Commercial Subpanels & Dedicated Circuits

A dedicated circuit serves a specific piece of equipment or load instead of being shared with general lighting or receptacles.

Dedicated circuits are commonly used for:

• Commercial kitchen equipment

• Refrigeration

• Microwaves

• Coffee equipment

• Copiers and printers

• HVAC equipment

• Motors

• Pumps

• Machinery

• Servers and technology equipment

• EV chargers

• Specialty appliances

The circuit is sized around the actual electrical requirements of the equipment being served.

Connecting a significant new load to an existing general-purpose circuit can create problems such as:

• Breaker trips

• Circuit overloads

• Voltage problems

• Unreliable equipment operation

• Disruption to other devices sharing the circuit

OTC verifies the load before deciding whether an existing circuit can be used or a new dedicated circuit should be installed.

The closest receptacle or junction box is not necessarily the correct power source.

A subpanel can be a practical solution when the building has available electrical capacity but needs additional breaker space or electrical distribution closer to the area being served.

Common situations include:

• Main panel is physically full

• New office area is far from existing distribution

• Warehouse equipment is concentrated in one area

• Multiple new circuits are being added

• Restaurant equipment needs additional distribution

• Facility is being expanded

• Future equipment additions are expected

Instead of running numerous long branch circuits back to the original electrical room, a properly located subpanel can create a cleaner distribution point closer to the loads.

Running out of breaker positions and running out of electrical capacity are not the same thing.

If the existing electrical service and feeder have enough capacity, a new subpanel may solve the problem without increasing the building service.

OTC evaluates:

• Existing panel capacity

• Available breaker space

• Feeder capacity

• Upstream protection

• Existing building load

• Proposed new loads

before deciding whether additional distribution or a larger service is actually necessary.

A subpanel requires a properly sized feeder from an upstream electrical source.

The feeder design may include:

• Breaker or overcurrent protection

• Conductors

• Conduit

• Grounding

• Neutral

• Panel rating

• Voltage and phase

The size of the feeder depends on the loads the subpanel is intended to serve.

Where the subpanel is installed can have a major effect on the project.

A good location can reduce:

• Branch-circuit length

• Conduit runs

• Voltage-drop concerns

• Future installation costs

The location also needs to consider:

• Accessibility

• Working clearances

• Building layout

• Equipment locations

• Future expansion

• Physical protection

OTC looks at both the electrical design and how the building actually operates before selecting the distribution location.

Commercial buildings can create significant distances between the existing panel and the new load.

Longer runs may require consideration of:

• Conductor size

• Voltage drop

• Conduit routing

• Circuit load

• Equipment starting characteristics

On longer circuits, OTC pays additional attention to voltage drop and overall conductor sizing so the equipment receives usable voltage at the point of connection.

Commercial kitchens often require multiple dedicated circuits for equipment such as:

• Refrigerators

• Freezers

• Ovens

• Fryers

• Dishwashers

• Ice machines

• Coffee equipment

• Warmers

When several new circuits are required in the same area, adding a local subpanel may provide a cleaner solution than running every circuit back across the building.

Office tenant improvements may require dedicated circuits for:

• Microwaves

• Refrigerators

• Coffee equipment

• Copiers

• Printers

• Server equipment

• Conference-room systems

• Specialty office equipment

Breakrooms in particular can place more demand on the electrical system than expected when multiple appliances operate at the same time.

Warehouse and light-industrial facilities may use subpanels to distribute power closer to:

• Machinery

• Production areas

• Workstations

• Chargers

• Maintenance areas

• Office build-outs

• Mechanical equipment

Local distribution can make future equipment additions easier while reducing the need to repeatedly run circuits from a distant electrical room.

New or relocated HVAC and mechanical equipment may require:

• Dedicated circuits

• Feeders

• Disconnects

• New breakers

• Additional distribution

OTC coordinates the electrical requirements with the approved equipment information so the circuit and protection match the equipment being installed.

Commercial EV charging can create substantial electrical demand.

Before installing charging circuits, OTC evaluates:

• Charger requirements

• Existing panel capacity

• Available service capacity

• Feeder capacity

• Charger quantity

• Installation distance

Depending on the project, the solution may include dedicated circuits, a new subpanel, or larger distribution upgrades.

Subpanels and dedicated circuits need to match the electrical system and the equipment they serve.

Commercial systems may involve:

• 120V

• 208V

• 240V

• 277V

• 480V

• Single-phase

• Three-phase

OTC verifies the required voltage and phase before planning the new distribution.

If the building does not have the required voltage available, a transformer or larger distribution change may be necessary.

Sometimes the building has adequate electrical capacity but not the voltage required for the new area or equipment.

In those situations, the solution may include:

Existing Distribution → Transformer → New Subpanel → Branch Circuits

A common commercial example is using 480V distribution to supply a transformer that provides 208Y/120V power for local equipment, receptacles, or office areas.

If a new subpanel is being installed, it makes sense to consider reasonable future needs.

That may include:

• Additional equipment

• Future tenant changes

• More workstations

• Additional appliances

• Expansion of production

• More chargers

Providing some practical room for future circuits can reduce the need to replace or expand the new panel shortly after installation.

Before adding a new feeder or dedicated circuit, OTC also looks at the condition of the existing electrical equipment.

If the upstream panel has:

• Bus damage

• Significant overheating

• Loose connections

• Obsolete equipment

• Other serious deficiencies

it may not make sense to add new loads to it without addressing the existing condition first.

Sometimes the evaluation shows that the existing system simply does not have enough capacity for the proposed work.

In that case, the project may require:

• Larger feeder

• Panel replacement

• Transformer

• Switchgear modifications

• Service upgrade

OTC identifies the limitation before installing new distribution so the customer does not spend money on a solution that only moves the problem somewhere else.

A typical project may include:

• Existing system evaluation

• Load review

• Circuit or feeder sizing

• Panel capacity verification

• Conduit installation

• New feeder

• Subpanel installation

• New breakers

• Dedicated circuits

• Disconnects

• Equipment connections

• Testing

• Panel labeling

The scope depends on whether the project needs one circuit or an entirely new local distribution point.