220v air conditioning outlet - which wire is hot?

I am assuming that the rounded prong is the ground but I don’t know which of the flat prongs are the hot and which isn’t? Any help? I am installing a plug on the electric oven that I brought from the mainland. It is all electric, not electric - I think even the timer is not electronic, if that makes any differnce.

That would be the one that shocks the shit out of you.

I would avoid red but what the hell! I can’t even understand whch button to push on the toilet.

I’d rather give you the number of the nearest shuidien han or general repairman so to have a professional with the corresponding equipment do it. Not that I do not trust your ability, but Mainland stuff may have a couple of quirks…

Both flat prongs are hot, the round one is neutral, or at least that is what it is supposed to be.

Taiwan 220 is 2 lives and one neutral. If its a Chinese/European/rest of the world 220 then you connect the lives to both of the round prong, and the neutral goes into the safety ground if present.

Both of those flat pins carry 110v. The round prong is not ground, it is the transformer center-tap.

If the oven was designed to be used in China, which has a single phase 220v system, then it should work ok in Taiwan. The oven’s live and neutral are connected to the two 110v phases and the oven’s earth is connected to the center-tap. If the oven has a bare, exposed metal case, it will probably tingle a bit when you touch it.

Dude. Pay someone the NT$500 to do it for you. If you have to ask this question you should not be trying to hook an oven into your a/c sockets.

[quote=“monkey”]Both of those flat pins carry 110v. The round prong is not ground, it is the transformer center-tap.

If the oven was designed to be used in China, which has a single phase 220v system, then it should work ok in Taiwan. The oven’s live and neutral are connected to the two 110v phases and the oven’s earth is connected to the center-tap. If the oven has a bare, exposed metal case, it will probably tingle a bit when you touch it.[/quote]

That’s new to me, ground/earth is meant to funnel electricity to the earth preventing from getting tingled or shocked when touching metal casings around electric appliances. :ponder:

And anyways, if there are no electronics involved connecting a resistor (which is an oven, and a light) it doesn’t matter which way you do it as long as the earth is connected to the right prong, everywhere in the world/universe it’s the middle one (normal household plug) … green/yellow striped mostly but other colors possible.

Well, the appliance’s ground is supposed to be attached to the center-tap (neutral) because that is supposed to be grounded. However, it often isn’t, or the ground connection is too poor to handle a heavy current. If there’s a short inside the appliance (live to the chassis or case) then the current will flow to the neutral and trip the overload protector in the wall fuse panel. Of course, it’s not as safe as a proport earth and current leakage circuit breaker, but it’s better than nothing.

The Americans used to have a similar 220V mains system to Taiwan, but have moved over to a 4 wire system now (2 lives, neutral and earth). It’s really a lot safer.

[quote=“monkey”]Well, the appliance’s ground is supposed to be attached to the center-tap u[/u] because that is supposed to be grounded. However, it often isn’t, or the ground connection is too poor to handle a heavy current. If there’s a short inside the appliance (live to the chassis or case) then the current will flow to the neutral and trip the overload protector in the wall fuse panel. Of course, it’s not as safe as a proport earth and current leakage circuit breaker, but it’s better than nothing.

The Americans used to have a similar 220V mains system to Taiwan, but have moved over to a 4 wire system now (2 lives, neutral and earth). It’s really a lot safer.[/quote]

The earth can never be connected to the ‘neutral’ … it always need to be earth …

If the earth fails and there is any leakage (through contact) than the current should be cut by a residual-current circuit breaker. Not because of overload, entirely different.

In Belgium I’ve never seen a neutral connected to the earth … but in Taiwan everything is possible …

BP and monkey are correct. It’s a two-phase system (not phase and neutral as you might be used to in Europe), it was originally copied from the US, and it’s not very safe.

The centre pin of the socket is the transformer CT but may not be held at earth potential - whether it is or not depends on the whim of the builder. I used to live in a building where it clearly was not, and at certain times of day you could get quite nasty shocks from anything with the casing “earthed”. One option would be to leave this pin unconnected and clamp the frame ground (safety earth) of the oven to a nearby water pipe, using a length of thick wire to extend as necessary. You may find there is a thick metal tab or screw attachment on the back of the oven specifically for this purpose.

Anyway, bottom line: the Shui Dian guys are a bit hit-and-miss, but at least you can blame someone else if it’s not right … so please take llary’s advice to avoid causing a fire or worse.

[quote=“finley”]BP and monkey are correct. It’s a two-phase system (not phase and neutral as you might be used to in Europe), it was originally copied from the US, and it’s not very safe.

The centre pin of the socket is the transformer CT but may not be held at earth potential - whether it is or not depends on the whim of the builder. I used to live in a building where it clearly was not, and at certain times of day you could get quite nasty shocks from anything with the casing “earthed”. One option would be to leave this pin unconnected and clamp the frame ground (safety earth) of the oven to a nearby water pipe, using a length of thick wire to extend as necessary. You may find there is a thick metal tab or screw attachment on the back of the oven specifically for this purpose.

