Calculate size of sub panel

ritelec

Senior Member
Location
Jersey
As calculation for sub panel ? Is it based on 125 % of continuos and 100 % non continuos load. As if all these loads will be present at one time.
Even if some loads are receptacle with nothing plugged in or switches aren't on that all loads are not running ?


Thank you.
 

iwire

Moderator
Staff member
Location
Massachusetts
Calculations for a sub panel are done in the same way they are done for a main.

The load for general purpose receptacles in a dwelling unit is a bit tricky as it is based on sq ft.
 

ritelec

Senior Member
Location
Jersey
Ok thanks

In a commercial kitchen. How would the calculation be done.

Based on everything running at once ? If everything was running at one time ?

Thank you.
 

iwire

Moderator
Staff member
Location
Massachusetts
Ok thanks

In a commercial kitchen. How would the calculation be done.

Based on everything running at once ? If everything was running at one time ?

Thank you.
For commercial most folks use 180 vA per duplex receptacle for general purpose outlets. There is some debate if the code requires that.

For dedicated receptacles I would use the load of the equipment it supplies.


As far as counting it all at once, pretty much yes unless you there is a reasonable argument two loads will never run at the same time.
 

ritelec

Senior Member
Location
Jersey
Thank you

I'm trying to make myself feel a bit better about turning down some work.

There's a twenty circ 3 phase food prep panel

Enclosed is it's pic and original directory when installed.


Thinking back on this instead of walking away maybe I could have tried to find receptacles with nothing plugged in and removed them from there breakers or told the owner it was either the new equipment or old and one would not be connected. ??


Although the panel was only pulling 30 amps at ant time that I could see, it would have been needed to be calculated for its load from what the directory says which is about 69 amps. Then there are additionals that aren't in the directory.

Am i correct with this ?
 

topgone

Senior Member
Thank you

I'm trying to make myself feel a bit better about turning down some work.

There's a twenty circ 3 phase food prep panel

Enclosed is it's pic and original directory when installed.


Thinking back on this instead of walking away maybe I could have tried to find receptacles with nothing plugged in and removed them from there breakers or told the owner it was either the new equipment or old and one would not be connected. ??

Although the panel was only pulling 30 amps at ant time that I could see, it would have been needed to be calculated for its load from what the directory says which is about 69 amps. Then there are additionals that aren't in the directory.

Am i correct with this ?
We don't see 3-pole breakers! Does that mean you actually don't have 3-phase loads?
 

ritelec

Senior Member
Location
Jersey
We don't see 3-pole breakers! Does that mean you actually don't have 3-phase loads?
There are no three phase loads in that panel.

But that panel is three phase four wire.

So when I was gong to take a sub panel from that sub panel.
I was going to take out three phase four wire 60 a and not single phase three wire 60 a
 
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