120V, 20A equipment arrived with 250V, 20A inlet - does this meet code?

Junkman

Member
Location
North FL
Occupation
Facility Manager
I just received a large piece of equipment that is rated a 120V, 20A circuit. On the back, it has a 250V, 20A flanged L6-20P inlet, HBL2325. The manufacturer wires machines for either 120V or 208V, as requested by the end user, but uses the same plug on the back of all units. The manufacturer asks the end user to construct a cord that goes from an L6-20R cord connector to a 5-20p or L5-20P, depending on what receptacle type we have.

So, my questions are these:
1) Does putting an L6-20P inlet on a 120V piece of equipment meet NEC?
2) 2020 NEC Article 406.8, noninterchangeability, says that “receptacles, cord connectors, and attachment plugs shall be constructed such that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended.” Does this apply to the equipment? Or just to the construction of the receptacles and plugs? If not, what article would apply?
3) This setup would allow someone to connect this to 208V, 20A power in the future, which is a safety hazard. What part of NEC should prohibit this?
4) If we make a cord that has L6-20R on one end and 5-20p on the other, someone could use this cord in the future to try to plug a 208V item in to a 120V receptacle. Does this cord violate NEC?
5) Is it allowable, even if a bad idea, to use L6-20 components on a 120V circuit because they have a higher voltage rating? It says 250V, but doesn't provide a minimum.

I really appreciate everyone's help. I have enjoyed finding answers to many questions on the forum over the years.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
IMO the NEC does not apply directly to the cord and plug piece of equipment. What is this thing anyway?
 

GoldDigger

Moderator
Staff member
1) Does putting an L6-20P inlet on a 120V piece of equipment meet NEC?
2) 2020 NEC Article 406.8, noninterchangeability, says that “receptacles, cord connectors, and attachment plugs shall be constructed such that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended.”
I interpret "device" here as referring to the "recptacles, cord connectors, and attachment plugs", not the utilization equipment to which they are attached.
The inlet on the equipment is rated for 250V and will in fact not accept a receptacle that is rated for 120 volts. Nothing is said, IMHO, about what voltages may be present on the wires, as long as those voltages are less than or equal to the rated voltage of the inlet.

Is this good design? Probably not, for reasons some of which you have listed. But still code compliant.
 

480sparky

Senior Member
Location
Iowegia
Maybe when they start letting the smoke out of the machines when the maintenance man sees a 240v inlet and wires it accordingly, they manufacturer will wise up when they get enough warranty calls.
 

GoldDigger

Moderator
Staff member
Maybe when they start letting the smoke out of the machines when the maintenance man sees a 240v inlet and wires it accordingly, they manufacturer will wise up when they get enough warranty calls.
Or at a minimum attach a durable plaque next to the inlet stating the configured voltage of the machine.

Computer equipment usually uses an inlet which can be used with either a 120V or 250V cord set, and in most but not all cases the power supply fed by the output will accept any voltage in that range. In some cases, however, especially with older equipment, there is a switch which must be set to correspond to the supplied voltage.
 
Computer equipment usually has a C13 or C19, but those are expected to be voltage-agnostic; an L6-20 is expected to have 208/240 volts on it.

I take it this beast is not listed. Is it?
If nothing else, I'd firmly attach the cord to the device so it doesn't randomly go walkabout.
 

FionaZuppa

Senior Member
Location
AZ
Or at a minimum attach a durable plaque next to the inlet stating the configured voltage of the machine.
+1, get some "Wired For 120v 60Hz" plates made and rivet them on.

rest for OP
The plug/recept itself does not matter, it only carries a rating, and as long as you don't violate the rating you should be good. You could essentially wire a home using CAT-III 1kV wiring as long as the ampacity rating is proper.

Some ask "why would they do that?" on this equip, because maybe if you making a boat load of gear that is wired 120v or 240v, using one part for all makes sense.

Just wondering though, OP says "is wired for 120v", does that mean 240v is a wired option? If so then why not use the more efficient 240v?
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
+1, get some "Wired For 120v 60Hz" plates made and rivet them on.

rest for OP
The plug/recept itself does not matter, it only carries a rating, and as long as you don't violate the rating you should be good. You could essentially wire a home using CAT-III 1kV wiring as long as the ampacity rating is proper.

Some ask "why would they do that?" on this equip, because maybe if you making a boat load of gear that is wired 120v or 240v, using one part for all makes sense.

Just wondering though, OP says "is wired for 120v", does that mean 240v is a wired option? If so then why not use the more efficient 240v?
Because 240 is not 208?
 
Interesting that their L6-20 is a straight blade device. I didn't know that such existed.
It doesn't- "L" means locking. The picture on that page shows a locking connector, the text says "straight blade". They'll probably make whatever you want, sensible or not.

(A little digging says "Iron Box holds multiple UL files for power supply cords, wire harnesses, and PDU whips.")
 

Jamesco

Senior Member
Location
Iowa
Interesting that their L6-20 is a straight blade device. I didn't know that such existed.
Applications: Adapt a L6-20P straight blade plug to fit a 5-20R outlet
Yeah, that caught my eye as well, though I figured it must be a misprint.
L6-20P, L stands for locking.

This makes more sense:
Applications: Adapt a L6-20P to straight blade plug to fit a 5-20R outlet.
The cord adapter does that. And if true is UL Listed.
 

jusme123

Senior Member
Location
NY
I think 406.8 is clear, and it would be a violation. This is a field fabricated cord and must comply to NEC.
 
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FionaZuppa

Senior Member
Location
AZ
Because 240 is not 208?
You think it's 120v 1ph, or, 208 3ph? Likely not the case. More likely it's 1ph equip.

Still does seem odd, "a large piece of equip" and it only needs a 120-20A-1ph power?
Might be large in size, but very small on power.

Looks like OP found already made cord with cap ends that will work? Problem solved.
 
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