Wireless Door Power (Securitron ICPT)By: Brian Rhodes, Published on Sep 05, 2012
Wireless electricity? Door hardware is hardly known as 'high tech', but a new product from Assa Abloy needs no wires to transfer power between the frame and door. What are the limitations of the product? Is it useful or is it a gimmick? In this note, we break down the offering and compare it to 'low tech' alternatives.
Securiton's ICPT [link no longer available], or 'Inductive Coupling Power Transfer' seemingly does the impossible: it transmits electricity through air. Given the controlled airspace typical of doors and frames, the technology is an interesting solution to the problem of 'how to power hardware hung on doors'. However, a close look reveals important constraints on proper operation:
- Low-voltage DC power transfer only, and 'air gaps' between door and frame can be a maximum of 0.25" wide.
- Power options: The voltage is field selectable for either 12 or 24VDC
- The maximum transferred current of 500MA is suitable for low-demand locks and exit devices.
- Flexible mounting: Units can be installed on top, swing, and inside edge of doors
- Wires cannot break: The ICPT is not vulnerable to snapped wires or loose connectors found in wired counterparts
- Price: MSRP for the ICPT is $159/ set
While not directly related to the ICPT product, the short video clip below illustrates the fundamental technology behind the device and how it 'wirelessly' transmits electricity through an electrical field:
Power Transfers In Use
Bringing electricity to door locks and exit devices is difficult because the door swings apart from the frame and is only attached by hinges. As a result, many 'electrified' door hardware products have internal battery packs instead of being hardwired to power supplies.
However, in some cases, especially frequently opened/closed doors, those batteries can drain quickly and need to be excessively replaced. In these situations, 'power transfers' or 'powered hinges [link no longer available]' are used to route wires through the frame, across the hinge, and to the door itself.
The Securitron ICPT has all of the benefits of a 'wired' power transfer, without exposing door loops to tampering or power wires to fatigue. Beyond better reliability and less maintenance once installed, the manufacturer also claims the product is cheaper to install because "no door core drilling is required" to route power cables inside the door.
The ICPT also has a mounting advantage over 'wired' counterparts, because it can be installed in any edge of the door, not only the 'hinge side'. While the installation gap still needs to be under 0.25" regardless, the unit can be installed in the top edge or even the latch edge of the door without issue. In some cases, locating the power transfer on the alternate edges might simplify cable runs in the frame or to the hardware on the door.
The downside to powered hinges and wire transfers is their high-maintenance cost and need for frequent replacement. The repetitive opening/closing of the door causes wires to break and connections to work loose over time, and the ICPT claims to eliminate this issue. However, for its advantages, the ICPT also presents the opportunity for new problems compared to wired alternatives:
- Tampering Issues: Slipping paper or foil in the edge gap risks killing power to dependent devices. The manufacturer suggests the ICPT is only for 'fail secure' devices so that security is not threatened, however the prospect that normal function can be interfered with so easily is a dealbreaking risk some users cannot take.
- Alignment Issues: Eventual door sag, hinge wear, or even improper closer adjustment can ultimately keep hardware from being powered. Over time, a door will move due to a variety of reasons. Normal wear and tear can prevent a door from 'returning to close' position, and even subtle misalignment between ICPT units can prevent 'wireless' power from being transfered.
- Painting Issues: The manufacturer gives no direction of how painting, common with doors and frames, affects the unit's operation. Users choosing to deploy these devices should assume that the transfer should not be painted, and masked off to prevent malfunction.
- Magnetic Interference: The ICPT uses two magnetic coils to function, and as a result can generate significant interference. This could prohibit deployment of the unit in some areas, like medical imaging or clean room environments. The manufacturer suggests the ICPT should not be used in an area where a maglock should not be used for the same reason.
- No Readers: Although not a decisive 'problem', a drawback of the ICPT is that it transmits power only. This means that the most natural powered device to hang on a door, the reader or keypad, but still be wired for data transmission. As a result, the opportunity to power access control devices is limited to 'all in one' type locksets. For most applications, the ICPT will be used to power 'dumb' electrified hardware.
Traditional 'wired' transfers can be purchased for ~$50 to ~$100. While cheaper than the ICPT, these units often require regular adjustment and periodic replacement due to broken wires.
- Typically, wired transfers are rated for 100,000 cycles [link no longer available], which can be achieved in two years if an opening averages 6 open/shut cycles per hour.
- The ICPT is not rated for a maximum number of cycles, and could surpass 100,000 cycles with no moving parts to break.
Therefore, the ~$75 to ~$100 premium for the 'wireless' ICPT unit may be offset through reduced maintenance and increased service life. However, because the ICPTs are still unproven in field use, and the the full scope of vulnerabilities and weaknesses may not be understood.