All About Interconnected Locks

Combining the added security of a deadbolt and the easy egress of a lever handle or knob, interconnected locks have a broad range of uses for commercial and residential buildings. An interconnected lock is basically a knob or lever set and a deadbolt connected together. Interconnected locks are available for several door preparation types and in many styles. Many people prefer the interconnected mechanism for their residence because it is secure and easy to use. Municipalities often require interconnected locks for apartment buildings, assisted living centers, and hotels or motels because of the single-action egress the interconnect provides. In this article, we discuss the various types of interconnected locks and their uses.

How Interconnected Locks Work

An interconnected lock is a knob or lever handle and a deadbolt linked together for simultaneous action. There are two types of interconnected lock mechanisms: standard tubular locks with interconnect and mortise locks.

Standard tubular locks are what most people will find on doors in residential settings. The interconnect device ties the lever together with the deadbolt. Both the lever and the deadbolt can be locked. With one single turn of the lever from the inside, the lever handle and deadbolt are both unlocked. This is why the interconnected lock is often required for apartment buildings. One quick turn of the lever unlocks both locks for fast egress. From the outside, the lever and deadbolt must both be unlocked with a key.

Styles of Interconnected Locks

Standard tubular locks with interconnect devices are available for both residential and commercial applications. They are offered in many style options including handlesets and sideplate locks. Examples of tubular locks available with interconnect devices include products from Emtek, Schlage, Weslock, Weslock Unigard, and EZSet.

Door Preparation for Interconnected Locks

The door preparation is the size and location of the holes drilled in the door for lock installation. There are a few common door preparations, and some interconnected locks are designed to work with each. If you are buying an interconnected lock to fit a door that has already been drilled, it is critical to check the size and spacing of the holes to make sure the lock will fit your door.

All tubular interconnected locks require two 2-1/8 inch face bore holes and two 1 inch cross bore holes. The center-to-center measurement needs to be 5-1/2 inches, 4 inches, or 2-7/8 inches. The most common door prep for residential doors is 5-1/2 inch center-to-center. The 2-7/8 inch center-to-center measurement is a less common residential and light commercial application. 4 inch center-to-center door prep is a commercial preparation frequently used in apartment buildings and assisted living centers.

Door Preparation for Interconnected Tubular Locksets

5-1/2 Inch Door Prep	4 Inch Door Prep	2-7/8 Inch Door Prep

Interconnected Mortise Locks

Mortise locks function in the same way as interconnected tubular locks. Mortise locks have a large lock box mechanism mortised into the edge of the door. This lock type is easy to recognize by its tall one-piece faceplate on the door edge, normally about 8 inches by 1-1/8 inches. A keyed mortise lock is much like a regular lever or knob and a deadbolt combined into one unit. Mortise locks are strong, long-lasting locks and are typically more expensive than tubular locks.

The images below show the door preparation required for a mortise lock and an example of a mortise-style lock. These locks are available in many styles.

Mortise Lock Door Prep	Mortise Lock Mechanism	Handleset with Mortise Lock

Choosing the Right Interconnected Lock

There are many style options and applications for interconnected locks. If you need help figuring out which interconnected lock to use, please call 877-852-9449 Monday through Friday, 9 AM to 5 PM Mountain Time, or contact us by email at info@directdoorhardware.com.