Why consider an External Surge Filter for your UPS?

A UPS on its own probably won’t provide sufficient Surge Protection

Lightning strikes and associated power surges (spikes) can damage and destroy electronic equipment. What would happen if your computer or server or PLC was damaged? Could you lose some or even all data? Would your plant stop? What cost would that be to your business? Is your equipment adequately protected against these Surges?

Most people rely solely on a UPS as front-line surge protection and yes, a UPS has some basic surge protection built into the unit but that may simply not be enough.

A UPS (Uninterruptible Power Supply) has a primary function to provide some backup supply in case a power outage to enable work to be saved and allow an orderly shutdown of PC’s and small file servers.

The surge protection in a UPS intended for minor surges in the supply by diverting a high voltage spike to ground – there is no protection against high surge currents and these may pass straight through to the connected equipment (Fig. 1). This is particularly so when using a Standby or Line Interactive UPS where the load is normally connected to the mains and will only switch over to the UPS battery when the power supply goes outside a tolerance range.

A large or sudden surge may be well beyond the capabilities of your UPS and is likely to damage the UPS protective circuitry, leaving the UPS without any capability of protecting connected equipment at all – and you won’t know because there is no alarm or warning on most, if not any UPS. It is therefore worth considering additional protection for equipment in your office or plant that can divert the high, destructive energy of a surge before it gets to the UPS.

A Zapguard Pro Surge Filter is a three-stage filter which will divert a high voltage spike to ground as a Primary Surge Protection through parallel path, Limit and Control the Surge Current through a series connected filter component (choke) (Fig 2)

Major Surges may destroy the external filter in case of a “high-line” condition as a result of direct lightning strike. The unit will indicate failure but will offer a limited amount of reserve protection until the filter is replaced. This is a relatively low-cost item compared to a UPS and unlike a UPS is a “self-sacrifice” device that will help to keep your plant and electronic equipment going.


Contact Electronic Power Solution for any additional information