Overcurrent Protection for 16 AWG Extension Cords

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Basically the NEC does not care if you plug a #16 AWG extension cord into a 15 or 20 amp receptacle circuit. The NEC only cares about the listing of the cord as outlined in 240.5(B)(3).
 
At the risk of being another tome, to the OP, I would suggest finding what code cycle 240 B 5 3 was added, and then getting the supporting proposals and comments from the NFPA
 
infinity said:
It does not say that you can or you cannot. I cannot find it and you haven't been able to find it either because it doesn't exist in the NEC. As you stated in the OP 240.5(B)(3) is as close as you can get. If the extension cord is listed and has a 15 amp plug on the end then it can be used on either a 15 or 20 amp circuit. It would help if the NEC explicitly stated the requirements (20 amp circuits) like it does for field assembled cords sets in 250.5(B)(4) in 250.4(B)(3) but it does not.

I don't have access to UL817 so I can't comment as to whether or not that will answer your question. Is this question related to a specific application?
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Actually the NEC very clearly states one can NOT use a 16 AWG extension cord (which is clearly listed / labeled at 13 amps) where it is protected at 15 or 20 amps.

2020 NEC 240.5(B)(3) says: "Flexible cord used in listed extension cord sets shall be considered to be protected when applied within the extension cord listing requirements." The extension cord is listed at 13 amps, not at the plug rating of 15 amps. The label on the extension cord says 13 amps, UL 817 says 13 amps.The rating of the plug is inconsequential in this.

So far no one has been able to show me how that logic is incorrect.
 
Jim Reizner said:
Actually the NEC very clearly states one can NOT use a 16 AWG extension cord (which is clearly listed / labeled at 13 amps) where it is protected at 15 or 20 amps.

2020 NEC 240.5(B)(3) says: "Flexible cord used in listed extension cord sets shall be considered to be protected when applied within the extension cord listing requirements." The extension cord is listed at 13 amps, not at the plug rating of 15 amps. The label on the extension cord says 13 amps, UL 817 says 13 amps.The rating of the plug is inconsequential in this.

So far no one has been able to show me how that logic is incorrect.
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I disagree with your interpretation, the NEC doesn't say that, it leaves that to the listing which allows a 15 amp molded attachment plug suitable for a 15 or 20 amp circuit. 240.5(B)(4) says that if you make the cord in the field then the #16 gauge conductors are just fine on a 20 amp circuit so why should a manufactured cord be any different? You seem to be searching the NEC for some justification for your conclusion that doesn't exist.
 
tom baker said:
At the risk of being another tome, to the OP, I would suggest finding what code cycle 240 B 5 3 was added, and then getting the supporting proposals and comments from the NFPA
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Yes, a lot of digging - but I think I may need to go that route to get to the bottom of this. Your suggestion WAS helpful to me!

Glad to see that at least you understand the issue, as so many others don't seem to be able to grasp it.

I do seem to remember many, many NEC editions ago there was wording that allowed 16 AWG (and 18 AWG) in flexible cords to be protected at 20 amps. Perhaps something in one place in the NEC was changed, without making appropriate changes elsewhere. The NEC is not infallible.

Thanks again, Tom! I will post what if anything I find.
 
infinity said:
I disagree with your interpretation, the NEC doesn't say that, it leaves that to the listing which allows a 15 amp molded attachment plug suitable for a 15 or 20 amp circuit. 240.5(B)(4) says that if you make the cord in the field then the #16 gauge conductors are just fine on a 20 amp circuit so why should a manufactured cord be any different? You seem to be searching the NEC for some justification for your conclusion that doesn't exist.
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I am not trying to interpret the NEC, I am trying to read it and follow it. I also am not trying to be argumentative, I am trying to learn.

The NEC says exactly what I stated - 2020 NEC 240.5(B)(3) Extension Cord Sets "Flexible cord used in listed extension cord sets shall be considered to be protected when applied within the extension cord listing requirements." That is a fact, that is EXACTLY what the NEC says, not what I interpret it to say. Do you agree with that?

UL 817 (I have a copy of it) Table 114 Cord Ampacities and Voltage Ratings shows these type of cords to be rated at 13 amps up to 50 feet, and 10 amps over 50 feet. Do you have any disagreement with that (if so, provide the reference)?

The 16 AWG extension cord I have, the common type that anyone can purchase at Home Depot, is labeled at 13 amps (I can provide a photo if needed). That is a fact. Do you have any disagreement with that (if so, state your argument)?

The fact that the plug is rated at 15 amps has no impact on any of that. If it did, what if you put a NEMA 5-50R plug on it - would it then be rated at 50 amps? If you disagree with that please provide me with the NEC article reference to support your argument.

I know what 2020 NEC 240.5(B)(4) says - and it applies to field assembled cord sets, not to manufactured cord sets - which is the subject of this discussion here. Do you agree with that?

