Three-phase power and equipment wiring in New York

Most commercial kitchens, shops and larger buildings in the city have three-phase service, and much of their heavy equipment needs it. Getting it wrong shows up as motors running hot, equipment faulting, or breakers tripping at the busiest hour.

We read each machine's electrical requirements, check the service and panel have the capacity and spaces, and wire each piece with the right breaker, disconnect and conductors.

Before new equipment goes in, the service has to carry it. We check the three-phase service size, the panel's spaces and the load already on each phase, and run a load calculation for the new equipment. Where there's room, the equipment is added on new breakers; where there isn't, a new panel or a service upgrade is planned with Con Edison. The panel schedule is updated so every three-phase breaker is labeled with the machine it feeds. Spare capacity is noted for the next piece of equipment.

Combi ovens, dish machines, fryers and large ranges often need three-phase power, and each comes with its own requirements for voltage, breaker size and connection type. We wire them to the equipment plan, add disconnects where the manufacturer or the code requires them, and coordinate with the hood suppression contractor so electric cooking equipment shuts off when the system discharges. Equipment is tested under load with the kitchen staff before service starts. Cord-and-plug connections are used where equipment has to move for cleaning.

Motors are sensitive to how they're wired. The wrong rotation, a missing phase or undersized overload protection burns them out. We wire motors, compressors and pumps with starters and overloads sized to the nameplate, confirm rotation before the equipment runs, and add phase-loss protection where a dropped phase would damage expensive equipment. When a motor that used to start won't, we check for a lost phase or a failing starter before anyone replaces the motor. Nameplate data is recorded so replacement parts match.

A three-phase panel works best when the load is spread evenly. Adding single-phase equipment piecemeal over the years often loads one phase far more than the others, which overheats that phase's conductors and trips breakers while the panel looks half empty. We measure the current on each phase under normal operation, move circuits to even out the load, and document the result so the next addition goes on the right phase. A simple chart in the panel door shows which phase each machine uses.