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 Post subject: wall outlet miswired, surge suppressor clue, & making an ada
 Post Posted: Sat Dec 06, 2014 2:27 pm 
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Joined: Sat Jun 30, 2007 10:36 am
Posts: 208
Solved.

Some wall outlets turned out to have been wired incorrectly, in that electricity arrives at the neutral and is meant to return to the power source through the hot, which is backwards (the grounding is okay). Electricity should arrive at the hot and return through the neutral. In a polarized outlet (newer two- and three-hole outlets are generally polarized, making it physically impossible to insert a plug the wrong way even if the grounding pin is absent), if we ignore the opening for the grounding pin, the neutral opening is supposed to be bigger than the hot opening. That corresponds to proper wiring, in which the neutral conductor has a cross-sectional area not smaller than that of the hot conductor, the difference usually zero in 120VAC and lower-voltage circuits but visible in high-voltage installations.

Electronics depend on DC (direct current) and on AC (alternating current) having been transformed into DC, and they includes computers, so I'd rather have electricity flowing correctly, even if things seem to work alright for the time being and even though it may not matter at all for some nonelectronic devices, like simple incandescent desk lamps. An analogy is from common battery-powered devices in which it is physically possible to insert AAA, AA, C, or D cells in either direction, but where instructions firmly state that each battery is to be inserted in one direction only. Presumably, with misdirection the device may not work properly or may be damaged.

The clue to the house wiring fault was that my new Tripp-Lite surge suppressor's LED indicating "PROTECTED" failed to light. Something had to be wrong with the incoming power or there was damage in retailer handling or shipping or Tripp-Lite was liable. I used a grounding tester to find the fault. The grounding was working but the tester lit up when I connected neutral to grounding (or neutral to hot) but not hot to grounding.

No store I've asked sells a crossover adapter; and, apparently, Leviton doesn't make one (at least the firm didn't answer an email asking). So I made one, using gauge 12 wire (one green wire and two nongreen wires), a do-it-yourself plug kit, and a do-it-yourself receptacle kit, the whole to accommodate 125 volts and 15 amps. A continuity tester would have helped but artful use of the grounding tester made up for it. The total cost was roughly $10 for parts and, in my case, several hours (12-gauge wire is stiff and I made idiotic mistakes I corrected before plugging it in). A wire stripper/cutter was about $6-8 and could have been bought for less and each tester was probably about $1-2. Screwdriver types and sizes needed depend on the kits. Needlenose pliers were very helpful for hooking the wire. I labeled my homemade adapter, hoping no one would misunderstand or misuse it (no one's likely to use it anyway).

A potentially easier and cheaper design would be a standard 3:2 adapter that is not polarized on the plug side for the hot and neutral holes. Assuming availability (more on that below), I would plug it in upside down. Attaching the grounding connector (usually a green metallic loop or a 1-2" green wire with a "C"-shaped connector) on the plug side probably requires one short bolt, one nut, and one (possibly additional) short green wire. Although the 3:2 adapter's plug side cannot be polarized for the hot and neutral for this use, the adapter's receptacle side should be fully polarized, which might make a very unusual adapter. An alternative is to get a fully polarized adapter and trim (grind, shave, or file) the neutral pin to remove its polarization, which may not be easy to do, and one large hardware store refused to do it, suggesting it would be illegal (I doubt that). If the adapter is not polarized for the neutral on either the receptacle or plug sides, one could label the receptacle side to tell users to use the adapter as if fully polarized, but likely few will read the label.

Three-to-two adapters must be grounded all the way. But apparently most users of 3:2 adapters don't realize that attaching the grounding connector is mandatory for safety if any consuming device (such as a computer) is grounded or uses a plug with a grounding pin.

Nonpolarized adapters and taps are available. Old ones should still exist and Radio Shack sells European-to-U.S. physical adapters that a sales representative said are nonpolarized on the plug side (and said that they don't change voltage or amperage); but for my use I'd have to remove the grounding pin and ground it another way. I can do that by plugging an ordinary fully polarized 3:2 adapter into the receptacle side of the Eur:US adapter and grounding the 3:2 adapter's plug side, as described above. I found a store selling a nonpolarized 6:2 tap for about $1.19; I used pliers to yank out the grounding pins, applied electrical tape to cover the now-useless holes on the receptacle side, and added 3:2 adapters so I could ground the assembly.

Electrical assembly and working with any adapter require proper precautions for safety.

Happily, my surge suppressor's "PROTECTED" green LED is now lighting up, like it should. And I notified an appropriate person where I found the miswired outlets, about them.


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