Power cord set rules

[S'mise]

I know using flexible cords as a substitute for a permanent wiring method is a NEC violation as well as having attaching it to a building.

In an industrial facility last week, I saw numerous truss mounted cooling fans that were using a bunch of IEC type power cord sets zip tied to bridal rings every 8ft or so. The thing I did not like was plugging multiple lengths of these cord sets together in order to reach a receptacle outlet. (40 or 50 feet)

The NEC covers "flexible cords" (Art 400) but types are defined per UL 62 and "power cord sets" per UL 817. This seems to render the above installation as ok because its a UL cord? I cant seem to find anywhere in the UL that prohibits plugging in multiple cord sets together provided the ampacity is not exceeded. Does this sound right to you?

 

[S'mise]

No takers? Let me rephrase the question; Where can I find rules on cord sets like; How many can be plugged together and where/how can they be used? (UL does not seem to mention these things)

What is the definition of attached to building surface? If a cable is ran thru a bridle ring is that not attached? Is it if it is zip tied to the bridle ring?

 

[don_resqcapt19]

I am not sure what you mean by "IEC" style cord sets, but the UL Guide Information for "Cord Sets and Interconnection Cords Certified to IEC Standards(EKVI) says the following.

This category covers cord sets and interconnection cord sets for household and similar general-purpose equipment.
Cord sets and interconnection cords are not intended to be used as a substitute for the fixed wiring of a structure and, hence, are not intended to be fastened in place. Cord sets are rated in volts, amps and watts.

Cord sets and interconnection cords can be furnished in hanked or coiled form. If used in this condition, excessive heating may occur. Therefore, when placed into service, all wrappings should be removed, and the flexible cord should be extended for its entire length.
For information regarding the Flexible Cord Types and their ratings, for the information see the corresponding International Standards as indicated in the International Specifications for cord sets.
These products are intended for distribution and use in areas of the world where IEC Standards are in effect. ...
The basic standard used to investigate products in this category is IEC 60799, "Electrical Accessories - Cord Sets and Interconnection Cord Sets."

If they are cord sets covered by UL 817, that Guide Information is "Cord Sets and Power Supply Cords(ELBZ) and that says:

...Cord sets and power-supply cords are not intended to be used as a substitute for the fixed wiring of a structure and, hence, are not intended to be fastened in place. ...
The basic standard used to investigate products in this category is ANSI/UL 817, "Cord Sets and Power-Supply Cords." ...

It is my opinion that the cords in question are fastened in place and are being used a substitute for the fixed wiring of the structure. Even if these cord sets are not coverd by Article 400, there is a code violation based on 110.3(B).

 

[GoldDigger]

From the NEC and UL point of view, another major possible is the manufacturer's instructions and labeling that accompany the portable cord.
Some will say that they should not be used in series with additional portable cords, while others list length limitations for particular current draws. (The latter are obviously based more on voltage drop than simple conductor ampacity.)
Also out of curiosity, are those shrouded male connectors on the ends of the short cords attached to the motor units? With cord retainers to keep them from unplugging under tension or vibration?
If so, then that manufacturer clearly intended them to be plugged into cord-mounted receptacles rather than into fixed receptacles.
Are the male ends the type known as "IEC", as the term is used to describe standard three wire connectors used on desktop computers and as the input connector to power supplies, etc?
If, then the matching cords will more or less by definition be power cord assemblies whether they are furnished with the fans or not, since they will not mate with a standard NEMA plug as used to connect to building wiring receptacles.
In that case the appropriate question is just how far those cords can go without becoming a substitute for fixed wiring. I am inclined at least to limit the length to one cord of whatever length rather than a series string of cords. Once you get to the level where both cord ends are NEMA standard (either straight or locking), I think you are out of the realm of power cords and into flexible cords with the accompanying NEC limitations.

 

[S'mise]

From the NEC and UL point of view, another major possible is the manufacturer's instructions and labeling that accompany the portable cord. Manufacture does not address this in their instructions
Some will say that they should not be used in series with additional portable cords, while others list length limitations for particular current draws. (The latter are obviously based more on voltage drop than simple conductor ampacity.) The UL talks about ampacity, wattage and VD of the cord set
Also out of curiosity, are those shrouded male connectors on the ends of the short cords attached to the motor units? With cord retainers to keep them from unplugging under tension or vibration? Yes
If so, then that manufacturer clearly intended them to be plugged into cord-mounted receptacles rather than into fixed receptacles. Not necessarily, the power cords have a regular cord cap (nema5-15) on one end and an IEC C13 (female) on the other end
Are the male ends the type known as "IEC", as the term is used to describe standard three wire connectors used on desktop computers and as the input connector to power supplies, etc? Yes exactly, IEC C13 and C14 which I believe are meant to be used to extend the speed switch not to extend power
If, then the matching cords will more or less by definition be power cord assemblies whether they are furnished with the fans or not, since they will not mate with a standard NEMA plug as used to connect to building wiring receptacles. They do mate with a NEMA 5-15 (regular coed cap) to a .female IEC end These cable types are listed in the instructions
In that case the appropriate question is just how far those cords can go without becoming a substitute for fixed wiring. I am inclined at least to limit the length to one cord of whatever length rather than a series string of cords. Once you get to the level where both cord ends are NEMA standard (either straight or locking), I think you are out of the realm of power cords and into flexible cords with the accompanying NEC limitations.

I believe if its a UL listed cord set (which they are) it's still under the UL realm, but as Don says, they have similar language about "using as a substitute for permanent wiring methods"

 

[S'mise]

covered by UL 817, that Guide Information is "Cord Sets and Power Supply Cords(ELBZ) and that says:...not intended to be uses as substitute...It is my opinion that the cords in question are fastened in place and are being used a substitute for the fixed wiring of the structure. Even if these cord sets are not coverd by Article 400, there is a code violation based on 110.3(B).

