Wiring a Pizzeria have a few questions about shunting an oven

[TNeighbarger]

Given the choice, I recommend the 240v 3ph option. Again, I suggest a separate 3ph panel or disconnect for the oven. You can not use the high-leg 208v to neutral to supply anything, by the way.

Suite, not sweet.

I will go the 240v 3ph option that makes the most sense. The only thing that is going to use the 3ph is the oven so I can set a 3ph panel in the suite and then pull a 1ph sub off of it? To feed the lighting and other circuits or does it make more sense to just use the 3ph panel and make sure I don't have any 1ph circuits on the high leg?

 

[TNeighbarger]

If you've only got single-phase to the bay's panel, you need a phase converter to get 3-phase out of it.

If I pull in the other leg into the suite off of the switch gear I will still need a phase converter? I just need the high leg for the oven

 

[jumper]

If I pull in the other leg into the suite off of the switch gear I will still need a phase converter? I just need the high leg for the oven

No, you will not need a converter then, but all the conductors must be in the same raceway or cable.

You cannot run it separate.

Is the conduit sized big enough to pull another conductor?

 

[jumper]

I will go the 240v 3ph option that makes the most sense. The only thing that is going to use the 3ph is the oven so I can set a 3ph panel in the suite and then pull a 1ph sub off of it? To feed the lighting and other circuits or does it make more sense to just use the 3ph panel and make sure I don't have any 1ph circuits on the high leg?

Either one. Design choice.

You could also pull a 3 phase feeder and tap off to a single phase panel and a 3 phase disco for the oven. I that Larry mentioned this already.

 

[RumRunner]

In the initial post OP stated that he can feed these ovens from existing 3P 120/240 gear. Somewhere in the exchange OP says that the ovens are configurable.

So, instead of sweating this out, why can't you just configure the ovens for 3P and be done with it.

Yes, this an old pre WWII neighborhood and underground service entrances have rubber and fabric insulated conductors.

I rewired the Egyptian Theatre in Hollywood and it was the same thing.

 

[TNeighbarger]

Thank you all for the information and advice. I will be going down there on Monday to get a meter on it and I will let you know.

 

[LarryFine]

Actually, my thought is a 3ph panel for just the oven shunt-trip breaker(s) on one feeder, and a typical 1ph panel for the entire store on another feeder. In other words, keep them separate.

 

[480sparky]

Actually, my thought is a 3ph panel for just the oven shunt-trip breaker(s) on one feeder, and a typical 1ph panel for the entire store on another feeder. In other words, keep them separate.

Good idea.... if there's a 3-phase feed available at the meter stack.

 

[LarryFine]

The two panels can be fed from a single feeder, with joints in a J-box at the panels.

 

[TNeighbarger]

I was able to get down to the building today and open up the gear. I have a high leg of 208v and 2 legs of 120v, I have 240v across phases in any configuration. My high leg is 208v from leg to N. So I am good with pulling in the 240/120v 3ph into the suite to power the oven. I want to thank you all for your advice and wisdom.

 

[MTW]

Couple pointers about interlocking the fire system with the cooking equipment. From experience with fire Marshall's in my area.

Most fire systems today are wet systems. Since it can be conductive when it discharges, they require that ALL electrical equipment under the hood be de-enrgized when the system trips. That includes hood lighting, wall outlets, and any other wired equipment under the hood. Most systems today also require a "rate of rise heat detector" installed in the hood, and also connected in the system with the interlock.

For the air handlers, exhaust fan and air make up unit. They want the air make up system interlocked, so that it shuts down with a fire trip,
But the exhaust fan, should remain running. You want the source of fresh air (oxygen) to stop feeding the flames. Then the exhaust to keep running to keep the fire under the hood, and exhausting to the exterior of the building, where they can get to it. The exhaust duct is fully welded, spaced from combustibles and will contain any flames.

How you interlock things depends on what equipment you have, how many circuits there are, and if it's existing construction or new.

If you have several circuits, and its a new installation. One of the best ways is to provide a panel that just feeds underhood equipment, and the air make up, then provide it with a shunt trip main. One trip and everything goes down.

Provide a separate panel that feeds everything else, including the exhaust fan and the fire system control circuit. Breaker locks on these two.

With your center tapped delta service you could bring in one feeder to a trough below the panels and tap off to as many panels as the building requires. Remembering that each panel needs a main, and no more than 6 mains. One panel dedicated to the fire system equipment loads.

In old installations with existing equipment and supply circuits installed, a shutdown relay enclosure can be used to interrupt all of the required circuits. A bit more complicated, but more suited for existing kitchens.

You would be smart to speak with the fire contractor, about what the requirements are in your area. Before you get your roughing finished.

MTW

 

[TNeighbarger]

The two panels can be fed from a single feeder, with joints in a J-box at the panels.

I have yet to use the method. What kind of joints are you referring to? Like polaris or nsi style splice block? So I could take my #2 to a 16x16x6 j-box and splice of a set of #1 feeders for my 100 amp single phase circuits. Then would I have to take #2 from said j-box to a 200 amp 3 phase panel for my appliances? I have always just pulled a 100 amp single phase panel off of the 3 phase with a small jumper.

 

[TNeighbarger]

Couple pointers about interlocking the fire system with the cooking equipment. From experience with fire Marshall's in my area.

Most fire systems today are wet systems. Since it can be conductive when it discharges, they require that ALL electrical equipment under the hood be de-enrgized when the system trips. That includes hood lighting, wall outlets, and any other wired equipment under the hood. Most systems today also require a "rate of rise heat detector" installed in the hood, and also connected in the system with the interlock.

For the air handlers, exhaust fan and air make up unit. They want the air make up system interlocked, so that it shuts down with a fire trip,
But the exhaust fan, should remain running. You want the source of fresh air (oxygen) to stop feeding the flames. Then the exhaust to keep running to keep the fire under the hood, and exhausting to the exterior of the building, where they can get to it. The exhaust duct is fully welded, spaced from combustibles and will contain any flames.

How you interlock things depends on what equipment you have, how many circuits there are, and if it's existing construction or new.

If you have several circuits, and its a new installation. One of the best ways is to provide a panel that just feeds underhood equipment, and the air make up, then provide it with a shunt trip main. One trip and everything goes down.

Provide a separate panel that feeds everything else, including the exhaust fan and the fire system control circuit. Breaker locks on these two.

With your center tapped delta service you could bring in one feeder to a trough below the panels and tap off to as many panels as the building requires. Remembering that each panel needs a main, and no more than 6 mains. One panel dedicated to the fire system equipment loads.

In old installations with existing equipment and supply circuits installed, a shutdown relay enclosure can be used to interrupt all of the required circuits. A bit more complicated, but more suited for existing kitchens.

You would be smart to speak with the fire contractor, about what the requirements are in your area. Before you get your roughing finished.

MTW

The hood and fire suppression system is existing from the previous tenant. I believe sometime early 2000's, I am going to be in contact with the fire suppression company here soon. I have only used a shutdown relay enclosure before but I do like a few methods you suggested they may fit the application better and be more cost effective. Thank you

 

[LarryFine]

I have yet to use the method. What kind of joints are you referring to? Like polaris or nsi style splice block? So I could take my #2 to a 16x16x6 j-box and splice of a set of #1 feeders for my 100 amp single phase circuits. Then would I have to take #2 from said j-box to a 200 amp 3 phase panel for my appliances? I have always just pulled a 100 amp single phase panel off of the 3 phase with a small jumper.

Depends on which panel has the majority of the loads. I envision a very small 3ph panel and a large 1ph panel.