Flexible cord sizing

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Steelhead

Senior Member
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Southeastern Wisconsin
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Industrial Maint/Journeyman
When sizing flexible cord I'm not seeing anything in the code that states you need to size the cord at 125% of the FLA of the equipment you are attaching the cord and attachment plug to. We have several pieces of equipment in our plant that are connected with a cord and attachment plug where the cord is sized less than 125% of the nameplate FLA. I know that branch circuits for specific applications and applications where there is a continuous load that the conductors will need to be sized at 125%, but what about flexible cord?
 
Steelhead said:
When sizing flexible cord I'm not seeing anything in the code that states you need to size the cord at 125% of the FLA of the equipment you are attaching the cord and attachment plug to. We have several pieces of equipment in our plant that are connected with a cord and attachment plug where the cord is sized less than 125% of the nameplate FLA. I know that branch circuits for specific applications and applications where there is a continuous load that the conductors will need to be sized at 125%, but what about flexible cord?
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IMO, the ampacity requirements apply to cords as well as single conductors. There is nothing that says it does not.
 
It might be easier to understand your question if you put it in context. What sort of application? For example, flexible cord can be used in place of hard piping if the pipe were to be subject to vibration. If the equipment/machine is on wheels, flex cord can be used. I don't think the intent to allow the use of flex cable means you can undersize it.
 
ValeoBill said:
It might be easier to understand your question if you put it in context. What sort of application? For example, flexible cord can be used in place of hard piping if the pipe were to be subject to vibration. If the equipment/machine is on wheels, flex cord can be used. I don't think the intent to allow the use of flex cable means you can undersize it.
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For example, several years ago we had a reputable electrician install a SOOW 8/4 cord on a plastic material dryer. The nameplate FLA is 41.1A, 480V 3PH. According to 400.5(A)(1) Column A, that cord is only rated for 35A
 
ValeoBill said:
It might be easier to understand your question if you put it in context. What sort of application? For example, flexible cord can be used in place of hard piping if the pipe were to be subject to vibration. If the equipment/machine is on wheels, flex cord can be used. I don't think the intent to allow the use of flex cable means you can undersize it.
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We also have what are called granulators that grind up plastic parts. Nameplate states 24.8A FLA 480V 3PH. Cords installed on these units are SOOW 10/4 and on some units 12/4. Those cords are rated 25A and 20A respectively. These units for sure need to be connected via a cord and plug whereas the material dryer mentioned in my last post could be hard wired; not sure why the electrician chose cord and plug as there isn't any vibration to worry about or a need to move this equipment.
 
don_resqcapt19 said:
Under what rule? They are not branch circuit conductors as those stop at the receptacle.
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An example where SO cord would be part of the branch circuit is cord drops from the ceiling for portable plug connected equipment - for an example look at a kitchen in Costco
 
Portable cord is an often misapplied product by maintenance electricians, they use SO cord as it’s fast, and no knowledge of conduit bending required. Most electricians know that #12 is good for 20 amps and not know there is a separate table in Art 400.
DLO cable is another misapplied product.
 
tom baker said:
Portable cord is an often misapplied product by maintenance electricians, they use SO cord as it’s fast, and no knowledge of conduit bending required. Most electricians know that #12 is good for 20 amps and not know there is a separate table in Art 400.
DLO cable is another misapplied product.
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I agree as I initially didn't realize table 400.5(A)(1) existed.
 
tom baker said:
Portable cord is an often misapplied product by maintenance electricians, they use SO cord as it’s fast, and no knowledge of conduit bending required. Most electricians know that #12 is good for 20 amps and not know there is a separate table in Art 400.
DLO cable is another misapplied product.
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If only the code recognized that as a reason to use cord in lieu of conduit.
 
tom baker said:
An example where SO cord would be part of the branch circuit is cord drops from the ceiling for portable plug connected equipment - for an example look at a kitchen in Costco
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I can agree with that, but in this thread the cord male end is plugged into a receptacle. That type of cord is not a branch circuit conductor...not even sure if it is subject to any rules in the NEC. In general the rules in the NEC stop at the receptacle.
 
Don, what I don’t like is the code has rules for lamp cords, extension cords, gfci on vending machine cord, all for equipment that plugs in.
 
tom baker said:
Don, what I don’t like is the code has rules for lamp cords, extension cords, gfci on vending machine cord, all for equipment that plugs in.
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Yes, I know, and it is my opinion that such rules are invalid as they are completely outside the scope of the code.

A number of cycles ago, one of the panel statements from CMP 2 got it right....the code stops at the outlet. However that is not how the code is written and applied.
 
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