What Happens to Your Access Control System During a Power Outage?
National Preparedness Month is a good time for businesses to ask a question that’s often overlooked in emergency planning:
If your building loses power, who can get in—and can everyone who needs to get out?
When the power goes out at your business, you probably think about lights, computers, phones and other equipment first.
But there’s another question businesses with electronic access control should know the answer to:
What happens to the doors?
1. Does Access Control Stop Working When the Power Goes Out?
Short answer: not necessarily.
It isn’t simply a matter of “electronic access control stops working.” The answer depends on the locking hardware, how it is powered, backup power, controller configuration, fire/life-safety requirements, and whether the opening is designed to fail safe or fail secure.
What happens during a power outage can depend on:
- The access control system
- The type of locking hardware installed
- How that hardware is powered
- Whether battery or UPS backup is available
- Controller configuration
- How the individual opening has been designed
- Applicable fire and life-safety requirements
That is why two doors in the same building may not necessarily behave the same way when power is lost.
2. Power Loss vs. Internet Loss: They’re Not the Same Thing
There is an important distinction businesses should understand:
Loss of building power and loss of internet or network communication are not the same event.
A customer hearing “cloud-based access control” could understandably assume that no internet means no access.
But cloud-based management does not necessarily mean that every access decision has to travel through the internet before the door can unlock.
For example, PDK’s Cloud Node stores site data locally, and its Red-series controller-continuity functionality is designed to allow controllers to continue making access decisions during communication disruptions.
That is different from a building-wide power outage, where the question becomes whether the access control equipment and locking hardware still have electrical power available.
3. Fail Safe vs. Fail Secure: What Happens at the Door?
One of the most misunderstood parts of electronic access control is the difference between fail-safe and fail-secure locking hardware.
PDK describes the two basic power-loss conditions this way:
- Fail safe: The locking hardware unlocks when electrical power is removed.
- Fail secure: The locking hardware remains locked when electrical power is removed.
That describes what the locking hardware does when power is lost.
It should not be confused with whether people can safely exit the building.
Entry security and egress are two different considerations.
Commercial openings must also account for applicable fire, building, accessibility and life-safety requirements. The type of locking hardware used and how an opening is configured should therefore be determined based on the specific door, its purpose, and the requirements that apply to that opening.
4. What Does Battery Backup Actually Do?
Many access control systems use battery backup so that at least some components can continue operating when normal building power is lost.
Battery backup may support components such as:
- Access control controllers
- Readers
- Locking hardware
- Power supplies
- Other powered components connected to the system
But having a battery does not automatically answer the question:
“How long will my access control system keep working?”
There is not one universal backup duration that applies to every installation.
Backup time depends on factors such as:
- Battery capacity
- The amount of equipment being powered
- The type of locking hardware
- The condition and age of the battery
- The design of the individual system
Businesses should know not only whether backup power exists, but also what equipment is actually connected to it.
5. What Happens to a PDK Access Control System During a Power Outage?
PDK is the access control platform Texas Master Locksmiths & Security Solutions, LLC works with most heavily, so it gives us a useful real-world example of how modern access control systems can respond to power interruptions.
PDK systems can be configured with battery backup so that supported access control components can continue operating temporarily when normal building power is lost.
Battery backup is not automatically included with every PDK installation. In TMLSS’s experience, whether battery backup is installed is generally based on the customer’s needs and request. To date, the PDK systems TMLSS has installed have not included battery backup.
That distinction is important because businesses should not assume that simply having a PDK—or any other access control system—means their system will continue operating during a building power outage.
If backup power is not available and normal electrical power is lost, the locking hardware will respond according to the type of hardware installed and how the opening is configured, including whether the hardware is fail safe or fail secure.
Current PDK Red 1, Red 2 and Red 4 controllers include onboard power supplies and supervised power circuits designed to monitor battery voltage, input and output power, and controller health when applicable equipment is installed.
PDK systems can also store access-control information locally rather than depending entirely on a continuous internet connection for every access decision.
That means an internet outage and a power outage can affect the system in very different ways.
How a particular PDK installation behaves during an outage depends on the way that system was designed and installed, including:
- The locking hardware used at each opening
- Whether the hardware is fail safe or fail secure
- Whether battery or other backup power was included in the installation
- Which components, if any, are connected to that backup power
- The electrical load on the system
- The individual purpose and requirements of each opening
The important takeaway for a PDK customer is not to assume that backup power exists—ask whether it was included in your particular system.
This is where real-world system design matters.
Two businesses can both use PDK access control and still experience a power outage differently because their doors, locking hardware and backup-power requirements are not identical.
6. Why Two Doors in the Same Building May Behave Differently
This can surprise business owners.
Two access-controlled doors in the same building may behave differently when power is lost.
That does not automatically mean something is wrong.
Different openings may use different locking hardware or may serve different purposes.
