electric outlet for window AC question

| From: snipped-for-privacy@bellatlantic.net (ehsjr) | Roy Q.T. wrote: | One Last Thing, For Ed & Phil : What you are saying is, You can't | install a 20A Receptacle on a 15A circuit, but, you can install a 15A | receptacle ona 20A circuit is that what you are saying the NEC allows | here ? Roy | | Yes. | Ed | | Then : You are right per se, and quite wrong de facto };-) Okay', and I | understand this very well , but I just hate it when posters assume that | the cat has 5 legs and start slinging crap around, like we have time to | toss the ball around in here. Roy

What this thread turned in to should have been in sci.engr.electrical.compliance.

Reply to
phil-news-nospam
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| Okay., I never said a 20R or any other type but a regular duplex or | single receptacle in my response to this post nor did i include TSlot or | 220vac outlets., so go ahead for that change: Use of 15Amp & 20Amp | receptacles on a 15Amp 125AC circuit is allowed., use of a 15A | receptacle on a 20Amp circuit is not permted.....It's really not much | difference but, that is what i was taught. Phil you Flatter me };-) Have | a nice weekend.

Just be careful to make the distinction between single outlet and multiple outlet circuits. The rules are reversed between them.

And remember that modern NEMA 5-15R and 6-15R receptacles, despite having no T-slot opening, are truly 20 amp capable. I have looked for, but found no rule, that prohibits the use of 5-15R receptacles on the minimum two counter-top 20 amp circuits in kitchens. The 20 amp rule refers to the circuit, not the receptacles. Of course you and I both would put 5-20R's in there anyway. That's probably what you mean by "defacto".

Reply to
phil-news-nospam

A 15 amp receptacle is manufactured to the same specs as a 20 amp receptacle, in terms of the current carrying capability. The only difference is that the 20 amp receptacle has a T slot so it can accept flat blades at 90 degress to one another. The 15 amp can't accept those 90 degree offset blades.

The idea that a 20 amp receptacle can handle more current than a 15 amp receptacle, without burning/melting or otherwise becoming defective, is incorrect.

Ed

Okay', and I

Reply to
ehsjr

I don't think so Ed; There are a variety of them and i read recently that the specs for a 15 & 20 amp receptacles are different, they might seem the same but the metals employed are tempered differently and their capacity is limited to there rating.

Believe me I am not making this up: A 15 Amp circuit will trip if it goes over the rated current with both 15 & 20A with no ill effects on them, but, the study specifically mentioned that 15A units on a 20A circuit can suffer as any underrated equipment used on the supply or convenience outlet circuitry., I do not think much of it either and have bought random duplex receptacles without minding there current ratings and am just a little self conscious about it now since this came up on this thread.,Given my past observations I am just reiterating the concept of careful circuit component matching to myself };-) =AEoy

Reply to
Roy Q.T.

| I don't think so Ed; There are a variety of them and i read recently | that the specs for a 15 & 20 amp receptacles are different, they might | seem the same but the metals employed are tempered differently and their | capacity is limited to there rating. | | Believe me I am not making this up: A 15 Amp circuit will trip if it | goes over the rated current with both 15 & 20A with no ill effects on | them, but, the study specifically mentioned that 15A units on a 20A | circuit can suffer as any underrated equipment used on the supply or | convenience outlet circuitry., I do not think much of it either and have | bought random duplex receptacles without minding there current ratings | and am just a little self conscious about it now since this came up on | this thread.,Given my past observations I am just reiterating the | concept of careful circuit component matching to myself };-)

Please list specific brands and model numbers of NEMA 5-15R (or 6-15R) receptacles which are not capable of handling 20 amps passing through the receptacle between terminals, and/or are not capable of handling a total of 20 amps between the 2 outlets on a duplex yoke. If you list other than major US brands, please also include their UL listing info.

All that I have seen, which do not include cheap imports with fraudulent UL labeling, will handle 20 amps in a 15 amp configuration.

Reply to
phil-news-nospam

Phil: I am through with this post. You may want to ask your physician to increase your dose of psychotropic drugs. Roy

Reply to
Roy Q.T.
050618 1619 - snipped-for-privacy@ipal.net posted:

How many of these 90 degree plug appliances do you have in your house?

