CQR Large Surface Alarm Door Contact, 6 Terminal, Grade 2, Brown SC570/BR/G2/EN

Overview

This is a larger contact for fixing on the surface of a door or frame. It comes as a contact and a separate magnet in matching brown housings.

It is a straightforward grade 2 part.

How it works

A magnet on the moving part keeps a switch in the contact in its normal state. When the magnet moves away, the switch changes state and the alarm panel sees it.

Where to use it

It suits domestic and commercial alarm circuits and double-door applications. Environmental class II is an indoor class, so keep it out of the weather.

What the figures mean in practice

• Pull-in gap: this is the distance at which the magnet makes the contact operate. Measure the real gap and allow for doors dropping over time, as a widening magnet gap is a common cause of false alarms.
• Switching current: 500mA @ 12Vdc is the switch's rated load.
• Rhodium contact: rhodium is a hard metal plating used on switch contacts.

Installing it

• Fixing: the contact measures 85 x 25 x 21mm and the magnet 85 x 18 x 21mm, so check there is flat room for both.
• Wiring: use the 6 terminals as the panel's wiring guide requires.

Planning your system

The job also needs an alarm panel with a matching zone input, plus cable to the contact. Check the system grade first, as this is a grade 2 part.

Browse other door contact styles if the gap or door type calls for something different.

Standards and ratings explained

• EN50131-2-6: this is the part of the European intruder alarm standard that covers opening contacts. Read more in the guide to the intruder alarm standard and its grades.
• Grade 2: grades run from 1 to 4, and grade 2 is generally for low to medium risk.