18 AWG Shielded Cable

18 AWG is the workhorse gauge for low-current signal and detection circuits, and it accounts for the largest share of cable pulled on a typical intrusion, intercom or access control job. Heizka supplies it in 1 pair and 2 pair, foil screened with a drain wire, HDPE insulated and jacketed in gray PVC, rated 300V and packaged 305m per box. It belongs to the Heizka Security Control Cable range.

What 18 AWG Is For

Detector loops, reed contacts, glassbreak and motion sensors, keypad buses, request-to-exit devices, proximity reader data lines and intercom station wiring all draw very little current. On those circuits the limiting factor is not heating or volt drop, it is signal integrity: a milliamp-level loop running past a lighting circuit or a lift motor room can pick up enough induced noise to trigger a false alarm or corrupt a reader message. That is why the sensible specification for these circuits is a shielded 18 AWG pair rather than an unshielded heavier conductor.

The economics follow the same logic. Because these loops carry almost no current, spending on copper cross-section buys nothing, while the same money spent on a continuous screen and a properly terminated drain wire buys measurable noise immunity. Reserve the larger gauges for circuits that actually move current — 16 AWG for moderate loads and 14 AWG for long or high-current feeds.

Products in This Category

Both parts are offered in stranded bare copper and solid bare copper, carry sequential length markings on the jacket, and are ISO 9001:2008 manufactured and RoHS compliant. Listed applications are indoor remote control of security, intercom systems, sound and audio systems, door controllers, proximity sensors, keypads, access control and smoke detectors.

Installation Advantages of the Smaller Gauge

A smaller conductor is easier to install, and on a device-dense job that adds up. Overall diameter is smaller, so far more 18 AWG cables fit inside a given conduit or trunking size before fill limits apply — useful on the home-run trunk back to a panel where a dozen or more device circuits converge. Minimum bend radius is tighter, which helps at back boxes and around structural obstructions. Pull tension is lower, so long pulls through tight raceway are less likely to stretch or deform the cable.

Termination is also more forgiving. Alarm panel, expander and reader terminal blocks are commonly designed around 18 AWG to 22 AWG conductors, so 18 AWG lands directly in the screw or cage clamp without adapters or pigtails. Use the stranded version where conductors are dressed into crowded panel enclosures and re-terminated during commissioning; use solid where the termination is made once and left.

Shield Handling at the Device End

Most shielding failures on 18 AWG loops happen in the last 150mm of cable. Stripping back a long section of jacket leaves the pair unscreened exactly where it enters a noisy enclosure. Keep the jacket and screen intact as far as the terminal block allows, keep the drain wire short, and bond it to ground at the panel end only so the shield does not become a conductor in a ground loop. At the device end, insulate and terminate the drain rather than leaving it loose to short across terminals.

Frequently Asked Questions

Is 18 AWG enough for a powered device at the end of a long run?

Often not. Calculate the volt drop from the load current and total loop length before deciding. If the delivered voltage falls outside the device’s supply window, step up a gauge.

When do I need the 2 pair version?

When one device needs both a supply pair and a separate signal or tamper pair over the same route, or when two nearby devices share a route and consolidating them reduces cable count in the raceway.

Can these cables be used outdoors?

No. They are listed for indoor applications. Ask us to quote an alternative for exterior or wet locations.

What accessories pair with these runs?

Termination and management hardware is catalogued under Structured Cabling Accessories.

18 AWG shielded cable is manufactured to order for distributors, integrators and OEM customers. Confirm pair count, conductor type and quantity, check the published data in our documents library, and contact us for a quote with your project schedule.