Running Wires to Electrified Door Hardware
There are three common methods for transferring low-voltage power from a wall to a door and connect it to the electric security door hardware: (1) power transfers, (2) external flex conduit and (3) electric hinges.
A power transfer - commonly referred to as an EPT or PT - provides flex conduit hidden within a pocket that is concealed within the hinge side of the door. Power transfers protect the wiring and allow larger gauge wires for powering door hardware that draws more current and higher amperage. Power transfers should be considered in the initial design and ordered as part of the door and frame, as they are not easily retrofitted into the door.  
External flex conduit (also known as door loop)  is probably the most widely used option for transferring power, as it is the least expensive and easiest to install. Exposed flex conduit can easily be vandalized, however; and on high-use doors, the external conduit loop can be a catch hazard for people as they exit. Concealed flex conduit kits have appeared on the market, which, depending on wall construction, may be a great retrofit option.
Electric hinges provide a concealed and vandal-resistant method for getting wires from the door frame to a door equipped with electric locks and exit devices. Electric hinges can often be retrofitted into a door application, depending on the wall construction, the pattern of the holes and the size of the hinges. Electric hinges are typically available with 4 wires up to 12 wires. Electric hinges typically use smaller diameter wire, which can limit their ability to power products with higher ampere draws. To overcome this issue, some installers will "double up" or use multiple electric hinge wires for each side of the direct current. Because the wires are routed through a pivoting hinge, they can flex and eventually break. Most suppliers provide extra wires, allowing continued use of the electric hinge by simply switching wires when necessary. Electric hinges are designed for doors that require concealed low-voltage current transfer, concealed electric monitoring or concealed low-voltage current transfer with monitoring.
Electric continuous hinges are a low cost alternative to custom hinges. They have a significant advantage over shorter hinges, as they're cut to the size of the door to maintain the frame of the door in an exact position to minimize wear and tear. The continuous hinge will automatically dissipate any pressure when continually opening and closing the door. Other advantages include less noise, easy installation and increased life span.
Did You Know?
Some electric hinges are supplied with small gauge wires, however powering an electric latch retraction device on the door with 24 volts at 2 amperes can generate heat that can damage small gauge wires. Some installers will consider combining smaller wires, using a total of 4 or 6 small gauge wires, instead of just the standard 2 wires.

Although this practice is common in our industry, increasing the wire gauge by combing several smaller gauge wires, can lead to short circuits and still generates unwelcome heat eventually resulting in failure. The Detex EWH8 Electric Wire Hinge is supplied with two 18-gauge wires for power and six 22-gauge signaling wires.
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