Emergency Vs. Standby Systems: What Are The 5 Differences?


Choosing between an emergency or a standby system can be a difficult decision for building owners. The difference is that with an emergency system, the building owner will have to pay for installation and maintenance costs, whereas with a standby system they would not.

It is important to understand the differences between power sources so that you will know which one best suits your needs. NFPA 110, Standard for Emergency and Standby Power Systems regulates backup power systems in America.


What Is An Emergency Power System?

An emergency power system is a backup generator that kicks in automatically during an outage. They require less time to start up than standby generators and are more expensive, but they are also significantly faster at responding to outages of different severity levels.

Emergency systems have their own fuel source like gasoline or diesel which could be stored onsite, trucked in as needed, or delivered from off-site via tanker trucks.


What Is A Standby Power System?

Standby generators do not kick in until manually activated by the building owner after a major emergency has been declared. This small delay gives people inside ample warning about what’s happening outside the building so that those who need assistance can make preparations for evacuation before it becomes necessary. These types of emergency systems are less expensive, but slower to respond to.

Standby emergency power system runs off of fuel that is stored onsite. They have a battery backup and they do not need any outside connection or grid access in order to operate.

There are 2 types of standby power systems. Legally Required Standby Power Systems and Optional Standby Power Systems.


  • Legally Required Standby Power System

Required Standby Power Systems offers a brief emergency backup to ensure that your home’s lights stay on. They can be required by law or voluntarily installed without them being entirely independent like Emergency Power Systems, and they share components with the regular electricity system in order to save money.


  • Optional Standby Power Systems

Optional Standby Power Systems are optional and not required by code, yet they will supply backup power to operations that the building owner deems vital with regular outages. These systems can be activated manually or automatically, using components and wiring similar to those of a normal power system.


There are some differences between emergency and standby systems: cost, duration of a power outage before backup kicks in, power outage severity level required to activate backup power supply, response time during power outages, and battery life.


However, there are significant 5 differences that all building owners need to know:

  1. Emergency power systems kick in 10 seconds after an outage while Standby power systems take about a minute after an outage.
  2. Emergency power systems are designed to be totally independent, which means they have their own conduits and panels. These features ensure that the system has a consistent supply of electricity when needed most.
  3. Emergency power systems are critical to life safety whereas Required Standby Systems are less critical. However, it could cause hazards by hindering necessary operations during an emergency or rescue.
  4. Unlike emergency power systems, Required Standby Systems can be regarded as systems that help during escape and firefighting operations but are not life-saving. It may include heating, ventilation, communications equipment in the building automation system for lights and power management among other things such as medical equipment.
  5. Optional Standby Systems on the other hand differs from the first two in that its failure to kick in during an emergency will not impact the safety of life. It can be critical to business but is not critical to life.


Emergency power systems and standby power systems are both important, but they serve different purposes. Contact us today so we can help you determine which is best for your unique situation!

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Remote Fill Systems is the premier source for remote fill tanks and systems for generator fueling. We are committed to providing knowledgeable and experienced support to our customers from design and application through startup and commissioning. Our team has many years of experience with fuel oil as well as long experience in industrial process control and mechanical HVAC and piping systems. We have developed innovative and cost-effective products in response to customer needs, such as:


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