How to Design a Reliable Commercial Power System

Commercial Power System

How to Design a Reliable Commercial Power System

Commercial buildings require a power system designed to accommodate the type of business conducted. The power system must also be able to handle the sensitivity levels of the electronic equipment that is installed.

Electrical designs for larger commercial systems often include studies for load flow, short circuit fault levels and voltage drop. These studies are intended to assure proper equipment and conductor sizing and to coordinate protective devices when a fault occurs.


As electricity leaves the meter, it travels through a circuit breaker or panel board, sometimes called a main disconnect or main service breaker. This device is also often referred to as the main power breaker and is used to shut off power to the entire facility. From here, the electricity will continue down a primary bus or feeder that is connected to sub panels located throughout the building, serving individual devices like lights and receptacles.

This is where power quality problems may begin to show up, with noticeable effects on the operation of equipment, such as flickering lights or data loss. A professional power quality survey will provide the information necessary to identify the problem areas and determine targeted mitigation techniques.

The most important safety feature of any power system is its grounding. Without a properly functioning grounding system, anyone touching a conductor (power line) can receive a shock. The reason for this is that a complete path of current from the voltage source to the victim can be made through two points: one on the body, and the other on the ground. With a grounded power system, however, the person’s feet make contact with the ground, providing a path of protection. This is why ungrounded systems are dangerous and should never be touched without proper footwear.


A commercial power system needs to be efficient enough to meet your business’s energy requirements. Using an energy efficient system can reduce your electricity bill and carbon emissions while keeping your business running.

Conductors transfer power from the electric supply to your building’s panels and devices. They must be rated to deliver the voltage, current and frequency that your equipment requires for it to run. These ratings are established by a variety of standards. For example, transformers must be rated for copper losses and iron loss to ensure proper performance and long life. The same is true for switches, generators and other devices.

In addition, your power system should be able to supply instantaneous emergency power. A reputable uninterruptible power supply, also known as an UPS, uses batteries or flywheel technologies to create and store energy during outages. It’s important to consider Commercial Power System the type of business you conduct in your facility and the length of time you might need backup during a power outage.

The UPS’s main control point, often called the primary disconnect or main circuit breaker, shuts off the power supply to the entire facility when necessary. From there, it sends power to sub panels located throughout the building and from those panels to the individual devices, lights and receptacles. Voltage optimisation is another way to improve your power system’s efficiency. This technology regulates the incoming voltage and lowers it to suit the device on the other end, which is less expensive than running your equipment at higher volts.


Reliability reflects the probability that an electrical system will perform its intended function without failure over a specified time, under specific conditions. It is usually expressed as an availability percentage (e.g. 99%). Power quality issues that impact equipment reliability are of major concern to commercial and industrial customers because of the potential loss of productivity, products, or data. In the past, electro-mechanical equipment was often able to tolerate minor power quality problems. As loads have shifted to more electronic equipment, power quality concerns have increased.

A commercial power system’s reliability is a function Commercial Power System of the design, operating and environmental conditions, and maintenance practices. Ideally, all of these features would work together to provide clean and steady power 24/7.

Power system reliability has received negative media attention recently, but overall electricity reliability is fairly high in the United States. The most reliable transmission and distribution systems are designed with bigger conductors and better insulation levels, and built-in redundancy where possible.

Some utilities are addressing reliability concerns by using performance-based rates, which incorporate reliability targets and reward/penalty systems into the utility rate structure. Other utilities are deploying reliability-centered maintenance (RCM) techniques, which use information-based analysis tools to enable field technicians to focus their efforts on repairing components most likely to fail, minimizing outages and repair costs. In addition, new telemetry technologies allow circuit breakers and transformers to telemeter thermal data directly into RCM databases, eliminating the need for annual infrared inspections.


The commercial power system features a wide range of electrical equipment that serves multiple purposes and must operate under different conditions. Facilities professionals should use a thorough survey to identify which equipment and systems need more comprehensive maintenance. To do this, work at the operation level and analyze each piece of equipment to determine unique circumstances, such as whether a machine operates on a single or three-phase power supply, its sensitivity to power quality issues, and its potential for overheating and other faults.

Generally, commercial facilities are more complicated than residences and require a more sophisticated wiring set-up. They also may utilize three-phase power to energize heavier equipment and require higher-capacity protective devices to protect people and property. Using the results of a survey, a facility can create a more focused preventive maintenance plan.

Review the circuits that carry critical life-support equipment and ensure they are rated to support the load. Also, inspect room circuits for overheating and check that receptacles are rated to the number of outlets connected. Review receptacles and lighting sources for signs of usage-based deterioration and replace them as needed. Lastly, review HVAC time-of-day schedules, temperature setups and settings, programmable controls, occupant and tenant use requirements, and other strategies and procedures that stage or turn equipment on and off. Incorporate these reviews into a computerized maintenance management software (CMMS) system.

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