Adding second bell-box to house alarm

House alarm systems normally have a live bell-box on the front of the property amd a fake-box upon the rear. Should you decide to fit a second live bell-box to the rear you need to be aware of the following;

If you wire the second bell-box in parallel with the first bell-box at the alarm control pannel the alarm will appear to function correctly under test conditions and you will not know anything different.

Firstly, the bell-box tamper circuits will not activate the main alarm control pannel unless both boxes are tamperd with. To address this the bell-box tamper circuits must be wired in series i.e. supply tamper from the control pannel feeds the tamper input within the first box, the tamper output from the first box feeds the tamper input of the second box and lastly, the output from the second box is the return tamper to the control pannel.

Secondly, most alarm control pannels are not able to directly supply both bell-boxes due to current loadings, so this means that the first box is wired as standard, thus being Self-Activating-bell (SAB) and the second box should be wired Self-Contained-Bell (SCB). What this means in english; The first bell-box & strobe are powered by the main control pannel and the second bell-box and strobe are powered by the bell-boxes own internal nicad battery i.e. SCB, thus meaning that only trigger current is added to the loadings of the main alarm control pannel. SAB and SCB on most alarms can be selected by changing a jumper within the bell-boxes electronic circuitry, it maybe selected by programing on some alarm systems. PS just to mention, the volume of the bell within the second bell-box will be slightly lower upon activation, this is quite normal due to running on smaller battery etc.

Hope this helps, regards, Snowy