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I think the NEC is pretty clear. As Tom Baker said, I will look at when NEC 240.(B)(3) was added and the NFPA comments for that.
 
To me the phrase "when applied within the extension cord listing requirements" is a reference to the load which may be connected to the cord, not the breaker protecting the receptacle into which it is plugged. Both interpretations (yours and mine) are consistent with the grammatical structure of the sentence. But my interpretation allows such listed cords to actually be used and yours does not (since 13A fused receptacle circuits are AFAIK non-existent).
I know that logical analysis often is not the best tool to apply to understanding the NEC, but in this case the fact that extension cords appear to have been allowed by regulatory authorities for a long time leads me to look for an interpretation the allows that. :)
 
If the manufacturer put a 5-50R molded plug on the the 16 gauge cord it wouldn’t be listed and I don’t think you’d find it at Home Depot. Its listed with the 15 amp plug. The manufacturer has passed liability to the consumer by labeling it 13 amps and the NEC is okay with that because a short circuit on a 15 or 20 amp circuit won’t spontaneously burn up the extension cord and a continuous overload will have been caused by the consumer ignoring the manufacturers instructions for loading.
 
hotneutral said:
If the manufacturer put a 5-50R molded plug on the the 16 gauge cord it wouldn’t be listed and I don’t think you’d find it at Home Depot. Its listed with the 15 amp plug. The manufacturer has passed liability to the consumer by labeling it 13 amps and the NEC is okay with that because a short circuit on a 15 or 20 amp circuit won’t spontaneously burn up the extension cord and a continuous overload will have been caused by the consumer ignoring the manufacturers instructions for loading.
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I agree, as I stated earlier in this thread the NEC doesn't really care about a manufactured extension cord, the section relating to them in the entire 1000 page book is a mere 22 words. They've punted anything beyond what you've stated to the NRTL that lists the cord.
 
Okay I did not read everything closely so I am wondering what the application is in the scenario you are asking. Is it for a motor? If so then the overload protection in the motor is protecting the cord from overload while the breaker is protecting it against short circuit and ground fault.

If this is not field assembled then the manufacturer has had the assembly tested and it is listed as such. I am assuming the load on the cord is not more than 13 amps. Otherwise Imo there is enough info given by everyone where it shows this is not an issue.
 
If you can't find something in the NEC, as in not covered, then the NEC has nothing to do with it.
 
Dennis Alwon said:
Okay I did not read everything closely so I am wondering what the application is in the scenario you are asking. Is it for a motor? If so then the overload protection in the motor is protecting the cord from overload while the breaker is protecting it against short circuit and ground fault.

If this is not field assembled then the manufacturer has had the assembly tested and it is listed as such. I am assuming the load on the cord is not more than 13 amps. Otherwise Imo there is enough info given by everyone where it shows this is not an issue.
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The title of this thread says "extension cords".
 
GoldDigger said:
To me the phrase "when applied within the extension cord listing requirements" is a reference to the load which may be connected to the cord, not the breaker protecting the receptacle into which it is plugged. Both interpretations (yours and mine) are consistent with the grammatical structure of the sentence. But my interpretation allows such listed cords to actually be used and yours does not (since 13A fused receptacle circuits are AFAIK non-existent).
I know that logical analysis often is not the best tool to apply to understanding the NEC, but in this case the fact that extension cords appear to have been allowed by regulatory authorities for a long time leads me to look for an interpretation the allows that. :)
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This is a perfect summation of the debate.

The OP is looking for someone to agree with his interpretation and if he hasn’t gotten it by 30+ posts, it’s probably not gonna happen.
 
Mr Reizner: I have not seen a post about extension cords sets on the forum (to my knowledge).
What is the concern with them?
Also, I do not feel that extension cords requirements belong in the scope of the NEC. The NEC is for premise wiring.
 
Jim Reizner said:
when applied within the extension cord listing requirements.
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You answered it right there.

use the cord within the limits. Protection is there. A fault isn’t going to be 14 amps.
It’s going to be a quick amp spike and the 20 OCPD will trip. The cord can handle a quick spike in amps for a fault.
 
It looks clear to me 245 B 3 (2020) allows extension cords used in accordance with their listing to be protected by the circuit they are connected to with the provided attachment plug

Fixture wires are permanently connected and the code allows 18 gage to be 50 feet long and protected by a 15 or 20 amp circuit.


It looks clear to me that the end user is responsible for the load connected to the extension cord or the fixture wires to see that they are not overloaded.

They have concluded that the smaller wire is large enough to operate the overcurrent device on a short
 
Dennis Alwon said:
yes and it has also mentioned cord sets.... Honestly knowing more of the situation would be better. I have seen motors connected with cord and plug. Isn't that a cord set
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After 40 posts IMO we're not discussing anything other than an extension cord.
 
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