CQR Grade 2 Door Contact, Surface, Multi Resistored, White SC517/WH/MULTI/G2/EN

What this door contact is for

A door contact tells an alarm panel that a door or window has opened. One housing holds the switch and the other holds the magnet, and parting them changes the circuit.

This CQR contact is for wired systems, and the multi resistored design means one part can be set up for more than one type of panel. That helps an installer who would rather carry a single contact to every job.

How it works

• Normally closed: the circuit stays closed while the magnet is beside the contact housing. Move the magnet housing away and the circuit goes open.
• End of line resistors: these let a panel tell a healthy circuit from a cut or shorted cable. You select the value the panel expects rather than soldering one on.
• Double pole: the other wiring method, where alarm and tamper run as separate pairs. This contact can be fitted that way too.
• Tamper: the microswitch is there so that pulling the contact off its mounting surface can be seen by the system.

Where to use it

It goes on windows and doors inside a building. Class II covers indoor use, so a door open to the weather or an unheated outbuilding needs checking against that rating and the temperature range.

It can be used on double door configuration. Check how the panel treats that wiring before planning zones.

What the figures mean in practice

• Pull-in gap of 25 and 15: this is the working distance on the X and Y axes, in mm. A door that moves in its frame, or a wide gap between frame and leaf, can use up that allowance.
• -15°C - +40°C: this covers most heated rooms and many porches, but check any cold store or loft hatch.
• Steel frames: fixing a magnetic contact to steel often shortens its working gap, so test it in place.

Installing it

• Before fixing: fit the contact to the fixed frame and the magnet to the moving part, with the two lined up when closed.
• Choosing a resistor: read the panel's manual for its end of line type first, then match it to one of this contact's resistor types, or use your own.
• Spacers: contact spacers are an option, so check the right part with the maker before ordering.
• Testing: open and close the door with the panel in test.

Planning your system

You will also need an alarm panel with a matching input and a run of alarm cable with enough cores for the wiring method. Check the panel's resistor type before ordering.

Grade matters across the whole system. A contact at this grade can be used up to and including grade 2, so a higher graded job needs a higher graded contact.

Standards and ratings explained

• EN50131: this is the European standard for intruder alarm systems. Grade 2 generally means low to medium risk premises.
• EN50130-5 Class II: this standard covers environmental testing, and class II is for use indoors.
• IP 3X: the 3 covers solid objects over 2.5 mm, and the X means it has no rating for water.