Commercial Service Upgrades & Load Calculations

There are two different situations that are important to separate.

Evaluating an Existing System

When a customer wants to add equipment or a new electrical load, OTC can evaluate the existing system and perform a load calculation to help determine whether the proposed load can fit within the available capacity.

This may be used when considering:

• New equipment

• Additional circuits

• Commercial kitchen equipment

• HVAC additions

• Machinery

• Chargers

• Tenant improvements

The purpose is to answer:

Can this load be added to what is already here?

Designing a Service Upgrade

When the project requires increasing the electrical service or substantially modifying major distribution equipment, OTC works with an electrical engineer for the required engineered calculations and design.

That may include:

• New service size

• Main service equipment

• Switchgear

• Switchboards

• Major feeder changes

• Transformer requirements

• Utility coordination

• Fault-current and protection requirements

• Engineered one-line diagrams

OTC then builds and coordinates the electrical work from the engineered design.

Capacity should be evaluated before adding substantial new electrical loads.

Common examples include:

• Restaurant conversions

• Commercial kitchens

• Manufacturing equipment

• Warehouse machinery

• Large HVAC additions

• Multiple pieces of specialty equipment

• Major tenant improvements

• Building expansions

• EV charging

Checking capacity early can prevent a customer from purchasing equipment that the building cannot support without additional electrical work.

One of the most common mistakes is seeing an unused breaker position and assuming a new load can be added.

Breaker space and electrical capacity are different.

OTC may evaluate:

• Existing connected loads

• Feeder capacity

• Main overcurrent protection

• Panel ratings

• Service capacity

• Proposed equipment load

• Voltage and phase

A panel may have empty breaker positions while the upstream electrical system is already heavily loaded.

The opposite is also possible—a full panel may still have adequate electrical capacity and simply need additional distribution.

For an existing system, OTC may review information such as:

• Existing service rating

• Panel ratings

• Existing building loads

• Major equipment

• HVAC

• Kitchen loads

• Lighting

• Proposed new equipment

• Feeder sizes

• Upstream protection

• Voltage and phase

The calculation helps determine whether the proposed load appears to fit within the existing electrical infrastructure.

If the evaluation shows that the building does not have enough available capacity, the next step is determining what level of upgrade is required.

If the existing electrical system cannot support the proposed loads, the project may require more than another panel.

Possible upgrades can include:

• Larger service equipment

• New switchgear

• New switchboard

• Larger feeders

• Additional transformers

• New distribution panels

• Underground service work

• Utility-side modifications

At that point, the project moves from a capacity check into an engineered service-upgrade project.

Major commercial service upgrades typically involve multiple parties.

OTC coordinates the construction side with:

• Electrical engineer

• Utility provider

• General contractor

• Property owner

• AHJ

• Equipment manufacturers

The engineer develops the required electrical design and calculations.

The utility confirms its requirements and available infrastructure.

OTC coordinates and installs the electrical system required to bring the new service online.

Utility involvement should begin as early as practical once a service upgrade is moving forward.

The serving utility may need to address:

• Available transformer capacity

• Service point

• Metering

• Underground routing

• Utility transformer requirements

• Service conductors

• Easements

• Energization

Utility requirements can significantly affect the electrical design and project schedule.

Waiting until the electrical equipment arrives to begin utility coordination can create unnecessary delays.

Increasing the building service does not automatically mean the utility transformer serving the property can support the additional load.

The utility evaluates its own infrastructure based on the proposed service requirements.

A project may require:

• Existing transformer verification

• Larger utility transformer

• New transformer location

• Additional underground infrastructure

These requirements are coordinated as part of the service-upgrade process.

Major electrical renovations can sometimes trigger changes to the way utility power reaches the building.

An older property may have an overhead service while the new project requires underground utility infrastructure.

That can substantially affect:

• Trenching

• Conduit

• Site work

• Service entrance equipment

• Utility coordination

• Project cost

• Schedule

These conditions need to be identified early in the planning process.

A true commercial service upgrade commonly involves replacement or modification of major service equipment.

Depending on the project, that may include:

• Service entrance switchgear

• Switchboards

• Metering equipment

• Main disconnects

• Distribution sections

• Transformers

• Main feeders

This equipment should be selected from the engineered electrical design rather than simply matching the amperage of the existing gear.

One of the biggest scheduling risks on a commercial service upgrade is equipment availability.

Large custom electrical equipment such as:

• Switchgear

• Switchboards

• Transformers

• Service entrance equipment

can have substantial manufacturing lead times.

Some large or highly customized equipment can take many months to obtain.

That makes early engineering, submittals, approvals, and equipment release extremely important.

Service upgrades usually require a period when the building's normal electrical service is unavailable.

OTC coordinates the shutdown around:

• Tenant operations

• Critical equipment

• Refrigeration

• Servers

• Building controls

• Security

• HVAC

• Production equipment

The shutdown plan should be developed before installation begins so everyone understands what will lose power and how the building will be returned to service.

Depending on the facility and project duration, temporary power may need to be considered during a service upgrade.

Temporary systems may support selected loads such as:

• Critical equipment

• Construction operations

• Refrigeration

• Business operations

Temporary power needs to be planned around the actual facility requirements and the duration of the shutdown.

A service upgrade may be triggered by a single large project or by years of incremental electrical additions.

Common triggers include:

• Manufacturing expansion

• Restaurant conversion

• Large equipment installation

• Major HVAC expansion

• Warehouse conversion

• Building addition

• Significant tenant improvement

OTC evaluates the new loads against the existing system first.

If additional capacity is required, the project can then move into engineered service-upgrade planning.

Before jumping directly to a service upgrade, OTC first looks at the actual limitation.

The problem may be:

• No breaker space

• Undersized local panel

• Inadequate feeder

• Wrong voltage

• Need for a transformer

• Poor distribution layout

rather than insufficient utility service.

A subpanel, new feeder, transformer, or distribution change may solve the problem without replacing the entire building service.

The purpose of the evaluation is to identify the limitation before designing the solution.

A commercial service-upgrade project may progress through:

1. Existing electrical-system evaluation

2. Proposed load review

3. Preliminary capacity determination

4. Electrical engineering

5. Utility coordination

6. Permitting

7. Equipment selection and procurement

8. Underground and service infrastructure

9. Switchgear and distribution installation

10. Shutdown and service cutover

11. Testing and verification

12. Final energization

OTC coordinates the electrical construction through the process while the required engineered calculations and design are handled by the project electrical engineer.