I posted this in the General Forum, but did not get any feedback. Perhaps, this is the forum I should have posted in.
I need advice for sizing some transformers. I have a test kitchen that has two cooking sections in the same room. One section will have (4) 208v / 3Ph 17KW electric fryers. The second section has (3) of the same fryers and (2) 208 / 1 Ph / 2700 watt sandwich grilles and (1) 9KW / 3Ph griddle. In addition to this is a walk-in freezer at 12KW (208v / 1Ph) and a 50 gallon water heater (3500 w / 1Ph) (standard residential)
This is the set up: Each "section" as I call it is actually a portable wall with a vent hood, suppression system, and the electrical outlets for the above listed appliances already installed. On the other side of this wall is a 225 amp MLO / 3 Ph Square D QO panel. All I am required to do is feed the panels, plus the branch circuits for the freezer, exhaust fan and water heater.
The MDP is 480V.
Based on table 220.56 I have calculated the following:
Fryers 7 x 17KW = 119,000
Griddle 1 x 9KW = 9,000
Sandwich grill 2 x 2.7KW = 5,400
Freezer 1 x 12KW = 12,000
Water Heater 1 x 4.5KW = 4,500
Exhaust Fan 1 x 1.5KW = 1,500
Total 151,400 x 65% (6+ appliances) = 98,410
98,400/ (208 x 1.732) = 273 A
Based off of my calculations it seems a 112.5 KVA transformer would be sufficient. Am I missing something, or have I calculated incorrectly? It just seems as though all of these appliances should require a larger transformer. Also, I realize that based on 220.56 I can use a 65% demand factor, but I know that these units will all be coming on at once and I would assume the fryers will cycle at similar rates. I just don't want to under size the transformer.
I have also considered installing a 75KVA and 112.5 KVA transformer and setting a 200 amp disconnect for one wall and a 225 amp panel with feed-thru lugs, so the busbar in the 225 amp could supply the exhaust fan, water heater and freezer and the lugs could supply the second wall. I have considered this simply due to availability considering that the customer wants to do this as soon as possible and smaller panels and transformers are more readily available. Thoughts?
Thank you in advance for your help.
I need advice for sizing some transformers. I have a test kitchen that has two cooking sections in the same room. One section will have (4) 208v / 3Ph 17KW electric fryers. The second section has (3) of the same fryers and (2) 208 / 1 Ph / 2700 watt sandwich grilles and (1) 9KW / 3Ph griddle. In addition to this is a walk-in freezer at 12KW (208v / 1Ph) and a 50 gallon water heater (3500 w / 1Ph) (standard residential)
This is the set up: Each "section" as I call it is actually a portable wall with a vent hood, suppression system, and the electrical outlets for the above listed appliances already installed. On the other side of this wall is a 225 amp MLO / 3 Ph Square D QO panel. All I am required to do is feed the panels, plus the branch circuits for the freezer, exhaust fan and water heater.
The MDP is 480V.
Based on table 220.56 I have calculated the following:
Fryers 7 x 17KW = 119,000
Griddle 1 x 9KW = 9,000
Sandwich grill 2 x 2.7KW = 5,400
Freezer 1 x 12KW = 12,000
Water Heater 1 x 4.5KW = 4,500
Exhaust Fan 1 x 1.5KW = 1,500
Total 151,400 x 65% (6+ appliances) = 98,410
98,400/ (208 x 1.732) = 273 A
Based off of my calculations it seems a 112.5 KVA transformer would be sufficient. Am I missing something, or have I calculated incorrectly? It just seems as though all of these appliances should require a larger transformer. Also, I realize that based on 220.56 I can use a 65% demand factor, but I know that these units will all be coming on at once and I would assume the fryers will cycle at similar rates. I just don't want to under size the transformer.
I have also considered installing a 75KVA and 112.5 KVA transformer and setting a 200 amp disconnect for one wall and a 225 amp panel with feed-thru lugs, so the busbar in the 225 amp could supply the exhaust fan, water heater and freezer and the lugs could supply the second wall. I have considered this simply due to availability considering that the customer wants to do this as soon as possible and smaller panels and transformers are more readily available. Thoughts?
Thank you in advance for your help.