dirty dawg
Member
What was the last year they used non grounded 120 volt outlets in american homes?
Thanx.
Thanx.
Question over old outlets
- Thread starter dirty dawg
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dirty dawg
Member
Re: Question over old outlets
Cool! Thanx. For some reason I was thinking it was 1972 but wasn't sure.
Now, here's another old outlet question...
In the older homes I've noticed two types of 120 volt outlets used. One type just has the vertical slots. Then there's another type, which I believe is referred to as a "combination 15 amp/20 amp outlet." It has the vertical slots as well but in addition to that it has horizontal slots that "tee" into the vertical slots. Both the hot and the neutral sides of this outlet have the extra slots cut into it.
I was curious when the first and last years of this "combination" outlet was used? Seems like most homes I've seen built in the mid 50's to late 60's had them?
Thanx again.
Cool! Thanx. For some reason I was thinking it was 1972 but wasn't sure.
Now, here's another old outlet question...
In the older homes I've noticed two types of 120 volt outlets used. One type just has the vertical slots. Then there's another type, which I believe is referred to as a "combination 15 amp/20 amp outlet." It has the vertical slots as well but in addition to that it has horizontal slots that "tee" into the vertical slots. Both the hot and the neutral sides of this outlet have the extra slots cut into it.
I was curious when the first and last years of this "combination" outlet was used? Seems like most homes I've seen built in the mid 50's to late 60's had them?
Thanx again.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Question over old outlets
Thanks, that answered my first question.
Now:
1. When was NM cable first allowed in the NEC?
2. The first NM w/ ground cable used a reduced size equipment grounding conductor, wasn't it 14 AWG for 12-2 NM? What year was NM cable introduced with the reduced size equipment grounding conductor (if I am correct on that)?
Thanks, that answered my first question.
Now:
1. When was NM cable first allowed in the NEC?
2. The first NM w/ ground cable used a reduced size equipment grounding conductor, wasn't it 14 AWG for 12-2 NM? What year was NM cable introduced with the reduced size equipment grounding conductor (if I am correct on that)?
tonyi
Senior Member
Re: Question over old outlets
The first nasty 2-wire NM showed up sometime around 1920 I believe.
That undersized gnd was also used on #10 - I just rewired a 30A dryer some dope used that stuff on (and they used a 10-2. Insulated neutral?!?). It looked like the gnd was about #14. on the #12's that gnd isn't even a #14, more like a #16, its real flimsy. If a breaker failed and you wound up having to trip the main on a fault, things could get pretty toasty pretty quick
The first nasty 2-wire NM showed up sometime around 1920 I believe.
That undersized gnd was also used on #10 - I just rewired a 30A dryer some dope used that stuff on (and they used a 10-2. Insulated neutral?!?). It looked like the gnd was about #14. on the #12's that gnd isn't even a #14, more like a #16, its real flimsy. If a breaker failed and you wound up having to trip the main on a fault, things could get pretty toasty pretty quick
dana1028
Senior Member
- Location
- San Francisco Bay area
Re: Question over old outlets
RE: undersized EGC in NM cable...I'm wondering if that was a UL thing. Up through 1984 the NEC said (regarding EGC in NM)..."In addition to the insulated conductors, the cable may have an approved size of insulated or bare conductor for equipment grounding purposes only."
In 1987 this changed to require this EGC to be sized according to Art. 250 ("when provided, the grounding conductor shall be sized in accordance with Art. 250)...Table 250-95 (Min. Size EGC) required full sized conductors for 15-, 20- and 30-amp circuits.
RE: undersized EGC in NM cable...I'm wondering if that was a UL thing. Up through 1984 the NEC said (regarding EGC in NM)..."In addition to the insulated conductors, the cable may have an approved size of insulated or bare conductor for equipment grounding purposes only."
In 1987 this changed to require this EGC to be sized according to Art. 250 ("when provided, the grounding conductor shall be sized in accordance with Art. 250)...Table 250-95 (Min. Size EGC) required full sized conductors for 15-, 20- and 30-amp circuits.
dana1028
Senior Member
- Location
- San Francisco Bay area
Re: Question over old outlets
dirty dawg - those receptacles you are referring to were 15A, 125v OR 10A, 250v receptacles. I have a very clear photo of one of those, just don't know how to attach it here.
The photo link was provided through the consideration of Wayne C. (awwt).
You can see that this innocent looking 15A (2-prong) receptacle could actually be wired up for 240v !!! what a surprise for someone!
[ November 17, 2003, 07:48 PM: Message edited by: dana1028 ]
dirty dawg - those receptacles you are referring to were 15A, 125v OR 10A, 250v receptacles. I have a very clear photo of one of those, just don't know how to attach it here.
The photo link was provided through the consideration of Wayne C. (awwt).
You can see that this innocent looking 15A (2-prong) receptacle could actually be wired up for 240v !!! what a surprise for someone!
[ November 17, 2003, 07:48 PM: Message edited by: dana1028 ]
G
Guest
Guest
Re: Question over old outlets
Wouldn't it be 20amp 125 volt?
Wouldn't it be 20amp 125 volt?
dirty dawg
Member
Re: Question over old outlets
Wayne, it looks like the outlet you've posted a pic of, except it has that horizontal slot that you see on the neutral side as well as the hot side, plus it does not have the ground hole.
Seems like most of the houses I've seen them in were built in the later 50's into the 60's. I was curious on the years they were actually used.
I have a pic somewhere if I can find it...
Thanx.
[ November 17, 2003, 05:54 PM: Message edited by: dirty dawg ]
Wayne, it looks like the outlet you've posted a pic of, except it has that horizontal slot that you see on the neutral side as well as the hot side, plus it does not have the ground hole.
