8 min read
Fail-Safe vs. Fail-Secure Electric Strikes: Which One Your Door Needs
Fail-safe unlocks when power is lost; fail-secure stays locked. What that means for real doors, fire codes, and which electric strike to order — explained plainly.
If you are ordering an electric strike, this is one specification you cannot afford to guess. The wrong fail mode can mean a return, a failed inspection, or an opening that does not behave as the project requires during a power outage. The concept is straightforward once the terms are separated from the rest of the door-hardware jargon.
The Two-Sentence Version
“Fail” describes what happens when electrical power fails. Everything else about the choice follows from the required condition of the secure, or entry, side of the opening.
Fail-Secure Does Not Mean People Are Trapped Inside
An electric strike controls entry through the secure side of the door. When it is paired with code-compliant mechanical lock or panic hardware, egress is still mechanical: turn the inside lever or push the panic bar and the latch retracts regardless of the strike’s fail mode. The fail-safe or fail-secure choice determines what happens on the entry side when power is removed; it does not replace the required means of egress.
When Fail-Secure Is Usually the Right Choice
Fail-secure is the common default because the opening remains secured during a power outage. Exterior entries, offices, storerooms, equipment rooms, and similar controlled openings typically should not unlock simply because building power is lost.
Fire-rated door assemblies are the critical case. An electric strike on a rated opening generally must be fail-secure so the latch remains positively captured when power is removed. The strike, lock, frame, and installation must all be listed for the specific rated assembly. Always confirm the opening with the project documents and the Authority Having Jurisdiction (AHJ); a product being sold as fire-rated does not make every installation compliant.
Fail-secure strikes are also typically energized only while releasing the door. That reduces continuous load on the access-control power supply compared with a fail-safe strike that must remain powered to stay locked.
When Fail-Safe Is Used
Fail-safe hardware is selected when the secure side must become enterable after power is removed or a release signal is received. Examples can include certain non-rated interior openings and other applications specifically designed to unlock on power loss or fire-alarm activation. This is a life-safety and system-design decision, not a convenience default.
Stairwell re-entry deserves special care because the terms are often mixed together. Re-entry doors commonly use fail-safe electrified locksets or fail-safe electrified trim so occupants can leave the stair on selected floors. A fail-safe electric strike is generally not used on a fire-rated stair door because the strike must preserve positive latching. Have the hardware consultant, fire-alarm contractor, and AHJ confirm the complete opening rather than selecting a strike from the phrase “stairwell re-entry” alone.
A fail-safe strike normally requires continuous-duty DC power because it remains energized while locked. The power supply must be sized for the continuous load, including every other device on that supply. Battery backup changes how long the opening remains locked during an outage, but it does not change the strike’s fail mode.
Fail-Secure vs. Fail-Safe at a Glance
| Question | Fail-secure | Fail-safe |
|---|---|---|
| Power fails — entry side is… | Locked | Unlocked |
| Egress from inside | Mechanical and free with the proper lock or panic hardware | Mechanical and free with the proper lock or panic hardware |
| Fire-rated electric-strike openings | Generally required for positive latching | Generally not permitted |
| Typical use | Exterior, office, storage, and most controlled openings | Specific openings designed to unlock when power is removed |
| Power draw | Usually momentary during release | Continuous while locked |
| If you are unsure | Start with the project hardware schedule | Do not choose without a documented reason |
Field-Selectable and Factory-Configured HES Strikes
Some electric strikes can be changed between fail-secure and fail-safe during installation, while others must be ordered in the required mode. The model number matters. Browse the current Door Hardware inventory before matching a strike to an opening, then use our HES electric strike comparison guide for a model-by-model fit comparison.
HES 5200 series: the HES 5200C-LBM Complete Pac is field-selectable between fail-secure and fail-safe. It is intended for latchbolt lock applications and includes latchbolt monitoring.
HES 9400 and 9600 series: the HES 9400-630, HES 9400-BSP, and HES 9600-630 are surface-mounted strikes for compatible rim exit devices. These stocked models are field-selectable between fail-secure and fail-safe.
HES 9800 series: the HES 9800-630 is a low-profile surface-mounted strike for compatible Adams Rite rim exit devices and is field-selectable between fail-secure and fail-safe.
HES 1006 series: our stocked units are configured per SKU rather than converted in the field. The HES 1006CS-12/24D-630 and HES 1006CLB-12/24D-630 are fail-secure. The HES 1006CLB-F-12/24D-630-LBM is the fail-safe configuration with latchbolt monitoring; the F in the part number identifies that mode. Do not assume one 1006 configuration can be changed into the other after purchase.
A Practical Ordering Checklist
- Confirm whether the opening is fire-rated and review its approved hardware schedule.
- Decide what the entry side must do when power is removed.
- Confirm the lock or exit-device model, latch type, latch projection, frame material, and door gap.
- Verify voltage, current draw, duty rating, and available power-supply capacity.
- Check whether the exact SKU is field-selectable or factory-configured for one fail mode.
- Have the AHJ or responsible design professional approve life-safety and fire-alarm behavior for the opening.
Common Questions
Can I convert an electric strike from fail-secure to fail-safe later?
Only if the exact model is field-selectable. HES 5200, 9400, and 9800 series models discussed here can be changed in the field, while HES 1006 configurations are ordered for a specific fail mode. Check the manufacturer instructions and full part number before ordering.
Does fail-secure mean I cannot unlock the door in an emergency?
No. With code-compliant mechanical lock or panic hardware, egress from inside remains mechanical. On the entry side, the access-control system can release a fail-secure strike while power is available, and many locksets also provide keyed access.
Which fail mode do I need on a door with a panic bar?
The panic bar handles egress, while the entry-side function depends on the complete opening. A compatible surface-mounted electric strike is often used with a rim exit device, but you must match the strike to the exact exit-device model, required fail mode, door rating, latch, frame, and project hardware schedule.
What happens to an electric strike when the fire alarm activates?
That depends on the approved system design. Some fail-safe hardware is released by the fire-alarm system, while fire-rated openings with electric strikes generally require fail-secure positive latching. The fire-alarm contractor, project documents, and Authority Having Jurisdiction determine the required behavior for a specific opening.
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