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Bob,
What you have there is an OLD outlet that could deliver 120 or 240 v. Get a voltmeter and you’ll see.
There were an amazing variety of receptacle outlets in use up through the 1920s and even into the ’30s.
I find the odd one occasionally on reno jobs. The earliest receptacle outlet was the same a lighting outlet (the Edison screw base–the standard screw-in light bulb!) Appliances and even extention cords were made to screw into the Edison outlet. Weird! Pretty important to screw in the bakelite plug when you unscrewed the appliance or extention cord…
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I used to live in an early 1930's apartment building which had a central radio aerial mounted on the roof and special outlets in the living room with three prongs... two for power and a third for the antenna. They made radios for this with special plugs. It must have been state of the art at the time. Perhaps one or more of the prongs on your outlet did something else besides delivering power.
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No no no, Pete is right. This outlet was actualy made to conform to a short-lived nema standard code from the fledgeling nema folks, which called for a ground line, and an additional 'back-up' ground line. It was thought that sometimes one of the ground electrodes would take a backwards charge to the electrical particles running through the wire, and the second ground electrode would provide a new, uncharged channel for the trapped and rioting particles.
The basis for this was the, (also short-lived), theory that electrical particles come in 3 different types. Each would travel through the molecules of any metal in a certain way. In nature those particles are each drawn to a certain configuration of molecular structure. In any given molecular structure in nature you would find one or at most two of the three types of electrical particles.
Since nature doesn't refine metals in the same way that we do, the molecular structure of any of our conductors would be dissimilar to any other molecular structure found in nature. Add to that the fact that nature never creates all 3 electrical particles in one common source. It was feared that our methods of creating all 3 electrical particles from one source, and then forcing all 3 of those types through the unnatural molecular structure of the common conductors of the day held the possibility of a bottleneck of any or all of the particular types of electrical particles and consequent backward charge of the conductor. Thus the second ground conductor was introduced as a 'pinch of prevention'.
The outlet did, of course, still work with the older 'one ground' plugs.
The theory was originaly postulated by Jim 'crazy legs' Hostleman, who was Edison's right-hand man in charge of the development of the old Edison screw base outlet. The theory was later debunked by Charles Ingalls Rassmuson, a soviet cabinetmaker and gold-miner who proved the existence of all 3 types of electrical particles in the electrical pulses controlling the beat of a pig's heart.
*Hi Bob,You should send this to David Shapiro (try [email protected]) He specializes in old house wiring. I think he would get a kick out of it, and might even have more details for you. You might also check his book on old house wiring, or even his web site, which I think ishttp://www.erols.com/David.Shapiro/#contractor-consultant
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Bob,
I re-read your post and suddenly it hit me--
the location of the receptacle tells all!
As I said, the outlet is a dual 120/240 receptacle. The question is, why have such an outlet in the living room, relatively high on the wall, no less.
I believe that the outlet was installed there for an electric fireplace! These were very popular in upscale homes in the 1920s and '30s--they were sold as a modern convenience, no coal or wood, no ashes, no smoke on the house, no risk of a chimney fire.
Being a big resistance load, the larger ones ran off of 240 v. Smaller ones used 120 v. Hence the dual voltage. It's possible that there is a hearth and flue back there, sealed off when the electric fireplace was installed. Or, maybe the house was built with a 'chimney' on the exterior just for looks, and there was never a conventional fireplace.
These electric fireplaces looked king of cheesey, based on what I've seen of advertising photos from the period. But they probably provided more heat to the room than a conventional fireplace. And they were modern, high-technology appliances of the day, and would likely be found in an upscale home like a foreman's.
Frank--got a kick out of hearing that an uncle tried an Edison-base outlet on for size! If you want to start a museum of antique electrical devices, let me know...I too have some fine pre-NEMA ROs (including the combo power/aerial outlet mentioned). I can't seem to being myself to toss 'em out. Also if you're doing any K&T new work these days, I have some like- new...
Regards.
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ROFLMAO! So you are the ghost that inhabits/ed my house! Luka, you really need another outlet--say, hmmm, publishing? Dunno, but you crack me up. (No snide comments, folks.)
