Understanding Induced AC
Next to user error and defective batteries, the biggest cause of unexplained false alarms are caused by induced AC cable interference. Typically, alarm cables pick up induced AC at 1 volt per metre and substantially more where cables have been run too close to the mains. Induced AC noise causes the DC supply to alarm detectors and ancillary equipment to become unstable, causing unexplained false alarms and equipment malfunctions. Testing between DC voltage and earth with your multimeter switched to the 20VAC range will reveal how much induced AC exists from all alarm cables connected to the control panel. Fitting an ACT 1313 as standard will help eliminate this common problem.

• Prevents false alarms caused by induced AC and nearby lightning
• Clamps 12VDC against electrical spikes and connects between 12VDC supply and mains earth
• Essential for control panels and PSUs