What is transient suppression and do I need it?

Modern societies rely heavily on electronics for every aspect of life. From health and economy to entertainment and security. The basic fact about electronics is that it uses wires or cables to transmit power and signals. Let’s put wireless to one side for now because there is not yet a viable wireless power transmission technology, which means that even wireless systems rely on connection cables at some level.

This fundamental reliance on metal conductors means that one rule of physics is unavoidable. This is that electromagnetic fields can induce electricity into an adjacent metal conductor without physical connection. Therefore, an intense burst of power near a cable can induce a damaging spike of electricity into that cable without being in contact with it. This spike is likely to damage or disable the electrical systems that the cable serves.

So what causes these spikes? Lightning is the big one given its strength and the amount of cables that are lying across the planet but lightning is not the only source of damaging spikes. Spikes are more likely to be caused by heavy machinery switching on; motors and appliances such as air conditioning can also cause damaging transient spikes.

Another name used in connection with these spikes is overvoltage. The term transient overvoltage literally means a momentary electrical spike. These spikes can overheat components in the electrical system or breakdown the insulation that contains the signals. Either way, system damage can be catastrophic.

You may have designed the best security system ever but without adequate defence, it is at risk of problems or complete failure if you don’t consider transient protection. The difficulty for the system designer is to keep the amount of protection proportional with the risk of induced overvoltage. You may consider that a domestic property in a low lightning area would need far less protection than an industrial process plant in a high risk lightning area. This assumption is probably correct but the risk assessment for how much protection is required needs to consider the potential should a system fail as well as the hazards that may cause the voltage spike.

Considering the domestic property again. The property does not have heavy machinery turning on and off but it does have air conditioning, which is quite old. It also has domestic appliances such as refrigerators etc. The wiring in the property is also old and is bunched up as it runs around the house. It’s a large house that belongs to a very wealthy person that doesn’t trust the banking system so keeps a quantity of bullion on the premises in a safe. Although the property is in a low lightning risk area, it is not unheard of that lightning strikes the ground occasionally. This person is often away on business and leaves the house empty for days at a time, relying upon the security system to alert him and the authorities if anything unusual occurs. The risk of transient overvoltage affecting this security system is quite low but the potential for loss is quite high. So the question is now, does this domestic property in a low risk area need transient suppression to protect the security system?