Anyway, bottom line: the Shui Dian guys are a bit hit-and-miss, but at least you can blame someone else if it’s not right … so please take llary’s advice to avoid causing a fire or worse.[/quote]

Finley, you are right that a real earth would be the ideal solution. However, the pipes in most Taiwan high-rises are plastic (I’ve only ever seen metal pipes in very old buildings). So for 99% of people, the only usable earth is the rebar in the floors or external walls. But the rebar is difficult to get to, and may or may not provide a solid earth connection in the moment of need.

The 220v center tap can waver a bit from 0v, and this will depend on the amount of current its carrying at the time and the resistance of the return route to the transformer. It could even reach 110v in the case of flooding of the transformer or a Taipower service worker screwup. Sure you don’t want that on your appliance chassis/case, but the chances of it happening are miniscule.

I’d rather the peace of mind that the overload protection is going to trip in an emergency and just get used to that tingling feeling. The insane electricity distribution system is just one of those Taiwan Up things. :bow:

I wish I has taken some photos of the Frankenstein-style knife switches in the old place I once lived in. They really add character to a place and I miss them greatly.

I was told that you can ground to a metal switch case… but then most switch boxes I’ve seen are plastic unless they’re embedded into the wall.

[quote=“finley”]

Anyway, bottom line: the Shui Dian guys are a bit hit-and-miss, but at least you can blame someone else if it’s not right … so please take llary’s advice to avoid causing a fire or worse.[/quote]

You can’t blame someone else when you are already dead. On at least 2 instances when they have worked for me, they have done jobs that were potentially life-threatening.

  1. Installing small halogen spotlights in a plywood ceiling. Instead of using cheap, easily available twist-on wire connectors, they saved maybe NT$100 by just twisting wires and insulating them with sticky tape. The sticky tape was inches from the halogen lamps and was highly flammable (I tested it with a lighter). Sticky tape adhesive has a lifetime of just a couple of years before it deteriorates, leaving bare wires exposed. Not only that, but the entire surface of the ceiling was covered in a thick layer of fine sawdust (also highly flammable). I had to re-do the wiring myself.

  2. Installation of a jacuzzi-style bathtub. The underside of these bathtubs is a maze of plastic pipes and pumps leading to nozzles. Any of them could spring a leak at any time and nobody would know about it. The wiring for the pump? More twisted wires and sticky tape, laying on the ground directly under the tub where any leaking water would gather. No earth leakage protection. The contractor had to ask another electrician to re-do the wiring (who amusingly received a painful electric shock in the process).

Moral of the story? If you want a job done properly in Taiwan, do it yourself.

Ah, yeah … .fair point! I’ve seen it done once or twice here but I can’t remember precisely where … and thinking about it now, I’m wondering if they’d bonded the earth to a metal gas pipe :astonished:

I suspect they’re actually taught to do this at Taiwan Bodge-It Da Xue; I’ve never seen anybody anywhere use any other method, certainly not an insulated terminal block (in fact they seem to be like hen’s teeth in Taiwan - nobody even stocks them). I’ve even seen it done on cables that would be carrying significant current, and like you I had a halogen lamp wired up that way (I threw it away and replaced it with an LED type … and an insulated crimp slice). I’m sure the only thing that prevents Taiwan’s cities from going up in flames is the fact that you generally can’t maintain an arc with AC.

Still, what do you expect where the words for ‘water’ and ‘electricity’ appear together in a tradesman’s name? :unamused:

Sure, but only if you’re the kind of person who carries a multimeter in your toolbox. Otherwise, Mr twist-and-tape is probably (slightly) safer.

btw, love the knife switch. I’ve seen a few of those around too, complete with cobwebs. It’s a pity building management companies can’t hire an Igor to operate them for the full effect.

Finley, if you live out in the sticks somewhere, chocolate block connectors could be hard to get. If you need some, let me know and I can mail some to you. I have a access to a wide variety of sizes and the cost is trivial.

Thanks monkey … I can get them, but I have to go to the electronics shop to find them; here they’re considered a “specialist” item, unlike in (for example) the UK where you can buy them at any DIY shop. What baffles me is that things like that are, as you say, dirt cheap, especially if you’re paying trade prices. So why does nobody use them?

I think its laziness, but also if anyone has worked for any company in Taiwan doing blue or white collar work you will know that TW bosses will give you so much work that you HAVE to take shortcut in order to make the quota. I think its the same with truck driving, they’re given so many places to deliver to that they have to drive dangerously in order to make the deliveries.

I think its more to do with having to use the right sized wire nuts which takes time to sort out, but electrical tapes are quick and dirty.

It seems firms run by an average blue collar Taiwanese values quantity over quality.

Where is the OP? :astonished: