I was asked to review the attached installation that had been installed by a licensed electrician. I came to the conclusion that he had connected up the attached outlet wrong, since the hot socket on the wall outlet would be the small prong. So I redid it as per the attached sketch.
I believe the manufacturer of the wall outlet was the one responsible for the error. He should have installed the socket with the ground on the bottom, but since there were four of these in a row, it was not just a manufacturing error, but probably a design error from the factory.
A little background; The switched outlets were purchased by "xxxxxxx", a charitable agency that has designed miniature water purification plants for use in developing countries. They bought the pumps, filters, ozonator, and switchbox.
Our church group, xxxxxx, preassembled the package in xxxxx, broke it down and carried it on the airline to Guatemala.
The installation team then cut and glued the piping system together.
Doing the electrical work meant connecting to the existing power system that had been brought into the room. The two wall outlets were ungrounded outlets, but they did have polarity, judging from the size of the holes. The two outlets were opposite polarity. The breaker serving the two outlets was a 20 amp breaker, but it also served a ½ hp well pump, and both the breaker and the well pump were 50 yards away. No way to bring a separate ground.
The two wires to the outlets were embedded directly in the concrete and were single 12 ga conductors that looked like N insulation. Both were blue.
So we drove a ground rod, and set up a grounding system with 8 ga bare wire to the box and connected neutral and ground together. I found the blue neutral and grounded it to get rid of the 0.2 volt difference between our ground and the neutral. I couldn't find a separate ground on the main breaker box 50 yards away.
Then I looked at these switched outlets and decided we had a real problem since the pump motors didn't look like double insulated motors.
That's when I decided we needed to rewire the switched outlets.
At any rate, the switched outlets looked like a manufacturing assembly error. Turning the outlet upside down saved the manufacturer about an inch of ground wire inside each device. I guess if you are a third world manufacturer??
The two screws on the left hand side of the device are black. The ground screw is green, the upper right screw gold, and the lower right screw silver, so I can see how the first electrician would hook it up the way he did.
Does the device, as supplied, meet the code? I believe it does not, if for no other reason, it does not have a manufacturer's name on it. I didn't think to look for a UL stamp.
If you want to get into this, I can probably get a sample of the outlet from xxxx. I am going to file a complaint with them, since they supplied the switched outlets along with instructions as to how to install them.
It was an interesting project. We also took a training team along to teach the locals how to use pure water and the advantages of it. We hope it will improve the health of the entire community.
Dave XXX yyy & zzz Engineering Co.
[This message has been edited by Webmaster (edited 03-26-2005).]
It looks to me like somebody accidently broke off the tab on the one on the right and instead of jumpering the two screws together on the left side of the outlet they thought it would be okie dokie to jumper it on the right.
The outlet on the left is the good one.
The question is whether or not the manufacturers employee who built this actually has an understanding of the way it is supposed to work. Do they even know what polarity is? A lot of places (and not just in the third world) do not require there assemby line workers to be knowledgable about how the product actually works.
I think it was an oopsie and they didn't understand what the consequences were of swapping the sides the leads were on.
It looks to me as though the original wiring (left-hand diagram) was correct, as is the design of the outlet.
With the ground pin upward, the larger slot on the right is the neutral, which is the silver screw. The black screws linked together on the left can be used as a permanent feed to the recept and switch, with the top-right brass screw used as the switched output to some other device.
Alternatively, to have the switch control the recept, you can do what the original electrician did here and apply power to the brass screw, the black/tab left side then just linking switched power to the hot (smaller slot) of the recept.
Or you can break tha tab and wire the recept and switch into completely different circuits. I'm not quite clear as to exactly what has been done to the grounding arrangements.....
Joe, The original wiring / Left diagram was done correctly. You are not switching the neutral in a two wire circuit if the Hot is switched before it gets to the plug. i.e. "the hot socket would be the small prong..." That's how it is supposed to be. If there is no ground at the source a connection at the load to Earth / ground rod may create more problems than it will ever cure. Ground pin on top or bottom is unimportant. However the relationship of small slot to ground pin is a NEMA standard and included in NEC Handbook. The confusion is that the receptacle is upside down to some installers. SOLUTION. Install the devices with the switch on the bottom and everything will be just fine. :-) Note: The supply house is currently out of the ones with the switch on the bottom :-) Alan