Fail-Safe vs Fail-Secure Locks: Which One Does Your Door Need?
Short answer: a fail-safe lock opens when power is lost, and a fail-secure lock stays locked. Choose fail-safe for any door people must be able to leave through in a power cut or fire, such as office entrances, glass doors and escape routes. Choose fail-secure for doors where keeping things in matters more than walking out freely, such as a house main gate, a store room or a server room, and make sure those doors can always be opened from the inside by hand.
What does fail-safe mean on an electric lock?
Fail-safe means "safe for people". The lock needs power to stay locked. Cut the power, whether by a reader, an exit button, a break-glass or a mains failure, and the door releases. An EM lock is always fail-safe because a magnet cannot hold without current. The EM-602 listing states fail-safe operation, and the EMCON-62 concealed EM lock is listed as "fail safe, lock when energized".
What does fail-secure mean?
Fail-secure means "secure for property". The lock needs power only to open. With no power, the bolt or latch stays where it is and the door stays locked from the outside. Most motorised and electronic rim locks behave this way. The RML-8K rim lock, for example, has a self-locking latch that locks again as the gate closes, and a 32 mm brass key cylinder for opening from outside during a power cut.
A fail-secure door must still open from the inside with a handle or knob, without power and without a key. That is what keeps it safe for the people behind it.
How does each type behave in a power cut?
| Situation | Fail-safe (EM lock, fail-safe drop bolt) | Fail-secure (rim lock, fail-secure strike) |
|---|---|---|
| Mains power fails | Door unlocks | Door stays locked |
| Fire alarm or break-glass pressed | Door unlocks | No change unless wired to release |
| Leaving from inside | Exit button, or free in a power cut | Inside handle or knob |
| Getting in from outside with no power | Door is open | Key override, if fitted |
| Power used day to day | All the time while locked | Only for a moment while opening |
| Needs battery backup to stay secure | Yes | No |
Which locks on our store are fail-safe, fail-secure or switchable?
- EM locks: always fail-safe. Simple, no moving parts, and the default for most office doors.
- Drop bolts: the DBWD-05 listing states it is adjustable fail-safe (power to lock), which suits public places. For other drop bolt models the listing does not state the mode, so ask us before you buy if it matters.
- Electric strike: the STFC-02 can be set as fail-safe or fail-secure. Set it before fitting. It works with an existing mortise lock, so the handle on the inside always opens the door.
- Electronic rim locks: behave fail-secure. The latch stays locked without power and a key opens it by hand.
Which one does your door need?
- Office main entrance or glass door: fail-safe. People inside must be able to walk out if power fails. An EM lock with a U or GG bracket, or a fail-safe drop bolt, is the usual choice. Our glass door lock guide covers which suits your glass.
- Fire exit or any door on an escape route: fail-safe, with a break-glass that cuts power to the lock directly. Follow your local fire safety rules and building approvals.
- House main gate or outer metal door: fail-secure. You do not want the gate swinging open during a power cut at night. An electronic rim lock with key backup suits this; see our electronic rim lock price guide.
- Store room, cash room, server room or record room: fail-secure, as long as nobody can be locked in. A strike set to fail-secure keeps the existing handle for leaving.
- Cabin doors inside an office: either works. Fail-safe is simpler; fail-secure saves power.
What about power cuts in India?
Frequent cuts are the real-world problem with fail-safe locks. If the door must stay locked through a cut, do not swap to a fail-secure lock on an escape route. Keep the fail-safe lock and add a battery backup power supply so it stays powered, while the break-glass and exit button still release it. Our access control power supply guide explains how to size one. For wiring, fail-safe locks go on the reader's COM and NC terminals and fail-secure locks on COM and NO; the steps are in how to wire an EM lock.
Fail-safe and fail-secure locks with prices
| Lock | Type | Behaviour (from the listing) | Price |
|---|---|---|---|
| EM-602 EM lock 600 lbs | EM lock | Fail-safe, 280 kg, 12/24 V DC | ₹1,499 |
| EMCON-62 concealed EM lock | EM lock | Fail-safe, lock when energised | ₹2,450 |
| DBWD-05 drop bolt with feedback and timer | Drop bolt | Adjustable fail-safe (power to lock) | ₹1,990 |
| DBWD-02 wooden door drop bolt | Drop bolt | Mode not stated; ask before ordering | ₹1,950 |
| DBFG-05 frameless glass door lock | Drop bolt | Mode not stated; for 8 to 15 mm glass | ₹2,899 |
| STFC-02 electric strike | Strike | Set as fail-safe or fail-secure | ₹2,490 |
| RML-8K electronic rim lock (lock only) | Rim lock | Self-locking latch, key opens in a power cut | ₹3,799 |
| Secureye SC-S-200EL rim lock | Rim lock | Brass latch and deadbolt, keys for power outages | ₹2,450 |
| Combo-CN33 strike lock remote kit | Strike kit | Strike, receiver, 2 remotes, power supply | ₹3,999 |
Compare more options in EM locks, drop bolt and electric strike locks and electronic rim locks, or use the access control kit builder to match a lock to your door.
FAQ
Is an EM lock fail-safe or fail-secure?
Always fail-safe. It holds only while powered, so the door releases the moment power is cut.
Which is safer for a fire exit?
Fail-safe, with a break-glass wired in the lock's power line. It lets people out even if the reader or controller fails.
Can a fail-secure lock trap someone inside?
Not if it is fitted properly. A fail-secure door must have a handle or knob on the inside that opens it mechanically, with no power or key needed.
Can one lock do both?
Some can. The STFC-02 electric strike can be set as fail-safe or fail-secure, and the DBWD-05 drop bolt is listed as adjustable fail-safe.
How do I keep a fail-safe door locked during a power cut?
Add a battery backup power supply. The lock stays powered through the cut, and the exit button and break-glass still release it.
Does a fail-secure lock use less electricity?
Yes. It draws power only for a moment while opening, while a fail-safe lock draws current the whole time the door is locked.
Prices are NavKar Systems website prices on 27 October 2026, inclusive of GST, and may change.