Thanks Don, I missed where the UL 817 said that.
I guess you could cite 110.3(B) Because the cord set is not being used per the UL listings. In-spite the fact the fan manufacture instructions do not address anything about wiring methods.

 

[don_resqcapt19]

Thanks Don, I missed where the UL 817 said that.
I guess you could cite 110.3(B) Because the cord set is not being used per the UL listings. In-spite the fact the fan manufacture instructions do not address anything about wiring methods.

The information that I cited was not from UL 817, it was from the Guide Information, also known as the White Book.

Actually, it is my opinion that the only instructions that are really listing and labeling instructions are those found in the White Book (guide information that I cited) or the listing standard.

I know that UL says otherwise, but I don't see the instructions that are provided by the manufacturer with the equipment as listing and labeling instructions that you are required to follow per 110.3(B).

 

[S'mise]

If there are separate UL listings for the cord set and the appliance itself (in this case a fan) shouldn't they each comply with their perspective rules? It's fair to say that the fan manufacture is not the same company as the cord manufacture.

Correct me if I'm wrong, but I understand the UL 817 as covering full details of cord sets (164 pages) while the UL White book is more of a general reference guide, giving only a brief listing description. (perhaps a few paragraphs on the listing).

 

[don_resqcapt19]

If there are separate UL listings for the cord set and the appliance itself (in this case a fan) shouldn't they each comply with their perspective rules? It's fair to say that the fan manufacture is not the same company as the cord manufacture.

Correct me if I'm wrong, but I understand the UL 817 as covering full details of cord sets (164 pages) while the UL White book is more of a general reference guide, giving only a brief listing description. (perhaps a few paragraphs on the listing).

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I see the standard as the required design and testing information for the cord set. The white book is more like the installation instructions and requirements. In my opinion the white book is the 110.3(B) rules.

 

[petersonra]

I know using flexible cords as a substitute for a permanent wiring method is a NEC violation as well as having attaching it to a building.

In an industrial facility last week, I saw numerous truss mounted cooling fans that were using a bunch of IEC type power cord sets zip tied to bridal rings every 8ft or so. The thing I did not like was plugging multiple lengths of these cord sets together in order to reach a receptacle outlet. (40 or 50 feet)

How is it a substitute for a permanent wiring method?

In any case the rule says the cord can't be attached to a building surface. I don't see how a structural member is a building surface.

I am not thrilled with the idea of stringing cords together, but I don't see anywhere it is specifically banned in the code, although those that do not like cords for whatever reason can no doubt concoct a rule that might say so if you look at it sideways.

 

[don_resqcapt19]

How is it a substitute for a permanent wiring method?

Code is not real clear, but if you are using an extension cord for a permanently mounted piece of equipment and that extension cord is left in place all the time, that is a cord that is being used as a substitute for a permanent wiring method.

In any case the rule says the cord can't be attached to a building surface. I don't see how a structural member is a building surface.

The White Book says the cord cannot be fastened in place. Is the fact that it is supported by "J" hooks the same as being fastened in place.

I am not thrilled with the idea of stringing cords together, but I don't see anywhere it is specifically banned in the code, although those that do not like cords for whatever reason can no doubt concoct a rule that might say so if you look at it sideways.

I thought there was a section in the White Book that said you can't daisy chain extension cords, but I didn't find it.

 

[S'mise]

How is it a substitute for a permanent wiring method? Allowing someone to run excessive lengths of extension cords instead of installing an outlet reasonably near the point of use is about the best example I can think of

In any case the rule says the cord can't be attached to a building surface. I don't see how a structural member is a building surface. Zip tying to trusses, along I-beams and down columns sure sounds like its attached to me. even if offset by bridle rings or J-hooks

I am not thrilled with the idea of stringing cords together, but I don't see anywhere it is specifically banned in the code, although those that do not like cords for whatever reason can no doubt concoct a rule that might say so if you look at it sideways.

I am OK with it within reason, but lets be honest; running cords 50ft is hack work. I just wanted to know what the UL rules have to say on the matter. Thanks to Don I think I have a better grasp now.

 

[petersonra]

I am OK with it within reason, but lets be honest; running cords 50ft is hack work. I just wanted to know what the UL rules have to say on the matter. Thanks to Don I think I have a better grasp now.

I am not thrilled with the idea of daisy chaining extension cords for this kind of thing. It does not look nice.

Whether it actually violates the NEC is a different issue.

 

[S'mise]

I am not thrilled with the idea of daisy chaining extension cords for this kind of thing. It does not look nice.
Whether it actually violates the NEC is a different issue.

Agreed. At this point 110.3(b) seems to be the only NEC violation. I expect it will be cleared up in future code cycles where UL cord sets will be considered as flexible cables covered by article 400.

The intent of article 400 forbids the use of extension cords like this.

 

[don_resqcapt19]

Agreed. At this point 110.3(b) seems to be the only NEC violation. I expect it will be cleared up in future code cycles where UL cord sets will be considered as flexible cables covered by article 400.

The intent of article 400 forbids the use of extension cords like this.

You have time to submit a public input (formally known as a proposal). Online public inputs have to be submitted prior to 5pm EST , Nov. 7, 2014.

 

[S'mise]

You have time to submit a public input (formally known as a proposal). Online public inputs have to be submitted prior to 5pm EST , Nov. 7, 2014.

Think I'll do that. I'll also propose putting an exception to 300.11(C) that would allow low voltage communication cables to be tie wrapped to conduit.