Seems like most of the houses I've seen them in were built in the later 50's into the 60's. I was curious on the years they were actually used.
I have a pic somewhere if I can find it...
Thanx.
[ November 17, 2003, 05:54 PM: Message edited by: dirty dawg ]
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Question over old outlets
The photo that Dana posted are no longer allowed as the NEC says that they can't be interchangable.
406.7 Noninterchangeability.
Receptacles, cord connectors, and attachment plugs shall be constructed so that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended. However, a 20-ampere T-slot receptacle or cord connector shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Non?grounding-type receptacles and connectors shall not accept grounding-type attachment plugs.
The photo that Dana posted are no longer allowed as the NEC says that they can't be interchangable.
406.7 Noninterchangeability.
Receptacles, cord connectors, and attachment plugs shall be constructed so that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended. However, a 20-ampere T-slot receptacle or cord connector shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Non?grounding-type receptacles and connectors shall not accept grounding-type attachment plugs.
dana1028
Senior Member
- Location
- San Francisco Bay area
Re: Question over old outlets
It looks like 1975 is when the code changed; i.e. it added code sections prohibiting the interchangeable types of receptacles. 210-7(f) and 410-56(e) were added.
It looks like 1975 is when the code changed; i.e. it added code sections prohibiting the interchangeable types of receptacles. 210-7(f) and 410-56(e) were added.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Question over old outlets
I have seen those receptacles before, but it never dawned on me that you could easily run 240V through it. Thanks for bringing it up Dana.
I have seen those receptacles before, but it never dawned on me that you could easily run 240V through it. Thanks for bringing it up Dana.
bill addiss
Senior Member
Re: Question over old outlets
I've often wondered what they were thinking when they made those.
Bill
I've often wondered what they were thinking when they made those.
Bill
tonyi
Senior Member
Re: Question over old outlets
Maybe dancing visions of potential european sales during the post-war reconstruction era. A universal unit that would work either side of the pond. We weren't going to get'em off 220V, but with all the US bucks flowing in maybe we could get'em to use our plugs...
Yea right.
Maybe dancing visions of potential european sales during the post-war reconstruction era. A universal unit that would work either side of the pond. We weren't going to get'em off 220V, but with all the US bucks flowing in maybe we could get'em to use our plugs...
Yea right.
dirty dawg
Member
Re: Question over old outlets
But now if that outlet could be used for 240 volts, was it most likely in another country? Because most of the 240 volt outlets I've seen here in the US (I believe) are made up of two 120 volt lines, then the neutral (and sometimes a ground). Over in Europe and other middle eastern countries I believe it's only one 240 line and then a neutral. (That's correct isn't it it?)
And since it's sort of a "universal" outlet, I take it that's why they're not made anymore? Because they still sell the standard type vertical slot non grounded outlets at Lowes and other home supply stores but they don't sell these.
Tonyi, in your post, were you referring to that these outlets began being produced after WWII? (Just curious)
Thanx.
[ November 18, 2003, 01:47 AM: Message edited by: dirty dawg ]
Thanx....yes that is it....that is a definite pic of the outlet I'm referring to! But of course I had a guy tell me it was a "combination 15 amp/20 amp outlet." And in a way it seems to make sense since I've noticed on a 20 amp plug one blade is vertical and the other is horizontal.Originally posted by dana1028:
dirty dawg - those receptacles you are referring to were 15A, 125v OR 10A, 250v receptacles.
The photo link was provided through the consideration of Wayne C. (awwt).
You can see that this innocent looking 15A (2-prong) receptacle could actually be wired up for 240v !!! what a surprise for someone!
But now if that outlet could be used for 240 volts, was it most likely in another country? Because most of the 240 volt outlets I've seen here in the US (I believe) are made up of two 120 volt lines, then the neutral (and sometimes a ground). Over in Europe and other middle eastern countries I believe it's only one 240 line and then a neutral. (That's correct isn't it it?)
And since it's sort of a "universal" outlet, I take it that's why they're not made anymore? Because they still sell the standard type vertical slot non grounded outlets at Lowes and other home supply stores but they don't sell these.
Tonyi, in your post, were you referring to that these outlets began being produced after WWII? (Just curious)
Thanx.
[ November 18, 2003, 01:47 AM: Message edited by: dirty dawg ]
dirty dawg
Member
Re: Question over old outlets
I don't think I've ever saw a non polarized 2 prong duplex outlet....with the exception of the pic of the one that has it's face removed from the rest of it....aka the "porcelain outlet."
Seems like most of the homes I've seen those "t-slot" outlets in were built in the 50's and 60's so that's why I was thinking you meant maybe they were made after WWII....but not all homes have them. The house I grew up in was built in 1948. Out of all of the outlets it had only three that I remember were the t slot type and the rest were the standard 2 prong duplex outlets. My grandfather's house was built in the early 60's and it had those t slot ones in every room of the house except the kitchen and the garage.....they were grounded 20 amp type.
I don't think I've ever saw a non polarized 2 prong duplex outlet....with the exception of the pic of the one that has it's face removed from the rest of it....aka the "porcelain outlet."
Seems like most of the homes I've seen those "t-slot" outlets in were built in the 50's and 60's so that's why I was thinking you meant maybe they were made after WWII....but not all homes have them. The house I grew up in was built in 1948. Out of all of the outlets it had only three that I remember were the t slot type and the rest were the standard 2 prong duplex outlets. My grandfather's house was built in the early 60's and it had those t slot ones in every room of the house except the kitchen and the garage.....they were grounded 20 amp type.
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