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For many businesses, an outage isn’t just an inconvenience. Refrigerated inventory spoils, a production line stops, a server room shuts down, customers walk away. A commercial standby generator with an automatic transfer switch keeps essential operations running until the utility returns.
Know What Kind of System You Need
The National Electrical Code separates backup power into three kinds:
- Emergency systems (NEC Article 700): legally required for life safety, such as egress lighting and fire alarm in certain occupancies, with strict requirements for transfer time, separation and testing.
- Legally required standby (Article 701): required by a code or authority for things like smoke control or certain process loads.
- Optional standby (Article 702): what most businesses install to protect operations, data and inventory.
Which category applies drives the design, so it’s the first question we answer with you and, where needed, your design professional and fire marshal.
Sizing the System
We start from what has to keep running: refrigeration, HVAC, process equipment, IT, lighting, security. Then we look at measured demand from your utility data, the starting requirements of large motors, and whether load management or load shedding can keep the generator smaller. The result is a generator size, fuel type and transfer switch configuration matched to your operation.
Transfer Switches
- Automatic transfer switches (ATS) start the generator and transfer the load within seconds of an outage, then return to utility power when it’s stable.
- Service-rated ATS can serve as the building’s service disconnect, simplifying some installations.
- Multiple ATS let critical loads transfer first and others follow, or split loads by priority.
Fuel and Placement
Commercial generators run on natural gas, propane or diesel. Natural gas has unlimited runtime while gas service holds; diesel and propane depend on on-site storage. Placement has to meet the manufacturer’s clearances and local code, handle noise and exhaust, and allow service access. Permits typically cover electrical, fuel and sometimes site work.
Testing and Maintenance
A generator that isn’t exercised and maintained can fail when it’s needed. Emergency and legally required systems have testing schedules set by NFPA 110 and the fire code, including regular exercising under load. Optional standby systems should follow the manufacturer’s maintenance schedule, with routine exercising, fluid and filter service, battery checks and transfer switch testing. See commercial maintenance plans.
Generac Industrial and Commercial Generators
Progress and Heritage is a Generac Aligned Contractor. We install and service Generac commercial and industrial generators and automatic transfer switches, and other makes when they suit your facility better.
Protecting your operation from the next outage? Book a visit on our booking page and we’ll size a standby system for your facility.
Frequently Asked Questions
What size generator does my business need?
It depends on which loads must run, measured demand and motor starting needs. Load management can reduce the size needed.
How quickly does an automatic transfer switch work?
An ATS typically transfers within seconds. Emergency systems must meet specific transfer times set by code.
Do commercial generators need to be tested?
Yes. Emergency and legally required systems have code-required testing; optional standby systems should be exercised and maintained on the manufacturer’s schedule.
Natural gas or diesel?
Natural gas offers unlimited runtime while gas service holds and needs no fuel deliveries. Diesel works where there’s no gas service and is common for larger loads. We’ll compare both for your site.
Why Businesses Call Progress and Heritage
We design, install, test and maintain commercial standby power. Our licensed, insured, background-checked electricians serve businesses across Lynchburg, Roanoke, Danville, Martinsville and the surrounding counties. See our electrical installations and equipment.
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