Reply to
indago

On Sun, 19 Jun 2005 21:02:57 GMT indago wrote: | 050618 1619 - snipped-for-privacy@ipal.net posted: | |> On Sat, 18 Jun 2005 04:58:49 GMT indago wrote: |> | 050617 1548 - Michael Moroney posted: |> | |> |> snipped-for-privacy@webtv.net (Roy Q.T.) writes: |> |> |> |>> One Last Thing, For Ed & Phil : What you are saying is, You can't |> |>> install a 20A Receptacle on a 15A circuit, but, you can install a 15A |> |>> receptacle ona 20A circuit is that what you are saying the NEC allows |> |>> here ? Roy |> |> |> |> I am neither Ed nor Phil, but you have to be clear what is meant by "15A" |> |> and "20A". You have the slot configuration on the face (15A, NEMA 5-15R |> |> which is the ordinary outlet and 20A, NEMA 5-20R, has a T shaped slot |> |> which can accept either an ordinary 5-15P plug or a 20A 5-20P plug which |> |> has a horizontal pin) and how heavy-duty the metal in the device, whether |> |> it is rated to carry 15A or 20A through it. This leads to 3 possibilities: |> |> |> |> 15A rated device, 5-15R face; |> |> 20A rated device, 5-15R face; |> |> 20A rated device, 5-20R face. |> |> |> |> (The fourth possibility shouldn't ever exist) |> |> |> |> The first one may or may not exist legally. (like I mentioned, I have |> |> a suspect). |> |> |> |> The first two can be connected to a 15A circuit fine. The second and |> |> third are fine for a 20A circuit. Hooking the first to a 20A circuit |> |> could cook it just like connecting #14 wire to a 20A breaker. There |> |> is no reason for a device with a 5-20R face to be on a 15A circuit. |> |> Something with a 5-20P plug (rare) has a good reason for doing so and |> |> would overload a 15A circuit. |> | |> | Are you saying that the 15 amp circuit breaker would not trip out in this |> | case? |> |> It should trip it. This can be why 20 amp outlets are not permitted on |> multiple-outlet circuits with 15 amp breakers. They do not seem to be |> prohibited on single-outlet circuits. Maybe the distinction here is that |> on a single-outlet circuit, when it trips, it won't knock out other stuff. | | How many of these 90 degree plug appliances do you have in your house?

None. And I would avoid them on 120 volts, preferring to go to 240 volts for stuff needing more power. But I have been looking at going with a big expandable UPS that would need 20 amps at 240 volts for all my computers.

Reply to
phil-news-nospam

| Phil: I am through with this post. | You may want to ask your physician to increase your dose of | psychotropic drugs. Roy

I take it never did "get" what is clear and obvious in the NEC.

Reply to
phil-news-nospam
050619 1718 - snipped-for-privacy@ipal.net posted:

You don't suppose that you could plug this 240 volt plug into one of the T-slot 110 volt outlets do you?

Reply to
indago

| You don't suppose that you could plug this 240 volt plug into one of the | T-slot 110 volt outlets do you?

No. A NEMA 6-20P plug will not mate with a NEMA 5-20R receptacle. With the configuration oriented ground pin up, facing the receptacle, the left blade is the hot/line/phase blade on the 5-20R and is oriented vertical. The corresponding blade on a 6-20P is horizontal.

Reply to
phil-news-nospam

No, it can't happen. If you look at a 5-20R outlet with the ground pin down, the left slot is T shaped and the right slot is vertical. It can accept a vertical left slot 5-15P or a horizontal left slot 5-20P plug. The 6-20R also has the left slot T shaped, but the right slot is horizontal, and it cannot accept either the 5-XXP plugs. Nor can the

6-XXP plugs, with their horizontal right pin, fit in either of the 5-XXR outlets. And they don't make anything with a T shaped _right_ slot(1), which is the only way to make an outlet that could accept either a 5-XXP or 6-XXP plug. Go to Home Depot and play with 5-20R and 6-20R outlets and the various plugs and see.

(1) Any longer. My 1940 era house has outlets where _both_ sides are T shaped, but have no ground pins. (Anyone know why they were made that way?) They could accept any of the 5-XXP or 6-XXP plugs, but you have to cut off the ground pin, first. (And yes, if you cut off the ground pin you _can_ fit a 5-20P into a 6-20R upside-down, and vice versa)

Reply to
Michael Moroney

| (1) Any longer. My 1940 era house has outlets where _both_ sides are T | shaped, but have no ground pins. (Anyone know why they were made that way?) | They could accept any of the 5-XXP or 6-XXP plugs, but you have to cut | off the ground pin, first. (And yes, if you cut off the ground pin | you _can_ fit a 5-20P into a 6-20R upside-down, and vice versa)

I've heard the "double T-slot" was made to support either 110 volts or

220 volts (the voltages back then) in the same receptacle. That would seem to defeat the intention of having a different kind of plug, as you would lose the ability to prevent insertion into the wrong outlet. I wonder how many times people plugged 110 volt things into 220 volt outlets because of that. I've also seen them with additional opening space to accept ungrounded continental European plugs.
Reply to
phil-news-nospam

Thanks, Roy!