*All right, already. Not to disagree with Luka, I finally got a chance to look up the receptacle in question. I have seen these years back working in old houses in Brooklyn. Page 90 of David Shapiro's book "Old Electrical Wiring" shows a picture of exactly the outlet you have, in his section on "Outdated designs that have to go." Dave discusses why these devices no longer meet code, etc. and what to do with them.I expect you don't plan on using it, anyway, but they were combo 120/240 receptacles from the old days. No ground, of course.Sorry to burst your bubble, Luka. Enjoy. Rich.
*C'mon, RichMast, most of us don't have that book. Be kind and print out the details. I'm sure Mr. Shapiro won't mind if you share his words with us.
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it was late the supply house was closed it was the only outlet i had on my truck with a matching plug.i didnt think anyone would care. oh well"
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Actually, there wasn't much else about it in the book. The paragraph was titled "other odd outlets" and said (direct quote from Mr. Shapiro):
"There are many other oddly shaped receptacles that will not accommodate any modern cord connectors. Others will accept two-prong connectors but will not accommodate ground prongs. Like crowfoot receptacles, it may be possible to replace them with modern receptacles, once you check wiring polarities. Like crowfoots, though, they may well indicate the presence of old, deteriorated wiring."
There you go. He said it - the outlet is no longer usable, and may indicate deeper troubles. I was avoiding the whole "if you don't know what you're doing, call in a pro" post in what has been a good (and humorous) thread, while giving information from my experience and references.
The caption of the picture showing the outlet in question was actually the most relevant. It said "Mostly used for 120 volts, they could alternately be wired for 240 volts."
The book is great, especially if you do work on old houses. Pointed out a lot of land mines which I hadn't seen or even thought of.
Hope this helps. Rich.
*For those of you like CAP who have either pictures or the actual item of old electrical stuff, David Shapiro probably wouldn't mind getting a copy. One of the reviewers noted that he didn't have enough pictures in his book.If you need more contact information than in my previous posting, e-mail me directly at [email protected] and I'll put you in touch with him.
*Thank You.
*i I believe that the outlet was installed there for an electric fireplace! These were very popular in upscale homes in the 1920s and '30s--they were sold as a modern convenience.Yup. But not a 'fireplace' more of an ornamental heater. They were usually shallow in depth and in some cases were intended to sit in shallow 'fireplaces' without flues. I had a client who bought a house that still had one in it. Next time I'm there I'll ask to see the plug and get back to you. The heating elements sat behind ceramic grids that helped retain the heat. No insulation you know ...Jeff b Been there, done that, can't remember
*Great ideas. The niche it was in was about 1 1/2 - 2' tall and about 1' wide, rched at the top, and the bottom of the niche was about 4' off of the floor. So the cord for an electric fireplace would have been obvious, and there was no sign of any sort of fireplace structure there.I'm thinking the radio idea might fit, many houses around here still have radio antenna wire strung in the attics, although I don't recall any remaining in this particular house.Bob
*The big problem I can see with the Radio theory is that having the antenna lead bundled with the AC power would be the worst thing you could do for the AC hum problem. Shielding and filtering out AC hum were much harder to do way back then in the analog vacuum tube world.-- J.S.
*There were antenna and AC power outlets on the same strap. The antenna and ground plug was like a to prong crows foot style. AC hum was not a problem as that is at 60 Hz and AM radio is at 530 to 1600 (1500 back then) KHz. There might be iniduced static now from lamp dimmers and other solid state controllers. Most FM radios came for years with line cord antennas. The wire loops and ferrite loopsticks that could be installed inside of table radios for AM did away with the need for long wire antennas in attics, and therefore the need for antenna outlets went away in the 1930's.Frank
*I remember fm radios that got much better reception if you were able to loop the power cord up around a window or something. The antennae was in the power cord. Even when they first started with the ferrite rods and coils, they still relied somewhat on the power cord antennae.
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Ran across an old duplex outlet the other day, 4 horizonatl slots. Labeled from the top clockwise, call 'em 1, 2, 3, 4.
