What Is a Commercial Power System?

Commercial power systems often require a lot more equipment and higher capacity loads than residential power systems. They are more complex and regulated by building codes that may include requirements for emergency lighting, evacuation and fire protection.

Larger commercial power systems use load-flow studies to help design the system and avoid overloading. Fuses can cause problems as they must be replaced after they function.

Power Distribution

The power distribution system is the electrical hub that routes and distributes electricity throughout a facility. The system includes Commercial Power System transformers, panels and feeders that manage how electricity is delivered to the individual systems and devices in a facility. Hammond Electric provides a full suite of services to design, install and maintain commercial power distribution systems. We have the experience, insight and best practices to help customers meet code requirements and design systems that are scalable for future expansions or facility changes.

A commercial power system begins at the utility pole where it transmits high voltage electricity ranging from 4.5 to 13.2 kilovolts to a transformer that adjusts the power to a lower distribution voltage. A bus then splits the distribution voltage into various directions toward the consumers of the power. Regulator banks along the lines prevent an excess or deficiency of voltage as it is distributed to the loads.

Once the power gets to the building, it goes through a meter and the device that is referred to as the main low-tension panel (PCC). This is the point in the power system where all wiring, panels and devices become the property of the building owner. From here, wires transfer the power to a main panel board or breaker box that may be located in a basement, garage or utility closet. From there, the power continues out to sub panels located throughout the facility and then to the actual devices, lights or receptacles.

Loads

In a commercial power system, loads are anything that consumes electrical energy such as lights, air conditioning equipment, refrigerators, and electric motors. The load can be single or three-phase, alternating or direct current, and has a voltage, frequency, and current rating. These ratings must be met to safely operate the load in a building’s electrical distribution system.

The voltage in a building’s electrical distribution system is controlled by a transformer. The electricity then moves through a switchgear to different power closets serving zones or floors of the building. The closets are typically connected to each other by underground cables that carry the high-voltage electricity.

Larger buildings may have a common transformer that supplies power to multiple customers sharing the same power infrastructure in a business park or industrial complex. When this is the case, harmonics produced by one customer affect equipment at other locations in the shared premises.

Having an accurate load letter is important for any facility that pays a demand charge for electricity. It helps ensure that backup equipment is sized correctly for the facility’s electrical demands. Also, it can help save money by allowing the facility to reduce its peak power usage and thus lower its demand charges. A power quality inspection can identify the causes of poor power quality and help mitigate the problems.

Switchgear

Switchgear is a group of devices that controls & switches power conductors. It is mainly used in industrial & commercial facilities. It also allows for de-energising equipment for maintenance and testing purposes. It consists of various devices like circuit breakers, fuses, HRC fuses, offload electrical isolators & moulded case circuit breakers (MCCB). Switchgear deals with voltage over 36kV so it needs special features for reliable & safe operation. It can be of outdoors or indoor type based on the voltage handled by it.

The main function of a switchgear is to protect the lines, generators and other electric-powered equipment from heavy current running through them whenever a fault occurs. This heavy current causes damage to the equipment & interrupts power supply. In order to avoid this, automatic protective devices are needed that work automatically to stop the current by closing the relay of the circuit breaker.

These devices are commonly referred to as a “fault current interrupter”. They can be air-insulated, insulated with fluid or pressurised gas. SF6 is one of the most common insulating mediums but other gases like oil can also be used. They are available in pad-mounted, vault & compact medium voltage versions depending on the area of installation. These equipments are capable of ON/OFF operation & interruption of short circuit current as well.

Generators

Power system equipment like generators ensure that businesses and organizations can continue operating during power Commercial Power System outages. These devices activate and deliver backup power to equipment when standard utility voltage declines, preventing the loss of important data and allowing for critical operations to remain running until grid power returns.

Most commercial generators use fuel to power an internal combustion engine, which produces mechanical energy that creates a flow of electric charges in wire windings. These electric charges form an alternating current that powers electrical equipment when the generator is activated.

In order to generate an AC current, the generator uses its windings to induce a rotating magnetic field in a unit known as the rotor or armature. The rotation of the armature creates a difference in electric voltage between the windings of the stator and the rotor, producing an AC output that is used to power devices when the generator is activated.

A commercial generator is typically connected to a building’s emergency electrical wiring via a transfer switch. The switch allows standard utility power and the generator to flow through the same equipment, but prevents them from using each other simultaneously. This is essential because simultaneous power use from two sources can create a backfeed, which can be dangerous to service technicians and potentially damage devices when they are restored to normal operation.