What Is an Electric Strike, Exactly?

Neighbors Ask

The short answer, then the longer one

Every latched door has a strike, the plate in the frame with a hole or pocket where the latch bolt rests. On an ordinary door that plate is a fixed piece of metal. An electric strike swaps it for a plate with a small movable keeper inside, and when the strike is energized the keeper swings out of the way so the latch can slip out. Someone pulls or pushes, the door opens, and nobody has touched the lock itself.

The part that surprises people is that the door still has its normal lock and latch. The electric strike does not replace them. It controls the other half of the connection, the frame side, which is why a door can be locked from the outside by a handle while a front desk worker releases it with a button.

So when a neighbor says "the shop has a buzzer," what is usually happening is a strike in the frame wired to a button or a reader. If you have ever been let into a small office after pressing a call button, you have probably met one without knowing its name.

What is actually inside the little box

Open up a strike and the idea is simple. There is a solenoid, which is a coil of wire that becomes a magnet when current flows through it, and that magnet moves a small blocking piece or the keeper itself. With power off, the keeper holds the latch. With power on, it lets go. Everything else in the housing is about making that motion strong, steady and repeatable thousands of times.

There are a few common shapes. Some strikes are made for a cylindrical lock with a rounded latch, some for a mortise lock with a more squared latch, and some are built to work with a rim style exit device. Each shape expects a certain latch, so the strike has to be matched to the hardware on the door rather than picked from a catalog at random.

The frame matters too. Wood frames, hollow metal frames and aluminum storefront frames all need different cutouts, and a good installer plans the opening so the frame keeps its strength. A strike that is carved into a weak frame can rattle, stick, or let the door flex under pressure.

Fail secure and fail safe, the choice that matters most

The first real decision with any electric strike is what should happen when the power goes out. A fail secure strike stays locked when power is lost, so the door stays shut against someone outside, but people inside can still leave by using the handle or lever. A fail safe strike unlocks when power is lost, so the door swings open from both sides until power returns.

Neither one is simply better. A fail secure strike suits a back door or an office where keeping the door locked during an outage is the point. A fail safe strike is sometimes chosen where a locked door could trap people. Rules about exits and fire safety vary by building and by local authority, so the right move is to ask your local building or fire official, or the person who looks after your building, before you decide.

A good locksmith will ask you about this early. If you are not sure, say so. It is a perfectly ordinary question, and the answer shapes the wiring, the power supply and even which strike body gets ordered.

• Fail secure keeps the door locked during an outage and still lets people leave by the handle.
• Fail safe lets the door open without power, which changes how the building behaves in an outage.
• Your building rules and your own building manager have the final word on which is allowed.

Where you will actually see one

Small shops use them for staff entrances and back doors, so a clerk can let in a delivery without leaving the counter. Medical and professional offices use them on the door between a waiting room and the work area. Apartment lobbies and shared entries often have a strike on the main door tied to a buzzer in each unit.

At home they are less common, though not unheard of. A gate or a garage entry on a long driveway might get a strike tied to a button inside, and some households install one on a side door for a relative who needs a simple way to let people in. The same piece of hardware works in all of these places, the difference is only the size of the job.

In our corner of the north state, picture a small shop on a main street in Redding or a little office in Anderson. The owner wants customers to come in the front, staff to use the back, and a delivery person to be let in by a button. An electric strike on the back door does exactly that without handing out another key.

What triggers it

A strike is only the muscle. Something else has to tell it when to release, and the options are broader than most people expect. A plain push button wired near the counter is the simplest. A keypad lets people with a code open the door. A card or fob reader lets a person tap a credential. A buzzer system lets someone inside release the door for a visitor they can see or hear.

Whichever control you pick, it sends a small signal to a controller or a power supply, and that device sends power to the strike for a few seconds. The release time is adjustable, so the door is not left unlocked longer than it needs to be.

This is also where choosing between a keypad or a key for a small shop comes in. A strike works with either. Think about how many people need access and how often those people change before you choose a controller.

One more thing worth deciding is whether you want a record of who came in and when. A simple button keeps no record at all, while a reader tied to a small control unit can. Most small shops do not need one, but a place with shared staff keys, supplies or cash might. Say so plainly when you describe the job, because it changes which control gets recommended and how the wiring is laid out.

How it pairs with other door hardware

A strike has to share a door with a lock or latch that behaves well. If the latch is worn or the door sags, the keeper may bind, and you will hear a buzz without the door releasing. A door that is out of square can make any frame mounted part misbehave. It is worth making sure the door closes smoothly before blaming the strike.

