Access Control Cabling TutorialBy Brian Rhodes, Published Jan 15, 2019, 01:51pm EST
Access Control is only as reliable as its cables. While this aspect lacks the sexiness of other components, it remains a vital part of every system.
In this note, we look at the types of cables used by these systems, including 22/4, 18/6, 22/2, and where special attention should be spent when installing them.
Defining the Cabling Needed
Access control systems use three methods to carry data between components:
- Ethernet, or IP-based Systems
- Hardwired Serial-connected Systems
- Wireless Systems
Even wireless systems generally use some cabling, as the components on the door (eg: readers or door position switches) often are hardwired even if the controller is not.
Most systems specifically define which type of cabling to use, depending on which device is being installed. We examine the three most common wire types, and where they are used in access, below:
Reader Wire (6-8 Conductor Cable)
Typically used to connect Readers to Controllers, this bundle of connectors breaks down to where each conductor color handles a unique function of the reader. However, 'extra' functions (like reader beeper, or reader LEDs) may call for additional conductors, and items like power and drain wire are included apart from conductor count. The chart below details a wiring schematic for a proximity-style mullion reader:
Schematically reader wire color generally indicates the function of individual wires. For example, power is often red & black, data is typically green & white, and other features like beep, tamper, or LED color are reserved for other strands.
Here's one example of these assignments or instructions for wiring readers:
Controller Wire (Ethernet or 4 pair UTP)
This cable is commonly used between the main control panel and door controller, and may cover long distances as a result. Door devices like PIR 'Request to Exit' devices or door operator controls are wired using this type.
Unlike ethernet cabling standards that limit runs to 100 meters, these connections can span thousands of feet using the same type of cable. In most cases, while a range of cabling options will work, it is still best practice to employ whichever type the manufacturer recommends, as tech support and product warranties often depend on installing to specification:
Here's an example of an ethernet connected controller and how the RJ-45 jack is typically located with other wiring types:
Lock & DPS Wire (1 Pair)
This cable is typically used to deliver power to devices, like maglocks, strikes, or other accessory devices like illuminated RTE Push Buttons. It may also be used to wire contact sensors, door position sensors, and to cameras for I/O linked functions.
These wired connections are often just a black and red pair in a service tail from a device, like this maglock below:
Many door control devices are equipped with 'drain' wires that are included for use when a door exists in a 'noisy' RF/EMI environment. The extra wire acts as a grounded sink for ambient interference around the bundle, and helps maintain transmission between reader/controller or controller/panel.
For more, read our Drain Wire For Access Control Reader Tutorial.
Which Gauge to Use?
Wire gauge, or thickness, is a key aspect determined by cable run distance, voltage and amperage draw. The manufacturer specifies the wire's specific gauge. The most common gauges chosen in access control are 24, 22, 18, and 16 AWG sizes. In general, greater voltages and longer distances call for larger diameter wire (lower AWG number). Each component may specify different wiring, and the cable specification may change according to total distance / type of voltage used.
Unlike IP cameras where a single cable typically connects a device, an access controlled door require several different types of cables. For example, there might be a 6 conductor bundled with 4 and a 2. Here are a few examples of common combinations:
- 18/2: Lock Power
- 18/6: Reader Power/Communication
- 22/4: RTE Buttons/PIR
- 24/2: Door/Latch Position Contacts
The specific configuration of cables depends on the mix of devices used at the door. However, the number of cables normally will not exceed 4 or 5 types, and in some cases multiple devices like contrats and RTE devices can be connected on the same pair.
Factory Bundles vs DIY
These combinations may be delivered as a factory bundle or combined by the installer locally.
Many cabling suppliers offer factory bundled cables composed of the common conductors and kitted at the factory wrapped together or sealed into a single jacket. The image below is an example of a bundled product and the types of cable it contains:
Bundle Pricing: While many configurations of bundle cables are available, they typically cost more per unit length than separate cables pieced together manually. Take the example below:
- 1,000 feet of Factory Bundled Cable @ ~$1,250 or about $1.25 per foot.
Discrete Pricing: Compare that to 500 feet quantities of individually pieced cables:
- 18/4 @ $125
- 22/2 @ $50
- 22/4 @ $75
- 18/6 @ $275
Total: ~$525, or about $1.05 per foot. Using individual pricing yields a savings ~$0.20 per foot.
While straight pricing typically favors unbundled product, factory bundles reduce labor cost. A rough rule of thumb is 2 or 3 hours preparation time per 500 feet for bundling cables oneself, which saves a few hundred dollars to DIY.
Factory Bundled Pros & Cons
While more costly per unit length, factory bundled cables take no time to assemble together. Aside from improving install speed, having a single bundle of wires make hiding and protecting the cable easier than separate strands.
However, multiple variations of bundles are available, and proper specification is essential. Furthermore, not every door uses the same 'mix' of devices, and the bundle may change between openings. Additional, depending on the installed location of door components, individual cables may need to be run separately from a bundle regardless.
Running cables to door and access components is frequently more difficult than standard ethernet networks. Not only are the overall number of cables greater, the locations they run to are often farther away and in difficult to access locations. Also, the construction of doors and frames vary greatly, and running cables 10 feet at the door can be more time consuming than running hundreds of feet in cable trays or raceways.
To conceal and protect door cabling, it must often be run through door and even window frames. Take the example of a common glass 'store front' type opening, composed of swinging thin framed glass doors and 'lites'. Rather than taking the shortest route from controller to components, a longer path crossing multiple panes and frames must be taken, extending overall cable lengths and installation times.
Care must be taken when drilling into frames to not break glass, and fishing cables in tight spaces is a manual and time consuming process. Take the example storefront below, and notice the cable path must cross multiple frames to reach secure mounting locations:
Access control cabling can encounter atypical constraints. For example, access cabling is frequently run in direct contact with metal frames, and some AHJs may require more stringent insulation specifications (e.g., rigid tubing/ conduit or thicker jacket) than standard types.
Another common issue is required penetration of firewalls to connect devices. In many cases, cabling is run to avoid drilling or cuts through a rated wall, but this is unavoidable with access control installation. Drilling through a wall may require a fire-rated connector and the use of a fire-rated sealant to back-fill any holes.
Prior AHJ approval to make a penetration may be required with subsequent inspection of the final cable run. Since requirements vary by jurisdiction, checking with the AHJ is a prudent first step.
[Note: This guide was originally written in 2013 but substantially revised in 2019.]
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