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Lightning protection for access control

Transient voltage surges, including ­lightning-related activity, cause ­companies hundreds of thousands – sometimes even millions – of rands in damage per month.

These costs will definitely increase in the years to come as our dependability on microprocessor-based electronic equipment grows.

The ANSI/IEEE-C62 definition states that transients are brief but very powerful overvoltages and currents lasting up to 100 microseconds and often reach levels of 20 kV. In extreme events, these levels may reach in excess of 100 kV.

Transients and lightning strikes are generated from sources both inside and outside a building. Internal conditions account for over 80% of the generated transients from load switching and electrical/electronic equipment operation or equipment switching on and off. These transients are of much lower voltages than external sources, however they tend to be much more frequent and may occur several hundred thousand times an hour in industrial environments.

Transients are by far the single most destructive, costly and common power related occurrence. A single high-energy transient can destroy multiple pieces of equipment and take an entire site down for extended periods of time. The loss of revenue can add up very quickly.

External sources, include lightning and power system faults/failures, account for the other 20% of the overall transient problems. These are the general source of major damage with burnt-out equipment such as computers, controllers, readers, etc, being the result.

Whether a catastrophic lightning strike or the cumulative damage built up over time, among the equipment exposed to these transients are proximity card readers controllers, Dallas ibutton reader controllers, relays for electromagnetic locks, power supplies, control panels and the like.

In severe locations it is imperative to protect the mains supply to the controllers/PC as well as the signal lines on both sides from the control panel outwards and at the reader side inwards. Surge protection equipment is inexpensive at the outset and will save both the end-user and the systems integrator a great deal of time, money and downtime.

Very often, equipment repair and replacement costs will pale in comparison to the cost of extended downtime and the associated risks of the access control systems, intruder detection equipment, CCTV systems and fire protection systems being inoperable.

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