Using a tester light, 1 - 3 were hot, as were 1 - 4, 2 - 3, and 3 - 4.
Slots were "standard size"
anyone seen anything like this before? What were they used for?
Pic attached, but its a large file (about 350 KB)
Bob
*Just checked, Grainger's catalog. They must have every NEMA plug and outlet ever made...except yours.
*Sigh. Here's the pic in a reasonable file size.
*Reminds me of European outlets.Gabe
*Thanks. How'd you do that? I tried saving in different formats, different color renditions, and everything I tried upped the file size.Bob
*Bob, out of curiosity, it what part of the house is/was this outlet located? Is/was it connected to a dedicated breaker?Full of questions, but no answers... Steve
*From my NEC handbook...This looks closest to being a 3 phase, 250 V, 30 A receptacle. It is 3 pole 4 wire grounding, what you call #3 is the ground. 1, 2, 4 are Y, Z, X respectively, according to the illustration. It is designated 15-30R (it is on the 15th row of the illustration, under the 30 Amps heading.) Of course, I've never seen it before and still can't tell what it's use is. I also don't know what exactly X,Y,Z are. I, mean I know they denote the different poles, but how exactly that translates to the wiring...?I have the NEC 1999 handbook, published by NFPA, it includes the complete code text and a not-as-technical explanation of what they meant. This was in figure 210-6, page 69 in the hardbound book.Sean
*Bob, What you have there is an OLD outlet that could deliver 120 or 240 v. Get a voltmeter and you'll see.There were an amazing variety of receptacle outlets in use up through the 1920s and even into the '30s.I find the odd one occasionally on reno jobs. The earliest receptacle outlet was the same a lighting outlet (the Edison screw base--the standard screw-in light bulb!) Appliances and even extention cords were made to screw into the Edison outlet. Weird! Pretty important to screw in the bakelite plug when you unscrewed the appliance or extention cord...
*I use Adobe Photoshop, but the operations are so elementary they ought to be available with the software for your digital camera or scanner.1. Decrease the resolution to 72 lines per inch.2. Crop the photo to include only the necessary info3. Resize the image to less than 400 pixels on the longest dimension4. Save as a JPEGPS - making the image black and white will usually cut the file size way down too
*Thanks for the info.The outlet was in a 75 year old or so house, in an arched nook in the LR (about 2' high, about 4' above the floor,) on the interior wall where the fireplace would have been (had there been a fireplace), about where the central chimney mass was.The house was in a workers' housing type neighborhood (RR and associated light to medium industry) but this house was a cut above the average house in the neighborhood. (A foeman's?)As a "generalist" home inspector, I don't get time to thoroughly investigate every mystery I run across, unfortunately. In cases like this, I have to tell my customer to talk to an electrician (or other specilaist.) Sometimes, if time permits, at the end of an inspection I'll dig a bit deeper, but there's usually another inspection pending or family to get home to (or owners who aren't thrilled that I'm there in the first place) which prevents that. Bob
*CAP is right. I have also seen these outlets in houses of the 20's and 30's. I also have some of the tandem plugs that fit. This was long before NEMA.One of my uncles found out his big toe fit the edison base style outlet, but only once. Outlets were usually mounted in the baseboards of older homes, adding to the toe possibility.Frank
*It looks like an early type grounded outlet that could accept a ground prong from either side. this is for old ground prongs that were flat instead of cylindrical as they are today.Now bear in mind that none of the above info can be confirmed by anyone that I am aware of and it is possible that I made it up entirely but it sure seems like it could be true, doesn't it?Pete
*Pete,I can't say I have ever seen flat blade ground prongs on regular parallel blade 120 v plugs. I have seen people use three pronged crows foot outlets and plugs before the NEMA grounded outlets and plugs were available. I have also seen pictures of appliances and tools with the tandem blades and edison base screw plugs attached in books and magazines of the 20's and 30's. I have an edison base outlet I took out of a house. I also have some tandem bladed outlets that were removed from houses. My junk box is way overfilled.....Frank