Factors can include:
- Whether the opening uses an electric strike, magnetic lock, electrified lock or another type of hardware
- Whether the hardware is fail safe or fail secure
- Whether the opening is an exterior entrance or an interior restricted area
- Applicable fire and life-safety requirements
- How the opening is powered
- Whether its hardware is connected to battery backup
That is why businesses should avoid assuming that because one door behaves a certain way during an outage, every access-controlled opening in the facility will behave the same way.
7. What Happens During a Long Power Outage?
Battery backup is helpful—but batteries do not provide unlimited power.
If an outage lasts long enough, available backup power may eventually be exhausted.
At that point, the locking hardware will respond according to the way the individual opening was designed.
That makes extended outages an important part of preparedness planning.
Businesses should understand:
- Approximately how long their backup power is designed to support the system
- Which components are being supported
- What happens when backup power is exhausted
- Which doors will remain secured
- Which doors may unlock
- How authorized personnel will access the facility if the outage continues
Do not wait for a lengthy outage to discover the answers.
8. What Happens When Power Comes Back On?
When normal building power is restored, access control equipment should return to normal operating conditions according to the design and configuration of the system.
But restoration of electrical service is still a good time to verify that the system and doors are operating as expected.
PDK has also noted that power restoration after an outage can sometimes be associated with electrical surges.
After a significant outage, businesses may want to verify:
- Controllers are communicating normally
- Readers are responding
- Credentials are operating correctly
- Doors are locking and unlocking as intended
- Backup-power equipment has returned to its normal state
- No power-related trouble conditions are being reported
The important point is not to simply assume that because the lights came back on, every component of the physical-security system automatically returned to normal operation.
9. Seven Questions to Ask Your Access Control Provider Before the Next Outage
You do not need to become an access control technician to prepare your business for a power outage.
But you should be able to get clear answers to these seven questions:
- Does our access control system have battery or UPS backup?
- What equipment is actually backed up?
- How long is our particular system designed to operate on backup?
- Which doors are fail safe and which are fail secure?
- Will our credentials continue working?
- What happens when backup power is exhausted?
- When were the backup batteries last tested or replaced?
Those questions are useful regardless of which access control manufacturer your business uses.
Different manufacturers and systems may behave differently, and the way an individual installation is configured matters.
The goal is not to memorize technical specifications.
The goal is to understand what your building will do before the lights go out.
Frequently Asked Questions About Access Control During a Power Outage
Does access control stop working when the power goes out?
Not necessarily. What happens depends on the access control system, locking hardware, how the system is powered, whether backup power is installed, and whether the opening is configured to fail safe or fail secure.
Will my keycard or credential still work during a power outage?
It may, if the controller, reader, locking hardware, and other required components still have power. If normal power is lost and there is no backup power, the opening will respond according to the installed hardware and system configuration.
Does every access control system have battery backup?
No. Battery backup is not automatically included with every access control installation. It may be available as part of the system design, but businesses should verify whether backup power was actually included in their specific installation.
Does a PDK access control system automatically include battery backup?
No. PDK systems can be configured with battery backup, but backup power is not automatically included with every installation. Texas Master Locksmiths & Security Solutions has not yet installed a PDK system with battery backup because that option is generally based on the customer’s needs and request.
What is the difference between fail safe and fail secure?
Fail-safe locking hardware unlocks when electrical power is removed. Fail-secure locking hardware remains locked when electrical power is removed. These terms describe what the locking hardware does during power loss and should not be confused with whether occupants can safely exit the building.
Is losing internet the same as losing power to an access control system?
No. Internet or network loss and electrical power loss are different events. Some access control systems, including PDK systems, can store access information locally and continue making access decisions during certain communication disruptions, while a power outage affects the electrical power available to system components and locking hardware.
How long will access control battery backup last?
There is no universal answer. Backup time depends on battery capacity, the equipment being powered, the type of locking hardware, battery condition, system load, and how the installation was designed.
What should a business check after power is restored?
After a significant outage, businesses should verify that controllers and readers are communicating normally, credentials are working, doors are locking and unlocking as intended, backup-power equipment has returned to its normal state, and no power-related trouble conditions are present.
Don’t Wait for the Power to Go Out to Learn How Your Doors Work
Access control is one part of your building’s larger physical-security and emergency-preparedness plan.
National Preparedness Month is a good reminder to look at more than emergency supplies and weather procedures.
If your business relies on electronic access control, you should understand what happens to that system during a power outage, what equipment has backup power, how individual doors are configured, and what happens if an outage lasts longer than expected.
Texas Master Locksmiths & Security Solutions works heavily with PDK access control systems while also helping businesses understand the physical-security principles that apply regardless of manufacturer.
If you’re unsure how your access-controlled doors will behave during a power outage, that’s a good question to answer before the next outage occurs.
Don’t wait for the lights to go out to learn how your doors work.
Prepared. Aware. Secure.
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