Feb. 1, 2008
What are the benefits of electrically actuated cylindrical and mortise locks? The door positively latches when it is closed and shut. In fire rated and listed door situations, especially in stairwells, this is a critical requirement, since those doors provide a fire wall assembly to keep the stairwells safe and available in an emergency.

Electro-mechanical access control products are available in different configurations including electrified cylindrical locksets, mortise locks, panic/exit devices, deadbolts, strikes and trim. Each of these devices and configurations provides similar and yet unique locking applications.

One of the first things to ask when a customer inquires about electro-mechanical access control is “What type of lock mechanism is currently securing the door?”

In most instances, the customer's building is already equipped with a specific style, finish and function of mechanical locking hardware that is probably appropriate for the application. However, make sure your customer is satisfied with the current hardware, as the customer may not like it and wish to have it changed to a different style/finish. Depending upon the lock and its operating condition, it can either be electrically modified or replaced with an electrified version. Direct replacement or re-modification simplifies the installation. When in doubt, contact the lock manufacturer or the remodifier .

A primary goal of an electro-mechanical access control installation should be to make the access point blend in with the other building doors, keeping the system as transparent as possible. With a lock that matches, or closely matches existing hardware, movement of other locks to electro-mechanical access control at later dates becomes easy, since any material removed for the placement of the lock onto a door is typically contained on the interior of the door, under the skin, lock face and hinge.

Let's take a look at electrified locking hardware. An electrified lock or trim is usually a standard mechanical lockset or device that has been modified to accommodate electrification in order to control the locking mechanism. Electrified trim provides the same capability. When locked, the exterior thumb piece, knob or lever will not retract the latch mechanism until activated or a key is used.

Fail Safe or Fail Secure?

Electrical locking actuators can be either a solenoid or motor that enters the locked condition using power or when power is eliminated. Depending upon how the locking mechanism is activated, the electrified locking hardware is either Fail Safe or Fail Secure.

The Fail Safe condition requires power to lock. This means that power must be provided continuously to maintain the locked mode. The locking mechanism remains unlocked if power is lost. Hardwired systems can be designed to provide continuous power in order to keep a door locked. Battery-operated systems cannot. However, battery operated systems do not usually require continuous power to stay in either locked or unlocked mode, since they are motors, and motors can be “at rest” in either position.

The Fail Secure condition requires power to unlock. The locking mechanism remains locked if power is lost. This is why the term Fail Secure is used when power is required to unlock the locking mechanism. A Fail Secure access control system can operate using intermittent power (when unlocking only).

To install the electrical actuator, parts of the lockset need to be machined or have custom components installed. The electrical actuator can be a solenoid in hardwired systems. There are solenoids designed to be constantly powered or powered only intermittently. Most solenoids require a significant beginning amperage surge in order to operate. For this reason, most solenoid-operated locking hardware is part of a hardwired system, as batteries would be drained after few operations.

In the past, a locksmith would need to be specific when ordering an electrified lock to determine the exact function and voltage needed for a project. Most electrified locks are designed to operate on 12 or 24 volts.

Over the past year or so, several companies have begun to offer electrified locks in a dual voltage solenoid package of 12 and 24 volts. Wiring in the field can be configured by the locksmith according to the voltage needed. These dual coil solenoids have made stocking of electrified locks more cost-effective. This dual coil solenoid enables locksmiths to stock fewer locks. To further simplify stocking of product, Marray has patented a reversible solenoid that is dual coil and dual function, so a locksmith can set the solenoid for either Fail Secure (EU, Electrically Unlocked) or Fail Safe (EL, Electrically Locked).

Most standalone access control systems (battery powered) incorporate a low torque, low voltage motor. The low torque motor enables operation even if the door is slightly out of alignment. The low voltage requirement enables the motor to be battery operated, drawing a minimum amount of current. A number of battery powered locksets provide access tens of thousand of times before the AA batteries must be replaced, according to their manufacturers.

Hardwired systems offer a robust solution and no maintenance schedule is required to replace batteries. When a door is equipped with hardwired electrified locking hardware, I still recommend an annual inspection and lubrication to ensure continued optimal performance.

Hardwired systems do require running the wiring to the lock, components and power source. Hardwire installation can be relatively easy if the facility has a drop ceiling and open spaces to run the wiring. There can be a problem if the building has concrete filled jambs and no usable crawl space above the ceiling. It is extremely important to note the condition of the door jambs and ceilings before providing a quote for a hardwired access control system.

Important: Calculate the costs and benefits of the locking hardware and the running of the wiring and then compare this to the costs and benefits of the standalone unit. Then decide whether a standalone or hardwired system is more practical for the application.

