If water had got into the wiring of an alarm or access control system how would it show itself and how should we go about troubleshooting for it?

A: Water damage to wiring is much more common that you’d think. As water penetrates the sheath what you’re going to get first is noise on the wire indicating high frequency leakage between the conductors. Water conducts electricity a whole lot better than PVC, remember.

You’ll also get greater impedance (this may not be measurable, even on an oscilloscope) and the level of isolation will fall. As the copper corrodes you’ll get increasing resistance and a lot more noise. In the end you’ll get false alarms as electrical signal drops below the circuits designed thresholds.

We’d recommend using a gel-filled cable for wet runs. If you need to re-install the job as a result of water damage, invest in this cable type – it won’t let you down.