Engineer FAQ’s

Can I install the PA4 on a single zone?

No – the PA4 is a confirmable / confirmation HUD which requires two separate zones if the installation is to meet the requirements of PD6662:2010, and therefore EN 50131-1, DD CLC/TS 50131-7, and BS8243.


Can I install your YEND74 as a 4 wire product?

Yes – ensure no links are fitted to resistor headers A-D and 1-5. Fit a single link between pins W and X. Use all four terminals as marked.


Do your contacts work on double doors / in shared zones?

Yes – each product is different, but the installation instructions available on our website explain how this is done.





Do Knight contacts work on metal framed doors/reinforced concrete?

Installing contacts near or within metal will reduce the operating gap of the contact. The reduction is dependent on the specific material, thickness and proximity. There may be variations even between identical installations. Grade 3 contacts are especially susceptible to this problem as they are designed to trigger when this kind of interference is detected.

For flush contacts, we recommend using our AR range which is designed specifically for this purpose. Surface contacts can be brought away from the frame by using spacers SPA-LS and SPA-SS. For rollershutter contacts on steel reinforced concrete, spacers SPA-RS will help negate this effect.


How do I tell which terminals/wires are alarm/tamper connections?

There is an easy way to tell for most of our products:

4-Wire                  White=Alarm, Red=Tamper

4-Core                  Red/Yellow=Alarm, Black/Blue=Tamper

4/5 Terminal      Nickel screws=Alarm, Brass screws=Tamper/Spare

PCB contacts      Printed on PCB, refer to instructions if not

6-Core                  Same as 4-Core, but with additional Green/Blue for resistors (refer to instructions)

8-Core                  Refer to instructions


I ordered normally closed (N/C) contacts but received normally open (N/O) contacts! Why?

This is due to the interpretation of the word ‘normal’. From a strict electrical viewpoint, a switches normal position is where there is no outside force acting upon it. From a security viewpoint, the normal position is when the zone is secure – with the magnet pulling on the reed switch.

This can cause confusion. Our N/C contacts will have a closed circuit when placed near a magnet, opening once the magnet has moved far enough away – as is standard for most security systems. Our N/O contacts work oppositely – as is standard for most access control systems.

If you are unsure, please let us know so we may assist.


I want to use one of your products to switch a device off/on. Is this possible?

This depends greatly on the device in question. The majority of our reed switches are rated 1-100VDC, 1-125VAC, 500mA max current. Power hungry devices that draw in excess of this rating will irreparably damage the reed switch and fuse it in either the open or closed position. Even operating within the boundaries of the electrical rating will reduce the life of the product depending on the circuit.

It is up to you to determine the power requirements of your circuit. We recommend using a relay in your circuit if there is a power demand.


Why has my contact stopped working after X amount of days/weeks/years?

Reed switches do eventually wear out, but it will usually take hundreds of thousands of switching operations to break them. However, a fault can occur much sooner if the switch has been cracked during manufacture, assembly into our products or installation on site. Once the switch is cracked, it may operate normally for a variable period of time before finally ceasing to work completely. This is because the inert gas has leaked from the switch and the contacts within have oxidised, fusing them in place.

We test and inspect our products thoroughly, but if you are unfortunate enough to have this occur – we have a no-quibble 2 year return policy. Simply return the product to your distributor or us directly for a replacement, providing the manufacture date is within the last two years. We supply RMA numbers for this purpose on demand.


I have a poorly aligned door, which I am struggling to get a G3 contact to work on…

We produce spacers for all our G3 surface, Roller Shutter, Angle Contact and heavy Duty range. Using these you should be able to improve alignment.


I am getting unusual readings on my G3 Roller Shutter contact

Check for the presence of steel/iron in the area. If it is too close to a metal plate then you will need to fit a spacer as the metal plate will interfere with the magnetics. Maglocks can also interfere with G3 magnets


Can I install the PA4 as a standard 2 button PA?

No – the PA4 is strictly a confirmable / confirmation HUD which requires two separate zones and the two separate outputs to work.  Our standard 2 button PA range is the PA2.