Can I permanently cord and plug a panelboard? Do I even want too?

[Cow]

I'm working on a project right now with a few plc's, camera, and weighing systems among other things. Not a lot of 120v load, I'm estimating less than 25 amps or so.

Rather than trying to install several smaller computer tower style UPS systems in front of every component, I'd like to propose using one UPS to then feed a small panelboard I could take dedicated circuits out of. Problem is, like the title mentioned, most of these UPS' are cord and plug under 3000va. I have a Liebert quoted to me in the right size, with a hardwired input, but a receptacle output. We are only looking to carry the load on the UPS momentarily through brownouts and similar, and do not need any significant run time after that. Even if the UPS shut down two minutes later, that would be fine.

It seems bumping up to 4-5000va, gets me the hardwired option for the major brands(Liebert and APC), but adds significantly to the cost. The only hardwired option I've seen is a Tripp Lite, I'm just not too familiar with the brand.

https://www.amazon.com/SMART-3KVA-1...220&sr=8-10&keywords=tripp+lite+UPS+hardwired

Thoughts?

 

[kwired]

I'm working on a project right now with a few plc's, camera, and weighing systems among other things. Not a lot of 120v load, I'm estimating less than 25 amps or so.

Rather than trying to install several smaller computer tower style UPS systems in front of every component, I'd like to propose using one UPS to then feed a small panelboard I could take dedicated circuits out of. Problem is, like the title mentioned, most of these UPS' are cord and plug under 3000va. I have a Liebert quoted to me in the right size, with a hardwired input, but a receptacle output. We are only looking to carry the load on the UPS momentarily through brownouts and similar, and do not need any significant run time after that. Even if the UPS shut down two minutes later, that would be fine.

It seems bumping up to 4-5000va, gets me the hardwired option for the major brands(Liebert and APC), but adds significantly to the cost. The only hardwired option I've seen is a Tripp Lite, I'm just not too familiar with the brand.

https://www.amazon.com/SMART-3KVA-1...220&sr=8-10&keywords=tripp+lite+UPS+hardwired

Thoughts?

Not your application but mobile homes can have the supply be cord and plug - and it typically supplies a panelboard.

How is the factory cord on your UPS terminated? If via a standard KO size it maybe is intended to be able to remove the cord and hard wire it?

 

[sameguy]

Hotels have the PTAC cord and plug.
No code book, you are in a supervised, qualified maintenance, etc., so I'm going with yes you can and your other question I'll say sounds like you do.
If you have something plugged in, yet no potential is present, is it temporary or permanent (90days) iirc.?

 

[winnie]

You cannot use flexible cord as a substitute for permanent building wiring, but you are allowed to plug in a piece of equipment on essentially a permanent basis.

Does an 'inlet' type device create a suitable boundary between the 'permanent building wiring' and the 'equipment flexible cord' so that you could 'plug in' the output of the UPS?

-Jon

 

[electrofelon]

You cannot use flexible cord as a substitute for permanent building wiring, but you are allowed to plug in a piece of equipment on essentially a permanent basis.

I've always hated that "substitute for permanent wiring" clause. I know what they intend, to disallow say wiring a house with SO instead of Romex, but we can use it for things that are "permanent". I think the wording could be better.

 

[david]

Rather than trying to install several smaller computer tower style UPS systems in front of every component, I'd like to propose using one UPS to then feed a small panelboard I could take dedicated circuits out of.

I would think a cord and plug would not be compliant with the panelboard application,

Also would consider if the UPS tied to a panelboard derives it's neutral and becomes a SDS since it is now part of the building wiring system

https://www.ecmweb.com/content/ups-stands-firm-ground

 

[Coppersmith]

Not your application but mobile homes can have the supply be cord and plug - and it typically supplies a panelboard.

Travel trailers also have a panelboard that is plugged in.

And carnivals.

These are temporary situations though.

 

[kwired]

You cannot use flexible cord as a substitute for permanent building wiring, but you are allowed to plug in a piece of equipment on essentially a permanent basis.

Does an 'inlet' type device create a suitable boundary between the 'permanent building wiring' and the 'equipment flexible cord' so that you could 'plug in' the output of the UPS?

-Jon

If the UPS is considered something that needs frequent interchange then cord and plug on both sides of it should be acceptable.

I would think a cord and plug would not be compliant with the panelboard application,

Also would consider if the UPS tied to a panelboard derives it's neutral and becomes a SDS since it is now part of the building wiring system

https://www.ecmweb.com/content/ups-stands-firm-ground

Isn't it part of premises wiring whether it is a SDS or not?

 

[Coppersmith]

If the UPS is considered something that needs frequent interchange then cord and plug on both sides of it should be acceptable.

I have UPS's on my computer and DVR. They do require replacement every 2-3 years. I think you're on to something.

 

[david]

If the UPS is considered something that needs frequent interchange then cord and plug on both sides of it should be acceptable.



Isn't it part of premises wiring whether it is a SDS or not?

In my opinion yes, my point is you do not usually bond the neutral for individual ups that back up say, a door opener for a person with a disability or one for someones PC, but a UPS that backs up critical branch circuits (building wiring) from a panel would seem to indicate cord and plug connection of the UPS and panel needs to use chapter 3 methods

 

[LarryFine]

To the original question, we often say that the NEC stops at the receptacle. In this vein, I often add a wall-mounted TV receptacle by installing two old-work boxes, one behind the TV and one matching the height of the existing receptacles, joined by 14-2 NM.

The upper box receives a standard or a recessed (clock) receptacle, and the lower one a blank plate with a 1/2" hole with a knotted power cord and plug. The plug can be plugged into the same surge strip as the rest of the system or any nearby receptacle.

So, does the NEC either regulate or prohibit the above installation in any way, or is it merely an extension cord that happens to use wiring methods that are normally used in NEC-compliant installations? If it's okay, so is the OP's panel-fed-by-cord proposal.