CQR SC570/WH/G3/EN Grade 3 Surface Door Contact, Large, 6 Terminal, White

Overview

A door contact tells the alarm panel when a door or window opens. This one is a large surface-mounted pair: a contact on the frame and a magnet on the moving leaf.

It is built for wired systems up to and including Grade 3, the grade often asked for on commercial and higher-risk premises.

How it works

• Magnetic switching: while the magnet sits beside the contact, the circuit stays closed. When the door opens and the magnet moves away, the circuit opens and the panel sees the change.
• Tamper protection: the cover and wall tamper let the panel know if someone opens the case or pulls it off its mounting surface.

Where to use it

Use it on doors and windows inside the protected area, including double doors. Its environmental Class II rating covers indoor use from -15°C to +40°C.

The white HIPS housing, a high impact polystyrene, suits white frames. The same contact also comes in brown or anthracite grey.

What the figures mean in practice

• Pull-in gap: the contact closes when the magnet comes within 12 mm on the X axis or 10 mm on the Y axis. Leave less gap than that when the door is shut, so normal movement does not open the circuit.
• Grade 3: EN50131-1 sets four grades by risk. Grade 3 devices are built to resist a more determined intruder than Grade 2 equipment.

Installing it

• Alignment: as a rule, fix the contact to the frame and the magnet to the door, lined up along their length.
• Wiring: with 6 terminals, the alarm and tamper circuits run back to the panel as separate pairs.
• Testing: after fitting, open and close the door with the panel in test mode, and check the tamper circuit by lifting the cover.

Planning your system

The rest of the system decides the grade: a Grade 3 contact only gives a Grade 3 result when the alarm panel and the other devices are Grade 3 too. The British standard for intruder alarms explains the grades in plain terms.

Run the contact back to the panel in proper alarm cable, and keep joints inside tamper-protected boxes. Loose wiring and badly set gaps are common causes of false alarms.

For other door and window types, the wider range of door contacts covers flush, roller shutter and wireless models.

Standards and ratings explained

• EN50131-2-6: the part of the intruder alarm standard that covers door and window opening contacts, including how well they resist tampering.
• EN50130-5 Class II: the environmental test standard for alarm equipment. Class II covers general indoor conditions.