Electronic locking comes with a lot of jargon. There are all kinds of terms that it’s important you understand. Whether you’re a security installer embarking on new projects, or an end customer selecting a new physical security system, you need to know what you’re talking about.


This key distinction refers to the way that the lock is mounted into the door or door frame. A surface lock is fitted on top of the existing structure, protruding from the flat surface.

On the other hand, mortice locks are embedded into the existing structure. To fit a mortice lock, a hole matching the shape and size of the device must be cut into the door or door frame. A mortice lock leaves a flat surface, with the lock flush with the wall/door.


Holding force is measured in kilograms or pounds. The figure indicates the amount of weight that would be needed to break the lock by force. It is a general measure of the strength of the lock. The higher the holding force, the more difficult it would be to forcibly gain access.

All locks have holding force, whether they are electro-magnetic, strikes, solenoid bolts, or shearlocks. The difference is the mechanism that provides the holding force. For example, in an electro-magnetic lock, it is the magnetic field that generates holding force. In a solenoid bolt, it is the mechanical strength of the bolt.


Monitoring is a means of tracking the status of an electronic lock. The lock itself includes a sensor to indicate whether it is in the locked or unlocked position. Often, a multi-coloured LED signifies the status at any given time. Monitoring makes it easier to remotely observe locks and report more accurately on access and entry.


Single and double terminology applies to electro-magnetic locks. A single maglock consists of one powered magnet and its corresponding armature plate. A double maglock includes two of the same magnet in the same housing, with two matching armature plates.

Opting for a double maglock is an easy way to double the holding force at the door and improve security.

Single maglock
Double maglock


These terms apply to electric strikes. Strikes with an adjustable jaw can handle doors or frames that expand or contract with temperature or other environmental changes. The jaw adapts to the shape and position of the door. If the strike has a fixed jaw, it cannot be adjusted in this way.


Fire rating for locks refers to the ability of the lock to withstand the effects of fire. There are many different regulations for fire resistance for different types of devices. In the UK, the regulation that applies to locks and latches in BS EN 14846.

The BS EN 14846 certification comes with different levels, measured in time (usually 30, 60, or 120 minutes). This number refers to the length of time that the lock safely withstood the effects of fire under test conditions.


Side load is also sometimes known as pre-load. It refers to the force exerted on the keeper of the lock by an external force pushing on the door. There are a range of different environmental factors that contribute to side load. Misshapen or warped doors or frames, as well as degradation or loosening of the lock components can add to the friction that causes side load.

Many locks cannot operate under side load. Doors may be too difficult to open for children, elderly people, or disabled people. Some locks come with built-in protection that allows them to operate under a degree of side load, measured in kilograms or pounds.


Continuous current, also known as constant current or abbreviated to CC, is an electronic current that runs in one direction only. This type of direct current (DC) is steady, rather than pulsating.


A metal oxide varistor (MOV) is fitted inside some electronic locks. This component protects the lock from surges of voltage. Voltage spikes can occur in any electronic circuit, and can cause problems for delicate components. In locking, an MOV helps to ensure power and locking capability are consistent and reliable even in the case of voltage spikes.


Fail safe and fail secure are extremely important definitions in electronic locking. Locks of each type are better suited to different environments and contexts. Fail safe locks are locked when power is applied. If the power is cut, the device unlocks. Conversely, fail secure locks are locked by default when the power is off, and only unlock when power is applied to activate the locking mechanism.

In general, fail safe locks are used for emergency exits, in order to ensure that in the event of a power cut, anybody inside can safely get out. Fail secure locks are used to ensure that in a power cut, valuable assets remain protected by the lock.

Some locks are always the same type (for example, electro-magnetic locks are always fail safe), whereas others are adjustable between each type.

It’s vital that you have a good understanding of the key terms distinguishing electronic and electric locks. For more detailed information, take a look at our Guide to Locking.

Or, for even more key terms and simple explanations, explore our interactive Glossary.

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