What are the benefits of electrically actuated cylindrical and mortise locks? For one thing, the door positively latches when it is closed and shut. In fire rated and listed door situations, especially in stairwells, this is a critical requirement, since those doors provide a fire wall assembly to keep the stairwells safe and available for personnel to utilize in case of an emergency. Should the door not positively latch, the door could potentially blow open, causing any fire or hazardous gases or smoke to enter the safe passage to ground level.

Occasionally, Marray gets a call from a locksmith whose customer wants the “magic lock,” meaning one used in an institutional or man trap situation, where both the inside and outside handles can be electrically controlled. Should a job require a lock that is electrically controlled on both sides, a mortise lock would be the better choice over a cylindrical lock. The reason is the mortise lock would have the solenoid installed inside the chassis. This enables the mortise lock itself to control the operation of the handles.

Choosing An Access Control System?

How do you determine what type of electro-mechanical access control system is required for a specific facility? First, you want to walk your job and look at the doors that need to be electrified in order to electronically control access. Take good notes. If you have doors with cylindrical or mortise locks, determine the finish, the relative handle style (most manufacturers have similar handle styles and although they are not exact, they are sometimes very similar) and the backset. Most commercial jobs will have a 2 -3/4 inch backset, but you will find (run across an) older doors that were prepped for a 2-3/8 inch backset. To avoid any problems, measure each lock's backset. There is nothing more frustrating than getting the lock off the door, preparing the wire chase for the electrical connection and then not being able to install the lock because you have the wrong backset.

A short note here is needed about backsets. Even though 2-3/4 inch and 2-3/8 inch backsets are the most common, you will also find 5 inch and 3-3/4 inch backset locks on certain jobs. These are usually special order and you will need extra time to schedule such a job and in order to obtain any replacement parts.

Once you have determined the type of lock you need and the electrical requirements, you must also think about how you are going to get power to the locking hardware. Choices include power transfer hinges, door cords, and current transfer devices.

Power Transfer Hinges

In my opinion, the best solution for wood and hollow metal doors is to run the wiring using a power transfer hinge. Hinges are tamper-resistant; they blend in with the other butt hinges and can be used again on another door if needed. Costs for power transfer hinges have been reduced substantially in recent years.

Power transfer hinges are available fire listed and tested for use on fire rated doors and frames. Make sure that any hardware you placed on a door that is listed for 20 minutes or more of fire resistance, is listed for such use. To do otherwise will most certainly open you, your company and your insurance to potential liability, especially with the new Annual Fire Door Inspection requirements that are part of the newly revised NFPA 80 Standard. Better to do it right the first time to avoid some serious, costly situation in the future.

With that in mind, let's talk about how to determine the correct hinge needed for your job. When specifying the hinge, you will need the weight, the knuckles, the finish and the size. Most hinges are called full mortise hinges and this simply means that the hinge leaf is mortised into the door and frame, where the leaves sit flush with the surface of the door and frame and the only thing that sticks out is the barrel.

First, measure your hinge to determine sizing. Measure from the top of the leaf (not the barrel or pin) down to the bottom of the leaf. Most hinges are 4.5 inches high and 4.5 inches wide. They are not all this size, so you still must check to make sure. After you measure from the top to the bottom, open the door to 180 degrees, if possible, and measure from the right or left leaf edge, to the opposite edge. If you cannot get the door open this far, measure from the leaf edge to the center of the pin. This will give you half the distance and you can multiply by two, to get the actual full width of the hinge. Once you have these two numbers, you would call out your hinge, when ordering, with the height first and the width second. For example, you would request (would put down that you need) a 4.5 x 4.5 hinge. If the hinge were four and a half inches high, by four inches wide, you would request a hinge size of 4.5 x 4.0.


Next, examine the finish. If the finish is a brushed chrome, you might think it is a US 26D, when in fact, it is a 652, brushed chrome over steel, as 626, or US 26D, is a finish code for brushed chrome over bronze or brass. Typically, fire doors of 20 (twenty) minutes or greater cannot be equipped with brass or bronze based hinges, as they will melt too quickly. In actuality, most suppliers are aware that when you call and order a hinge with the lock finish code (626, 613, 612), what you really need is a steel based hinge with the finish to match a bronze or brass based lockset.

