I only know what my local AHJ goes by. And that is the 2005 version. They just switched (last year) from the 1994 version. I'm sure there'll be no switching again for quite some time.
Also, i think some of the confusion comes from the interpretation of the term "single outlet". SINGLE outlet does NOT mean a duplex outlet. And SINGLE (non gfci) outlets are allowed in basement and garages on a circuit for sump pumps and refrigerators. Whereas nothing else can be plugged into them without unplugging the device the outlet was intended for. Has this been eliminated for the 2008 version?
Yes, the "INTENT" is as you said, but many of the rules are totally stupid. For example, they even put a green ground screw on switches now. WHY? If the switch is in a metal box, it's grounded by the screws, but even in a plastic box, that small piece of metal on the front of the switch is covered by a plastic plate. Those old bakelite rotary swithces with the exposed HOT WIRE screws WERE dangerous, VERY dangerous. I would not even think of allowing such a thing. Not only can children touch them, but when I walk into a dark room fiddling around for the switch, I could easily touch them. In fact when I had that switch in my garage, I planned to replace it, but when I moved onto this property there were a million projects and all had priorities. Yet, I did apply some electrical tape over those screws shortly after moving here.
Old wiring was extremely dangerous. Much did not even make common sense, such as any exposed HOT electricity. Those old knife switches were insane on 120V AC. They were fine for a 6 or 12 V battery circuit, but allowing them, or even using them on 120V AC was just stupid. Yes, people were electricuted and some died, and fires started. Then in the 1950's and 60's, all wiring was in metal. Conduit, BX, metal boxes, etc. That was likely the safest wiring ever made. Now we have plastic coated cable in plastic boxes. Plastic burns. It's not as safe, but we rely on breakers rather than plug fuses which could often be oversized. Yet, nothing stops someone from hooking that #14 wire to a 30A breaker if they know how. It's just that back when fuses were used, ANYONE could change a fuse, now it involves the use of tools and some guys wont open any electrical box.
In some ways, wiring has improved, in others, it's gone backwards. I still believe that the old metal enclosed wiring was superior to what is used today. But much of that old metal enclosed wiring was connected to fuses, so we have advanced in the regard of breakers.
I do have GFCIs on all my outdoor outlets, but not those in my garage, basement, or bathroom. But those are all existing installations and have not been rewired except for a few outlets that were replaced due to wearing out or just wanting a grounded one to avoid hunting down those damn adaptors all the time.
Well, I should mention that ALL the current wiring in this garage IS up to code as far as the wiring itself, I just dont have GFCI outlets. Or, actually, I do have ONE. That one is above my workbench and is there for testing power tools or any other electrical devices that I am repairing. It also feeds the outdoor outlet on the garage, because I did not want a GFCI on the outside of the garage, knowing water can get into them no matter how well the covers are made. Once something is plugged into them, water can get in.
If it is fused at 15 amps it doesn't matter what kind of plug is on the end (as long as it is rated for at LEAST 15 amps - the circuit is protected. - code issues - if any- aside.
When you lookk at it logically - from an electrical point of view - it would make more sense to allow a 20 amp receptacle on a 15 amp circuit than the other way around. Look at it from this point of view. A 20 amp receptacle ic designed to handle 20 amp loads - on a 15 amp circuit it is protected to 15 amps. This is definitely safe as nothing can operate above its rated or protected current . A 15 amp receptacle is designed for a 15 amp load and when installed on a 20 amp circuit is protected at 20 amps and wired with wiring that is rated at 20 amps. The receptacle is now the week link, and being somewhat resistive in nature it is succeptible to overload damage if a load plugged into it draws more than it's rated current - as it is "protected" to a current higher than its rating.. This definitely has the possibility of being unsafe as the receptacle can operate above its rated current.
I believe he was saying nobody had ever died from HIS terribly dangerous and inadequate garage wiring. However, the fact that he allowed the garage to collapse before repairing the water leaks and rewiring the garage doesn't say an awfull lot for his analytic capacity or his maintenance regimen!!!!
You are only properly grounded in a metal box if the device is listed as self grounding (a spring or brass clip on the yoke) In a plastic box, there is no guarantee the plate will be plastic and you still have metal screws. Before the grounded switches, they only allowed plastic screws on switch plates but that rule was not followed much either.
NEC 210.21(B)(3) starts off by saying that section only applies to circuits with more than one outlet. We are talking about a SINGLE outlet. In which case, the following section applies:
" 210.21 Outlet Devices. (B) Receptacles. (1) Single Receptacle on an Individual Branch Circuit. A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit."
Since the 20 amp outlet has a rating greater than the 15 amp circuit, it may be used. Now, I would agree it doesn't make much, but that is what is says, and hence was my point.
That text is only part of the article, the table clarifies the rest. There is no ambiguity in the table.
You didn't have to wait long. Here it is. No need to get sarcastic and snippy.
" 210.21 Outlet Devices. (B) Receptacles. (1) Single Receptacle on an Individual Branch Circuit. A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit."
