Is it Legal to De Rate a 100 Panel to 20A?

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DesMoines, Washington
We are required to use Panels with Bolt On Breakers. Problem is those models usually come in at 100 A. We only need 20 A at the location so we're supplying it with #6 AWG conductors.

There will be only 2 breakers in the Panel. Can we put a Placard on the Panel saying 20 A service only? To keep someone else down the line from popping in more circuits? Or is this illegal?

Thank you in advance.
 
I don't see a problem with using a 60a ocpd on a sub panel rated 100 amps I believe your ok as long as you don't feed it with a more.then 100 amps if I'm wrong someone here will correct me but if you run #6s I would fuse it at the amperage rated for that conductor if it were my job

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Perfectly legal and no signage required. Whoever goes in it in the future should find it self explanatory.
 
How long isn't he the run if your going to to run #6s anyway it might not cost that much more to just feed it with the correct size conductors anyhow

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Installer said:
Its a Square D panel without a main. So my plan is to put a 20 A disconnect switch ahead of it. Is that okay?
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I would install a 20A 2-pole breaker as a back fed main device. Square D has breaker hold down clips just for this reason.
 
I'm not sure if this will save any money, but there are DIN rail mounted breakers you could use. Not bolt-on technically, but they are securely mounted on the rail. You could then use a much smaller cabinet.
 
Just curious, what is the best SO cord for this application. It would be SE, USE, right? For 120/240 VAC service ( 2 Hots and a Neutral) Can anyone recommend a specific brand or part number?
Now don't laugh, maybe I am not under standing the code, do I need an additional conductor besides the 2 Hots and Neutral to bond the metal Disconnect case at one end of the 387' foot run to the one on the other side?
 
Installer said:
Just curious, what is the best SO cord for this application. It would be SE, USE, right? For 120/240 VAC service ( 2 Hots and a Neutral) Can anyone recommend a specific brand or part number?
Now don't laugh, maybe I am not under standing the code, do I need an additional conductor besides the 2 Hots and Neutral to bond the metal Disconnect case at one end of the 387' foot run to the one on the other side?
Click to expand...
Is this some sort of temporary setup? Because you know that you can't use SO cord for permanent wiring, right?
 
We do this on Chik-Fil-A restaurants .... they have a 20-space MLO panel with roughly six 20A circuits, all fed by a 20A breaker from the MDP. It’s the isolated ground circuits for POS.


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Installer said:
i didn't mean to say SO, I was thinking SE vice USE, also Direct Burial--didnt sleep well last night
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Just curious, what is the best DIRECT BURIAL cord for this application. It would be SE, not USE, right? For 120/240 VAC service ( 2 Hots and a Neutral) Can anyone recommend a specific brand or part number?
Now don't laugh, maybe I am not under standing the code, do I need an additional conductor besides the 2 Hots and Neutral to bond the metal Disconnect case at one end of the 387' foot run to the one on the other side?
 
It is necessary to run a wire EGC (Equipment Grounding Conductor) unless you have an electrically continuous metallic raceway that serves the same purpose.
 
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