Also consider how the door is going to be locked when you are finished. When you install a lockset, the door is locked and controlled by the access control system. If you use electric latch release devices (strikes), you must still, in most instances, replace the entry or passage function lever set to one that has a key and is typically storeroom function. Since you are going to have to remove the lock anyway, you may as well simply drill the door and install an electrified lock. Not only does it cut down on time, but also it will cut your costs by about 30 percent , since you have half as much hardware that the customer must pay for. This makes you more competitive and speeds your job time completion.


After you decide on the type, function, finish, handle style and hinge size needed for your job, you next need to determine how you are going to drill the door for the wire that needs to come from the hinge to the lock opening. While I owned and operated a locksmith business, I would hand-drill doors with a four foot, 3/8 inch diameter alarm installer's drilling bit. However, a number of years ago, I installed two lever locks on two stairwell doors in a small city on the San Francisco Peninsula and the fire marshal would not issue a final permit for the job, since, in his opinion I had voided the fire listing on the doors by modifying them in the field. After a lot of hassle and letters back and forth to and from UL, the fire marshal and the building owner, I finally resolved the situation and the client could occupy the building.

This experience made me realize that there needed to be a better way, one in which a technician who modified a door could do so in the same exact manner each and every time. This better way would be accepted by the local AHJ, thereby making my job and the work of my colleagues much easier and code compliant. It was because of this experience that I designed and eventually had manufactured a tool that could be used the same way each and every time, to drill doors, both rated and non-rated, for wire chases on electrified lock installations. I named the tool the Dor-Cor Drilling Fixture. The tool was tested at Warnock Hersey and deemed to be within the specifications required by the door inspectors. Warnock Hersey issued a letter stating that any technician who modified a door in the field with my tool could have the door inspected and passed by a Warnock Hersey field inspector.

Times have changed. Warnock Hersey was acquired by Intertek Testing Services. Since last year, Intertek has been working with Marray , Inc., to provide a program whereby technicians can drill a fire rated door (wood and mineral core) and apply a label to the door. This program was designated “The Perfect Raceway,” a way for the locksmith to process fire rated doors in the field for electrified door hardware, while maintaining the fire listing of the opening. You can find more information on this program by going to Intertek's program specific website at www.whmark.com/raceway. They have a list of upcoming classes and the requirements for certified personnel who wish to participate in the program.

There are not too many ways you can actually field modify a fire rated hollow metal or wood door for access control locking hardware under code. Typically, if you modify the fire rated frame in the field for electric latch release (strikes), you run the risk of voiding the frame label and thereby, the entire door assembly label, since they are integrated and labeled as a whole. Should you use a door loop for power transfer, not only is it not the best aesthetic choice, but it also might not meet code and standard requirements as called out for in NFPA 80. Any hardware you place in a fire rated assembly, must itself be fire rated for the particular rating of the door. Should you have any questions or concerns on the above, please feel free to call and either speak with me, or any of my staff.

Electrified Trim

For storefront doors and non-fire rated metal pedestrian doors, there are many ways to control access. For a storefront door, you can use a magnetic lock, a shear lock, a bolt lock (not legal in some jurisdictions) or an electrified panic or electrified trim to complete the job. My choice is using electrified trim. The job requires work only on the outside of the door. The trim uses low voltage and a shorter installation time. Metal pedestrian doors can benefit from a simple electric latch panic device where there is minimal modification to the door and the job is completed quickly and efficiently.

The Marray electrically controlled single door panic device is low voltage, fits easily and efficiently onto a standard metal door, can be cut down in the field for narrow doors and is surface mounted. The device has key bypass, thereby ensuring a mechanical means of ingress in case of system failure and is Grade 1 in strength and reliability. The device comes with a one of our patented door loops, so you have everything in the box you need, except your power supply, wire and tools.

Marray offers a select number of electrified cylindrical locksets and can modify most mortise locksets to be electro mechanical. Our name brand Marray CGN series lock is a Grade 1, clutch lever cylindrical and is available in a variety of standard finishes and handle styles. This lock can also be equipped with a REX (Request to Exit Switch) so that an integrated security system with perimeter intrusion detection can be continuously monitoring the entrance points for unauthorized access. The REX is used to shunt the alarm system contact at the door, thereby telling the security system that the door was opened from the inside, rather than being forced from the outside.

Ray Zehrung started locksmithing in the late 1980's, and founded Armored Locksmith in Silicone Valley, Calif., in 1990.He became interested in electro-mechanical locking hardware and in 1995 founded Marray , Inc., a remodifier /manufacturer of most types of electrified locking hardware. Ray Zehrung is founder and president of Marray , Inc. He holds 12 patents in the security door hardware field and has been a guest speaker and instructor to industry groups for over a decade. He can be reached either via email, [email protected], or by calling at 800-500-1449