Written by Mark Lloyd, Senior Product Manager- Power Supplies & Surge Protection

If you were to ask any electrician or plant maintenance engineer what the main reasons are for electrical equipment failure, some of the answers would be insulation degradation, poor grounding, bad connections but I would put money on voltage spikes as being one of the top answers…..

Voltage spikes can be harmful to electrical and electronic devices and increasing the voltage above a devices nominal operating voltage can cause internal arcing and heat generation that can cause damage to circuits, and with devices becoming smaller and more sophisticated this increases the likelihood of this kind of damage. Often if damage occurs within the devices usually warranty period, the cause may not even be identified. 

So where do these voltage spikes originate?

The most well-known are voltages generated by a lightning strike, either from a direct strike on the building or indirectly from a nearby strike via inductive coupling in the ground.

Smaller voltage spikes are caused by switching, for example grid switching from the power company, or switching on or off of inductive loads. These events are smaller in size but much more frequent. Even something as unlikely as a nearby power cable being cut can lead to a destructive surge.

Overall these are called switching electromagnetic pulses or SEMP’s and it is these smaller, repeated surges that are often the reason why electrical devices mysteriously stop working.

Typical damage caused by a SEMP.

How can we protect our most sensitive equipment?

The Phoenix Contact surge protection philosophy is based upon a three stage concept, with a Type 1 SPD installed at the main incoming power supply, a Type 2 SPD in sub distribution boards or machine control panels, and a Type 3 SPD at end of line equipment. While it is not necessarily as simple as this, a good quality Type 3 device should be used to protect the most sensitive equipment, such as PLCs, PCs, Industrial PCs, Telemetry equipment etc.

For such situations, I would recommend using the perfectly matched combination of a PLUGTRAB SEC surge protection device and latest 4^th generation QUINT power supply. Not only has this combination been fully tested, we now also offer an additional incentive. Should the QUINT4 PSU become damaged in the first 5 years following purchase despite the use of this combination, you will receive a free no quibble replacement.

For more information, contact Mark on 07717 335477 or email mlloyd@phoenixcontact.com