Commercial Kitchen Sub Panel

[tdgates]

After working all day I'm a little groggy and need a second opinion. I feel like I'm missing something obvious.

(Moderator: Sorry for the double post, I hit a short cut on accident).

I'm working in a building that is soon to be a commercial kitchen... panel doesn't have enough spaces. I want to install a sub panel for:

4 ovens @ 11kw each / 208 / 1.73 (3 phase)=122.2 amps
1 food processor @ 7.5 amps
1 hot plate @ 3 amps
____________________________________________________
=132.7 amps

132.7 amps * 65% (table 220.56) = 86.3 amps

Assuming service is big enough (it is), all I need is a 100 amp breaker to feed 100 amp (or larger) sub panel.

What do you think? It just doesn't seem right. Maybe because there's a 132 amp load on a 100 amp panel. Am I forgetting something?

Thanks for the help.

 

[hurk27]

After working all day I'm a little groggy and need a second opinion. I feel like I'm missing something obvious.

(Moderator: Sorry for the double post, I hit a short cut on accident).

I'm working in a building that is soon to be a commercial kitchen... panel doesn't have enough spaces. I want to install a sub panel for:

4 ovens @ 11kw each / 208 / 1.73 (3 phase)=122.2 amps
1 food processor @ 7.5 amps
1 hot plate @ 3 amps
____________________________________________________
=132.7 amps

132.7 amps * 65% (table 220.56) = 86.3 amps

Assuming service is big enough (it is), all I need is a 100 amp breaker to feed 100 amp (or larger) sub panel.

What do you think? It just doesn't seem right. Maybe because there's a 132 amp load on a 100 amp panel. Am I forgetting something?

Thanks for the help.

yes that these loads will most likely be all on at the same time, so diversity goes out the window

I have had to up size service because of these caculations being used, while in most part they will work, but you have to look at how the workers will use the equipment, if they plan on firing up all the ovens then you got a problem, I have learned to over size a kitchen panel be cause future loads will get added.

 

[kwired]

yes that these loads will most likely be all on at the same time, so diversity goes out the window

I have had to up size service because of these caculations being used, while in most part they will work, but you have to look at how the workers will use the equipment, if they plan on firing up all the ovens then you got a problem, I have learned to over size a kitchen panel be cause future loads will get added.

If you fire up all the ovens you will not draw continuous 44Kw. They will cycle on and off as needed to maintain temperature. You still do need to take some consideration into how equipment will be used. Table 220.56 gives you minimum values you can always go larger.

You used the 6 and over appliances factor of 65%. The two small loads you have are pretty small compared to the 4 ranges. I would not even consider them and use 4 appliances at 80% (still use 132 amps however)This leaves you with 105.6 amps I would recommend at least 110 amp feeder - but would probably actually install 125 amp feeder. Or better yet find a way to fit the ovens in the service panel that is full and move some smaller loads into a sub panel.

 

[LarryFine]

I want to install a sub panel for:

4 ovens @ 11kw each / 208 / 1.73 (3 phase)=122.2 amps
1 food processor @ 7.5 amps
1 hot plate @ 3 amps

I suggest relocating the smallest circuits to a sub-panel first, and place the large loads in the existing panel.

The sub-panel's breaker and feeder can end up being much smaller that way.

 

[tdgates]

Thanks

Thanks

Thanks guys, for the very helpful information and suggestions.

I did end up putting the small loads on the sub panel and the ovens in the main panel. It's a better installation.

Todd