Use of Portable Cord Sets (Extension Cords) Over 90 Days

Joseito

Member
Location
Illinois
Hello fellow Forum members,

I know the NEC limits flexible cord use to 90 days for Christmas Decorations, Carnivals, etc, and for the duration of temporary construction or work, but there is no other place in the NEC that limits how long they can be used for connection of portable equipment, and the other allowable uses. I know the NEC states that flexible cords and cables shall not be used in lieu of permanent wiring, but if an extension cord is being used for one of their acceptable uses, where in the NEC does it states for how long that extension cord could be used? I've read multiple comments stating that they have seen extension cords powering portable equipment at an industrial plant for over 5 years and that that is not acceptable, etc, but the NEC would not prohibit that.. or does it?

Thanks everyone!
 

Joseito

Member
Location
Illinois
NEC Article 400.7, has a list of "Uses Permitted". The one I see the most if the use of extension cords to plug portable appliances, or utilization equipment to facilitate frequent interchange. The NEC does not define how frequent is frequent, nor does it define what is considered to be "portable". So if someone is using an extension cord to power an appliance or piece of equipment, my question is where in the NEC does it say that this can not be done for longer than X days.
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
I once did a small food production facility that had a room with about 30 large production style dehydrators in it, each requiring 25A at 208V 3 phase. I had planned on hard wiring everything and putting disconnect switches on the side of each one, but the customer EE wanted them all connected with SO cord to wall mounted twist-lock receptacles, which then precluded the need for disconnects.The dehydrators, despite being the size of 3 household refrigerators and weighing almost a ton, were on steel casters, so his claim was that they were "portable" and thereby using cords and caps into receptacles was an acceptable use. I obliged and the AHJ accepted it, so I was wrong.
 

FionaZuppa

Senior Member
Location
AZ
NEC Article 400.7, has a list of "Uses Permitted". The one I see the most if the use of extension cords to plug portable appliances, or utilization equipment to facilitate frequent interchange. The NEC does not define how frequent is frequent, nor does it define what is considered to be "portable". So if someone is using an extension cord to power an appliance or piece of equipment, my question is where in the NEC does it say that this can not be done for longer than X days.
Perhaps it's in another NFPA book?
 

retirede

Senior Member
Location
Illinois
I once did a small food production facility that had a room with about 30 large production style dehydrators in it, each requiring 25A at 208V 3 phase. I had planned on hard wiring everything and putting disconnect switches on the side of each one, but the customer EE wanted them all connected with SO cord to wall mounted twist-lock receptacles, which then precluded the need for disconnects.The dehydrators, despite being the size of 3 household refrigerators and weighing almost a ton, were on steel casters, so his claim was that they were "portable" and thereby using cords and caps into receptacles was an acceptable use. I obliged and the AHJ accepted it, so I was wrong.
But if the cords were hard-wired to the equipment, they’re not extension cords??
 

S'mise

Senior Member
Location
Michigan
I don't think you'll find it in the nec other than 110.3b not follow manufacture instructions and listings.

The power cord set standard can be found under UL 817

You might have better luck look at osha requirements.
 

Joseito

Member
Location
Illinois
I don't think you'll find it in the nec other than 110.3b not follow manufacture instructions and listings.

The power cord set standard can be found under UL 817

You might have better luck look at osha requirements.


OSHA actually doesn't say anything at all in terms of time limits, other than the 90 days for Christmas, etc. OSHA does say extension cords, like electric equipment, shall be used in accordance with their listing and labeling, but the instructions or listing and labeling do not limit how long a piece of equipment could be connected to an outlet by using an extension cord. I don't think there's any place in the NEC or elsewhere that says that extension cords should not be used to power equipment longer than X days.
 
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