I would love to read the article if you can find it. My information came from UL and is dated 1991 - so if there is something new that superceeds it, I am eager to learn.

Ed

Reply to
ehsjr
050620 1126 - snipped-for-privacy@ipal.net posted:

Then, you don't have any of these T-slot plug appliances in your house? Does anybody here have a T-slot plug appliance in their house?

Reply to
indago
.

I doubt it.

Seems that "no one" makes a 120 volt gadget that draws more than 15 amps! (Even if it claims to have severl horse power motor!)

With the exception of electric stoves and clothes dryers, 240 outlets are as rare as hen's teeth with only a few being put in to support larger sized window air conditioners. Often these just "patch" onto the electric dryer circuit.

Must of this thread has been quite silly and pointless.

>
Reply to
John Gilmer

|> Then, you don't have any of these T-slot plug appliances in your house? |> Does anybody here have a T-slot plug appliance in their house? | | I doubt it. | | Seems that "no one" makes a 120 volt gadget that draws more than 15 amps! | (Even if it claims to have severl horse power motor!)

I have seen some air conditioners that do have them. I would guess the idea is to make use of existing outlets that are 120 volt 20 amp, rather that the disadvantage to many people of wiring a new circuit.

While searching for UPSes in the 1-3 kVA range, I've seen some with such a plug specified.

I'd rather go with 240 volts in these cases and have the circuit brought in. If I was putting an A/C in where one previously had a dedicated circuit, I'd go with 240 volts and convert the circuit if needed.

| With the exception of electric stoves and clothes dryers, 240 outlets are as | rare as hen's teeth with only a few being put in to support larger sized | window air conditioners. Often these just "patch" onto the electric dryer | circuit.

I've never actually seen such a patch job, and certainly would never recommend it. But in DIY type forums, I've seen a number of people ask how to do it (IMHO, that would not be a project for someone with so little experience in wiring they would have to ask how to).

| Must of this thread has been quite silly and pointless.

Most threads seem quite silly and pointless to me when discussing something that I don't happen to need. This particular thread certainly has gone off on a tangent (both in subject and in plug blades). But it has shaken up some dust that probably shouldn't be where it has settled long ago. I am considering making an information web page on the subject "15 vs 20 amps".

Reply to
phil-news-nospam

From: snipped-for-privacy@earthlink.net (indago)

050620 1126 - snipped-for-privacy@ipal.net posted: On Mon, 20 Jun 2005 02:15:39 GMT indago wrote: | You don't suppose that you could plug this 240 volt plug into one of the | T-slot 110 volt outlets do you? No. A NEMA 6-20P plug will not mate with a NEMA 5-20R receptacle. With the configuration oriented ground pin up, facing the receptacle, the left blade is the hot/line/phase blade on the 5-20R and is oriented vertical. The corresponding blade on a 6-20P is horizontal. Then, you don't have any of these T-slot plug appliances in your house? Does anybody here have a T-slot plug appliance in their house?

I've got one, it's next to a duplex outlet with a 3 outlet plate in the same box nest to a window in my room., I think they are here in the event we got a 220V AC unit all we'd need to do is change the Circuirt Breaker & the neutral over to it..... I don't think it's a good idea, since a 120V plug fit's into it., if one is not careful you'd end up ruining your equipment. =AEoy

Reply to
Roy Q.T.

Well, I saw on in a house that was "modern" in 1958 but had a fuse box. It did have the "heavy" circuits for the stove and dryer, however.

Folks put in these BIG window units because they don't have the money to put in Central Air and install an entirely new service. I never "opened up" such an installation, but dryer circuits are often/usually just 30 amps so #10 romex would be protected. It may not be "code" but it's not asking for trouble either.

True. But even if you are taking short cuts it doesn't mean you don't want to be a safe as you can manage without spending an arm and a leg.

It seems to me that the folks who create the NEC sometimes DO worry about economy and DO reason that it's better to have GOOD safety at reasonable cost over GREAT safety at a cost that encourages folks to just jury rig. But when they mandated the "arc detection breaker" I wondered.

Well, since we are on the subject:

I notice that the "dryer and stove" outlets with only three wires (chassis/neutral are bonded in the appliance) don't make any effort to connect neutral before hot. Of course, for the last 30 years dryers are completely "off" until you push the start button and the only 120 volt loads in the stove are the lamp and the timer so ...)

Fine. Put in a "questions and comments" BB if you can.

>
Reply to
John Gilmer

The UL standard is unchanged. Both 15 and 20 ampere receptacles must be capable of carrying 20 amperes continuous without damage.

-- Tom Horne

Reply to
HorneTD

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