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ITFrequently Asked Questions · UPS
UPS or surge protection strips (surge arresters): what is the difference?
Surge protection strips protect equipment from overvoltages and voltage spikes, and some also filter noise. They do not protect against undervoltage or power cuts, and they give no runtime. A UPS keeps equipment running during a cut and, depending on its type, also corrects the voltage. So they serve different needs and are often used together.
A surge protection strip usually contains varistors, components that clip short voltage spikes and divert them to earth. It only acts when the voltage rises sharply for a very short time. If the voltage drops, the power goes out, or the voltage stays out of range for a while, it does nothing, and the computer shuts down abruptly, with a risk of data loss.
A UPS covers these gaps: it supplies the load from its battery during an outage and, depending on the topology, corrects voltage fluctuations. Most UPS units also include surge protection. Some surge strips do have a noise filter, but none provides runtime.
In practice the two are combined. A surge strip is enough for a TV, chargers or a printer, where an outage is merely an inconvenience. Computers, NAS devices, routers and anything that stores data or must stay connected deserve a UPS.
A common mistake is plugging the UPS into a surge strip, or adding a surge strip to the UPS output to connect more devices. This can overload the UPS or interfere with how it works. Plug the UPS directly into the wall socket.
