made a mess of it, I told the guys I was looking forward to seeing how professionals did it. What happened over the next couple of hours left me speechless.

- One technician removed floor-tiles around the edge of the room and got the cable laid there. Then he discovered that the tiles were wedge-shaped (it’s a circular room), and the tiles would only fit in the right order/orientation. He spent one hour getting these back in.

- The other technician pushed a wire-puller down through a conduit under the floor, but was unable to get it to come out the other end. He was also unable to get the tool back out of the conduit, so he ended up sticking the other end into another conduit, and getting that stuck too. At some point in time he managed to get cable pulled through the conduit, but one conduit was still blocked with the cable-puller. He eventually decided to leave it there, and cut it off under the floor. As he cut the fibre-glass rod, sparks fly out of the floor-tank (there’re power-points in there too). Not sure where those came from, but as the power sockets are labelled, I check the breaker and it looks okay.

- Having got the cable run, the two team up to install the jacks. But the sockets they have are a different system to what we’ve got in our tanks. So they set about trying to get this thing installed anyway. They come up with a workable solution, and one goes off to find a battery-drill. Half an hour later he comes back with a drill-bit, but no drill. Proceeds to try to drill holes in hard plastic with nothing but a 4mm drill bit in his fingers. The other decides to cut up a bit of the tank’s existing mounting-plates so that his network sockets will fit in there. This is accomplished with a hack-saw, and much bending back-and-forth of the plate. The result is bent, covered in blood (he cut himself while bending the metal), and the network socket still doesn’t fit into it.

After two hours they got the tank together and we had to vacate the room. The rest of the work (running the cables to the patch bay) was to be done in a patch-room outside of the restricted area, and was done a few days later, once they’d found the key to the patch-room. Of course, they did it when I wasn’t around, and so couldn’t test the result. A few days later, a user went to use the sockets and found that not only did they not work, but also the power-points in the floor-tank were dead.

Professionals…

Well. Without fail, at least once a week (very often more) we get to play this cryptic game of 20 questions:

You’re looking for a ‘plug adpter.’ Okay, what kind of plug? An electric plug? (In lower class America, nothing is electrical, electronic, or electricity. It’s all “electric.” As in ‘Hey, the electric is out.’ It makes me want to punch people, but then again so many things do. I digress.) Yes, I assumed that. What are you adapting from and to? The thingy that you put into the socket to another one just like it?

Ah, now you see the game. What homeboy is looking for (though homeboy is seldom articulate enough to express it the first five or six tries) is a male-to-male 120 volt mains adapter (Sometimes female-to-female; yes, mains power in the USA is a wimpy 120 volts).

The sob story usually goes something along the lines of Husband starting on one end of the house Wife starting from the other, no coordination between the two, and they meet at the middle both holding identical plugs. Fit together they do not.

Of course, the niggling fact that there is a very good reason such a thing doesn’t exist (plugging a duplex outlet into itself with an extension cord is the first the leaps to mind…) isn’t the customer’s fault, it’s OUR fault, and without fail are we railed on about our inadequacy of not stocking such an item.

Usually I have to explain why very slowly, using small words and simple expressions (electrocution BAD!) to get the point across, and ultimately am forced to give up. See, you’re the kind of customer who would already know how to build your own, so I could leave you to it.

I did once make a male-to-male adapter out of two plugs and about six inches of extension cord wire for a regular customer who I had reasonably confidence would not do anything stupid with it. He ran a local towing/auto repair sort of place, and had a christmas light display in his yard utilizing some hundred-and-fifty-thousand bulbs that was basically a local tourist attraction. It’s made the papers on several occasions; I don’t think he’s burnt his house or display down since I built him that adapter.

1a. I think that you can do the work if it is checked/supervised by a qualified electrician.

2. Having any electrical work performed by an unlicenced party can make your home and contents insurance null and void. The burden of proof is probably on the householder, check your policy.

3. I had a lecturer at uni who designed one of Japan’s biggest power plants. I always found it amusing that he was not allowed to change his plugs or sockets.

4. The mere thought of the mouth-breathers that I meet doing their own electrical work scares the bejesus out of me. Especially when you consider the mess properly licenced people can make.

5. Most of the world lets you change your own plugs and socket. Some say that the Australian laws are in place to protect the jobs of electricians.

6. If doing this is so wrong, why can we still buy the plugs and sockets? I’ve always been confused by that. You can legally by the components, but you can’t use them.

Guess I’m just happy that the week’s over at last…

Other devices which only have single-pole power switches may unexpectedly have live power in them if connected the wrong way around, but that should normally only be of concern to people who poke around inside them. :) I can imagine situations where always having a high potential on an electronic component might have some unexpected side-effects, but what would I know.

Some european countries have polarised domestic plugs and sockets, some don’t. I have no idea what the regulations are for devices sold in the EU, but that probably shouldn’t make any difference to how you work with equipment - if you assume that any exposed electrical conductor is live until proven otherwise, then you’ll stay alive. :)

I can’t imagine any electrical device being wired so badly that an unexpectedly reversed AC polarity would cause the case of a device to be live, but anything’s possible! When buying an electrical product I personally never check whether it’s been certified by the TUV (or similar), but I guess there are safety regulations regarding such things, and now we all now why. :)

I haven’t lived in Oz for a while now - guess it’s fair enough that some things have changed in the meantime. ;)

I lived in Ireland for a short while, and it seemed to be pretty common for people in the funny-language-tech-support community to hack their own adapters so they could plug in their own European hardware. I have seen some reasonable hacks; and I have seen people just forcing their plugs into extension cords and using a spoon jammed into the ground hole to get it all to work. (Something needs to be plugged in there to basically open a switch.)

It seems this wouldn’t be that bad (if done right), but if it is possible to “kill yo’ ass dead” by reversing the wires, I wouldn’t want to be in the opposite situation, plugging in UK/AU appliances into a European socket.

So matt, Dan; is it actually common having things that expect active and neutral to be in their correct places in countries that provide for a distinction? Because that scares me a little.