A closer matters as well. When a door swings shut on its own, the latch needs to meet the strike gently and fully. Read what a door closer does if your door slams or drifts. On a commercial door, exit hardware is usually part of the picture, and push bars and panic hardware work together with the strike so the way out stays simple.

The strike plate itself should be solid and well fastened, which a good strike plate article covers in more detail. An electric strike deserves the same respect: longer screws, a snug fit and a frame that is not splitting.

What to ask before you buy one

Start with the door. Is it wood, hollow metal or aluminum, and what kind of lock is already on it? Then the setup: how will people ask to come in, and who inside will let them? Then the power: is there an outlet nearby, can a low voltage line be run to the frame, and what happens in an outage?

Next, think about security without turning it into a fortress. An electric strike does not make a door stronger. A thin frame with a strike in it is still a thin frame. If the door matters for protection, ask whether the frame needs reinforcing, and whether the latch is long enough to hold.

Finally, ask about maintenance. Strikes are quiet and steady, yet they have moving parts, and dirt, moisture and power problems affect them. A sensible installer will tell you what to check each season and where the power supply lives so you know where to look if the door stops releasing.

• Door type, frame material and existing lock.
• How people will request entry and who lets them in.
• Fail secure or fail safe, and what your building rules allow.
• Where the power comes from and what happens in an outage.

Why the weather around here matters

Shasta and Siskiyou counties get hot, dry summers in the valley and snow and cold in the mountain towns. Both extremes can affect a door. Heat makes wood frames shift and metal expand, and winter cold stiffens grease and can leave a strike sluggish. Moisture from melting snow can reach outdoor mounted parts around a door in towns such as Mount Shasta or Dunsmuir.

For an exterior door, ask whether the strike is built for outdoor use or sits inside a sheltered entry. Rain and frost are not kind to uncovered electronics, and a sealed housing can be the difference between a door that works every morning and one that sticks on a frozen day.

A short walk around the building each autumn and spring pays off. Open and close the door several times, listen to the strike release, and watch whether the latch moves freely. If it hesitates, it is much easier to deal with before winter than during it.

What a professional does on the job

The work starts with measurements and a look at the existing hardware. The installer decides which strike body fits the latch, marks the frame, and cuts the opening carefully so the frame is not weakened. Wires are run so they are protected and hidden, then connected to the control and the power supply.

Before leaving, a careful installer tests the whole thing: the release from outside, the lock behavior during a power cut, the swing of the door and the way the latch meets the keeper. They also label the power supply and show you the manual way out so you are not guessing later.

Door hardware for business and business lock service are the pages that go deeper on this kind of work. If you would rather describe your door and ask a person, use the request form and tell us what you have. The phone line is coming soon.

A neighborly example

Picture a small print shop with a front counter, a work room behind it and a back door that opens onto an alley. The owner is tired of walking across the shop every time a supplier knocks. A button under the counter, wired to a fail secure strike on the back door, solves it. The supplier knocks, the owner presses the button, the door releases for a few seconds, and then it is locked again with no one having to remember to turn anything.

Now picture the same shop a year later with two new employees. Handing out copies of the back door key is a nuisance, and keys have a way of drifting away. The owner swaps the button for a keypad, gives each person a code and changes a code when someone moves on. The strike is the same piece of hardware, and the only thing that changed was the control. That is the real appeal of this setup: you can change who gets in without changing the door.

Both pictures are illustrations, not real customers, but they show how ordinary the use is. Nothing about it needs a fancy building. A willing installer, a sensible control and a door in decent shape are enough to make a small business run more smoothly.

Common mix ups and troubleshooting

A buzzing strike that does not release is often a door that is under pressure. If someone is leaning on the door, or the latch is pinned against the keeper by a misaligned frame, the keeper cannot move. Easing the load on the door is the first thing to try, and if that fixes it, the real cause is probably alignment.

A strike that clicks but never lets go may have a weak power supply, a loose wire or a latch that is out of position. A strike that stays open when it should lock may have a stuck keeper or a control that holds the release too long. These are easy to describe to an installer and hard to guess at from the outside, so write down what you hear and see.

Keep a regular key for the lock too. Power supplies fail, and a mechanical way in is the backup that keeps you from being stuck outside your own shop. If something goes wrong with a lock or latch that needs adjustment, it is a good idea to get it looked at before the strike takes the blame.

Good to know

Common questions