a mistake in a new update has created a conflict in the code #nationalelectricalcode #electrician #electrical #diy #romex #electricity #christmas #howto
I hate when i plug into a 20 amp dedicated circuit with the correct 20 amp receptacle and 20 amp plug to later discover a 15 amp breaker and the refrigeration equipment needs a constant 16 amps, my opinion would be never put a 20 amp receptacle on a 15 amp breaker "NEVER"
It makes no sense. Why put multiple 30a receptacles on a 15 amp breaker just so the client will have tripped breakers and then you can go back and fix it? Obviously, the person requesting the change has never been in business for himself because he would be drowning in call backs. He could hire one service technician to follow him around and fix his work. A real electrician would never put a 20a receptacle on a 15 amp rated circuit, period. The fact that the panel approved this is concerning.
Two different code panels is how that happens. They split the articles up into different panels and unless some of the same people are on both panels then something like this happens.
How about if we go the other way? Example: Running a 30 amp breaker, #10 wire to a 15 amp duplex receptacle. You break the tabs and pigtail both halves of the duplex receptacle with #12 wire to the #10 wire. Reason is to power two freezers that draw 23 amps when both are running. Why do it this way? Because the 30 amp circuit already exists.
Just to make thing clear you might want to put a duplex 20 amp outlet in. Your two ice boxes will be just as happy, the the next occupant get's some notice that there is power behind that outlet.
Openly admitting one's mistakes is something that really gains my respect and is solely missing from a large percentage of our society, sad to say. And I have to respectively agree that a 20A receptacle on a 15A circuit can pose a hazard only under some very coincidental conditions equivalent to a total solar eclipse in the US. For starters nema 5-20 plugs on heavy-duty duty equipment is very uncommon compared to a 6-15/6-20. Second, the breaker would also have to fail, and in the past there were actually breakers such as but not limited to, Federal Pacific Electric, and Zinsco, feel free to do some research on your own regarding these two manufacturers, but suffice it to say, there were many documented instances where these breakers were defective from the date of manufacture and failed to trip even on a dead short. Also even when the breaker is working as intended, sometimes people get frustrated when breakers constantly trip even though it's to keep you and the building safe, and decide to "fix the problem " by replacing the 15A breaker with a 20A or higher so it will hold. A building more than 60 years old might still be served by a fuse panel, in which case the fuse current ratings can be easily increased or eliminated altogether by inserting a penny, aluminum foil or other metal objects into the fuse holder.
A breaker trip point is a curve and not a fixed point, it is shocking, pun intended, how much of variation there can be depending on the curve type. I am like you; I do not think it is a good idea to rely on the breaker to protect the circuit when you could be intentionally overloading it by plugging in a device that is rated for more current than the circuit is designed for. We rarely trip a breaker in our house, because we don't intentionally overload the circuits.
In the real world, we _do_ rely on the breaker to protect the circuit. If the load contained a heating element that had a failure in which the load somehow increased, the wire does not help and the socket does not help. The breaker is solely responsible for protecting the circuit from overcurrent.
Breakers don't always work. As they age and they trip over the years eventually the breakers either take too long to trip or they never trip. Best to have a system that requires multiple failure points to cause catastrophe.
There is no ambiguity; the Code is correct. Both Code sections (406.4 and 210.21) are specifically referencing "two or more receptacles" (that's exactly what it says). Therefore, if there is only one - SINGLE - receptacle, then it may be fed with a branch circuit whose ampacity is less than that of the recep's rating.
I would put multiple 15a receptacles on a 20a breaker but I wouldn’t put a single 20a receptacle let alone multiples of them on a 15a breaker on my MEP drawings. I prefer 20a breakers for multiple 15a duplex receptacles, 15a breaker for single 15a duplex receptacles, and 20a breaker for single or multiple 20a duplex receptacle(s).
Lol....I wasnt planning on it...but I would think it's a good thing if an inspector that admits when they are wrong after being shown a proper code reference
No one who would even want to do such a thing should be anywhere near an electrical panel. Putting 20's on a 15 is one thing. But installing a receptacle specifically designed for 20 is inviting the destruction of that equipment.
This a cool find. I was just looking in this section of the nec for my video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-RgIqgOT3QgI.htmlsi=znZWUd6b6zt4d2ML This change would cause more fires in older homes with challenger breakers and others that never trip. I've bared witness to these welding breakers and customers still won't pay to replace panel or even just all the breakers. Crazy world.🙃
Its not a hazard. You could plug in 2 15A nominal devices and get 30A. That situation is no different than a single 20A device on a single plug. The circuit breaker is the overcurrent protection device, NOT the receptacle. Doesn't really matter if you think its a hazard or not..
It makes a lot of sense. Most 20 and 30 amp equipment is an intermittent load. Putting an electric dryer on a 20A circuit does not mean it will ever be on in concert with another high draw device. The breaker is the protection on the circuit; not the receptacle. That said, you are right that the text and table mismatch is bad news. I have dealt with NFPA documents 70 (electric), 58 (propane), and 780 (lightning) and never saw an error like this before. That there is no real world hazard in it does not excuse the oversight.
Perhaps I'm creatively deficient, but I'm struggling to think of any possible scenario where it would be in any way advantageous to put a higher-rated receptacle on a lower-rated wire/breaker. Why would somebody even ask for this as a code change in the first place?
Somebody who went to business school saw that the lower rated wire is much cheaper and figured the problems won't be noticed until well after the home sales close.
Personally, I dont see the issue if the breaker will catch it before anything fails. But I know better and you should build things to be stupid proof. Whos to say that an idiot puts in a 20a or 30a breaker in the future and not realize that the wore wont carry that amount of power. Im refitting my whole home's electrical and Im putting in 20a breakers with 12awg wire and 20a receptacles inside of 3/4in conduit.
I get that it's useless. Where is your argument that it's a hazard? By the way I enjoy your videos. I try to follow code updates as a layman and you help us do that.
I've noticed this in my master's class too! Pointed it out and my instructor tried to dismiss it as i was reading it wrong. Bringing this up again tomorrow lol
There is a mistake in 210.21(b). Where the code is wrong is that it allows smaller receptacles on larger circuits, allowing the receptacle to be a bottleneck, create resistance and fire. Namely the code says, "15 amp receptacles are allowed to be installed on 20 amp circuits". That needs to be changed. All components of a circuit should be at or above the rating of the breaker. The breaker should be tripping before the receptacle gets hot. Not the other way around.
@@Stevenj120volts The pass through rating doesn't affect the rating of the 15 amp receptacle. The receptacle is rated for 15 amps. The customer can plug in a 20 amp load into the 15 amp receptacle itself. There's many such cases of those causing fires on the net. I hope that makes sense to you. I can dig up the math if you would like a good estimate on the amount of heat 5 amps of overcurrent puts on a outlet. It's not a lot, it's a slow melt.