That is clear as day. A 20 amp single receptacle has an ampere rating greater than that of the circuit, hence it MAY be used. If they wanted to prohibit using a 20 amp or greater single receptacle on a 15 amp circuit, all they had to do was say the receptacle has to have a rating EQUAL to the circuit.
Actually it does say exactly what I said it does, as shown above. You're the one who's confused, which is OK, but why the attitude?
Yes, let's look at that section. In the same section where it starts to explain those tables it starts off with:
"210.21(B)(3) Receptacle Ratings. Where connected to a branch circuit supplying TWO or MORE receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3)"
The added emphasis is mine. Since we are talking about using a SINGLE
20 amp outlet on a 15 amp circuit, those tables do NOT apply.
Actually it's quite clear that you're the one who's wrong here. A simple admission to that and apollogy for getting snippy will suffice.
I think the reason for that initial statement in the code, is because a 40 amp receptacle can be wired with a 40 or 50 amp circuit, but the table makes it perfectly clear that a 20 amp receptacle can't be wired with a 15 amp circuit
Ground screws come on switches because there are a variety of ways to ground equipment, and some methods do require a ground screw. FYI in the 50's and 60's all wiring wasn't in metal. As early as the 20's wiring was available with or without a metal jacket, just as it is today. The conductor insulation has and continues to be improved as better materials become available.
According to the article it does matter. First of all, in legalese, saying "not less than" doesn't mean that it can be greater than. It just can't be less than. Second, the table in the same article shows that a receptacle on a 15 amp circuit cant' be rated over 15 amps. Personally, I'd like to know that if I have an appliance that has a 20 amp plug on it, and I find a 20 amp receptacle that I can plug it into, a 15 amp breaker isn't limiting the current.
That table is preceeded by the statement, which I provided and is shown above, that says it applies to circuits with TWO or more receptacles. If they wanted it to apply to ALL receptacles, including single outlet ones, they could have simply omitted the word TWO, but they did not. And the section right before it clearly covers the case of a SINGLE receptacle and allows a receptacle with a current rating equal to or greater than the circuit to be used.
It doesn't make a lot of sense to me, but that is what it says and it allows using a single 20 amp receptacle on a 15 amp circuit.
Again, here's what the section you are referring to says. From 2008 NEC,
210.21 (B) (3) Receptacle Ratings. Where connected to a branch circuit supplying TWO OR MORE receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21 (B) (3)....
The added emphasis is mine. We are talking about a SINGLE receptacle, so that section and it's table do not apply. Section 210.21 (B) (1), which preceeds it, specifically addresses the case of a single receptacle.
21210.21 (B) (1) Single receptacle on an individual branch circuit. A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.
Do you not agree that a single 20 amp outlet on a 15 amp circuit meets that requirement? Note that I'm not saying it makes sense to me, but it's clearly what it says.
I agree there is no abiguity in the table. The problem is the table applies to circuits with two or more receptacles and we are talking about a circuit with just one.
210.21 (B) (3) Receptacle Ratings. Where connected to a branch circuit supplying TWO OR MORE receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21 (B) (3)....
Here;s the section that covers the single receptacle:
21210.21 (B) (1) Single receptacle on an individual branch circuit. A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.
That table is preceeded by the statement, which I provided and is shown above, that says it applies to circuits with TWO or more receptacles. If they wanted it to apply to ALL receptacles, including single outlet ones, they could have simply omitted the word TWO, but they did not. And the section right before it clearly covers the case of a SINGLE receptacle and allows a receptacle with a current rating equal to or greater than the circuit to be used.
It doesn't make a lot of sense to me, but that is what it says and it allows using a single 20 amp receptacle on a 15 amp circuit.
I see what you're reading, but there is no text that says any receptacle, single or duplex, can have a rating higher than the circuit feeding it.
Again, here's what the section you are referring to says. From 2008 NEC,
210.21 (B) (3) Receptacle Ratings. Where connected to a branch circuit supplying TWO OR MORE receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21 (B) (3)....
The added emphasis is mine. We are talking about a SINGLE receptacle, so that section and it's table do not apply. Section 210.21 (B) (1), which preceeds it, specifically addresses the case of a single receptacle.
21210.21 (B) (1) Single receptacle on an individual branch circuit. A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.
Do you not agree that a single 20 amp outlet on a 15 amp circuit meets that requirement? Note that I'm not saying it makes sense to me, but it's clearly what it says.
No, I respect your logic, but I think that the Nec is written in an often incoherent legalese, which is why I use the handbook. It says that it can't be less than, but it doesn't say that it can be greater than. I think from a practical perspective, one should be able to expect a 20 amp receptacle to be fed by a 20 amp circuit
No, it is not "definitely safe". It's of questionable safety at best
No, it can't, because any device that draws enough current to overload a 15A circuit is not permitted to have a plug that will fit into a 15A receptacle. It will have a plug that fits only into 20A receptacles. That's why a 20A receptacle has a different configuration.
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