Pre NEMA receptacle?

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That is interesting. Did you take that pic or did someone send it to you? Reason I ask is the washer looks new. Did someone cut the ground blade off?
The picture is there just fine; not sure what iwire is talking about. Maybe his browser is not loading pics...
 
mgookin said:
That is interesting. Did you take that pic or did someone send it to you? Reason I ask is the washer looks new. Did someone cut the ground blade off?
The picture is there just fine; not sure what iwire is talking about. Maybe his browser is not loading pics...
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Sent to me, the washer is supposedly (supposedly) plugged in via a grounding adapter.
 
mgookin said:
The plug is not inserted all the way. Look at the gap.
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that's the cheater adapter you are seeing.

We run into those receptacles all the time here. I do not know why the ungrounded side is also t-slotted unless these things were designed to accept 15A 250V plugs (that have both pins turned sideways)
 
Sorry, but I had to laugh (geezer moment)... I installed many of these when I was a young lad. Ground lead from the adapter was supposed to land on the plate mounting screw, few ever made it. How about the receptacle adapter that screwed into a porcelain lampholder?
 
mbrooke said:
But they still make them :D


http://www.ehydroponics.com/cap-universal-x-plug-120-240-outlet-receptacle.html?opencatcontent=yes
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I know that. They are not UL listed, and if they show that they are, UL needs to be notified. I found some in a light controller and UL had me send in one of them and they started an investigation on the company that made the controller.

Those receptacles are not illegal to manufacture, and they are only illegal to install where the NEC is enforced.
 
mtfallsmikey said:
How about the receptacle adapter that screwed into a porcelain lampholder?
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I have a couple, they are still being sold. They are great for using a plug in breaker tracer sending unit to locate a lighting circuit breaker.

They are also UL approved.

shopping
 
K8MHZ said:
Probably earlier. I have them in my house which was built in the 40's. They are called 'double T slot' receptacles and are no longer allowed by the NEC. They could be used for either 120 or 240 volt circuits, and accepted both 15 and 20 amp plugs.
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Have you ever seen a made-for-US market appliance or lamp that used an ungrounded 15A 250V 2 prong plug? I've never even seen a 15A 250V 3 prong plug on an appliance, tho 20A plugs are quite common on hotel PTACs, and the last we put in at a residence was for a 4kw forced air space heater.
 
K8MHZ said:
Probably earlier. I have them in my house which was built in the 40's. They are called 'double T slot' receptacles and are no longer allowed by the NEC. They could be used for either 120 or 240 volt circuits, and accepted both 15 and 20 amp plugs.
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JFletcher said:
Have you ever seen a made-for-US market appliance or lamp that used an ungrounded 15A 250V 2 prong plug? I've never even seen a 15A 250V 3 prong plug on an appliance, tho 20A plugs are quite common on hotel PTACs, and the last we put in at a residence was for a 4kw forced air space heater.
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Guys, those old double tee receptacles were never intended for 240 volts or 20 amp equipment. The reason for the t slots existence was that in the early 1900s there were two competing 120v plug designs- the modern parallel and a 2 prong tandem Flat design and the t slot was simply a device that would accommodate both plug types.

The reason for the dual 125v/15 amp 250v/10 amp rating on old receptacles (many old recs that only accept parallels are marked the same way) is b/c lighting ckts were limited to 10 amps for ckts over 125 volts until the 1950s or so due to some rule in the NEC from what I've read.

There is no evidence that the t slot was ever recognized as a true Nema pattern and Nema standards changed in the 50s or 60s to where flat blade plug designs were reserved for 220 v or higher voltages to kind of give you at a minimum an approximate age of 120v equipment that has that old plug......

Beyond that, the old double tees were effectively banned by the 1971 NEC rules on interchangeability.

mbrooke said:
But they still make them :D
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Yes they do still manufacture that old t slot and it's called a Leviton 5000-i and it, much like the beast in your link, isn't listed. The 5000-i is for replacement use only, but no way should they be put in- rewire, gfci options or a brand new 1-15 only where one is removed.
 
mbrooke said:
But wait, that would mean such an outlet was indeed good for 250 volts, right?
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Sure they were- they had the rating. Even some old light switches, light fixtures,even Hubbell t slot socket adapters had a similar dual rating. But don't bother asking why the ampacity limitation for gen/lighting ckt over 125v- I have no idea, and obviously the question would be where would such voltages be used/available over here for those ckt types. Many dwellings built in the early 1900s that had these devices installed only had 120v svcs.

The theory about 240v equipment being used in those recs makes sense except that there is a dearth of equipment from that era that could have used 240 and had a tandem blade plug that could fit the t slot rec and as mentioned above the other "parallel only" rec type and other devices had the same dual rating. Its also doubtful that, even then, such a device would be permitted in which an accident (120 equipment hit w/240) could so easily occur if the outlet's true voltage was unknown.
 
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user 100 said:
Sure they were- they had the rating. Even some old light switches, light fixtures,even Hubbell t slot socket adapters had a similar dual rating. But don't bother asking why the ampacity limitation for gen/lighting ckt over 125v- I have no idea, and obviously the question would be where would such voltages be used/available over here for those ckt types. Many dwellings built in the early 1900s that had these devices installed only had 120v svcs.

The theory about 240v equipment being used in those recs makes sense except that there is a dearth of equipment from that era that could have used 240 and had a tandem blade plug that could fit the t slot rec and as mentioned above the other "parallel only" rec type and other devices had the same dual rating. Its also doubtful that, even then, such a device would be permitted in which an accident (120 equipment hit w/240) could so easily occur if the outlet's true voltage was unknown.
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True, but in my eyes you would not list something as 250 volts unless it had the option of being used as such in the real world. For example, my understanding is that keyless sockets are listed as 250 volts because they can be applied to such a system when sold in countries that use 230 volts.
 
mbrooke said:
True, but in my eyes you would not list something as 250 volts unless it had the option of being used as such in the real world. For example, my understanding is that keyless sockets are listed as 250 volts because they can be applied to such a system when sold in countries that use 230 volts.
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Like I said, in this case with the t slot it had to do w/ the NEC. I don't think the manufacturers of the old devices were trying make them compatible with other voltages used globally.

IIRC, there was an NEC 10 amp limit for lighting ckts originally- this was likely because of circumstances surrounding the lack of conveinence recs/modern branch ckts in dwellings at that time- think of an iron plugged into an adapter screwed into a lamp with is plugged into adapter screwed in ceiling socket and all of that small conductor (cords) carrying that load- a lot of fires then. Eventually it was raised to 15a in the 1920s (makes sense b/c of the growing use of wall recs in new installations deeming all those adapter doohickeys/cords draped everywhere increasingly unnecessary) , but the old rule was still in effect for lighting ckts over 125v and stayed that why until the '50s- no clue why as it made no sense. (sorry to sound repetitive:p)
 
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