A salutary tale emerged from Clonakilty this week on the vagaries of our power supply in West Cork. At about 10:00 on Monday morning there was a power cut in Clonakilty town centre. To protect against outages you need to:

1. Make sure your equipment is protected from the power surges that result when the power comes back on.
2. Use an uninteruptable power supply to protect your data. 

With all this 'protection' around you'd wonder why anyone would have a problem during a power cut.

A UPS contains a number of batteries and the computer equipment is powered through the UPS, if the power goes out the UPS continues to supply the computer equipment until power is restored. Of course the batteries only last a relatively short length of time, depending on the rating of the UPS, and so it's good practice to shut down the computer's while there's still power remaining.

Firstly a UPS is not a power surge protector, even though you may think it should act as one. Also the UPS itself is vulnerable to power spikes and surges. Even though one client had their servers protected by a UPS they lost one of their PCs when the power returned. An investigation showed characteristic deposits on tops of the motherboard capacitors where they'd boiled their insides. The power supply unit (PSU) was also dead (no surprise there). While it's possible that the PSU would have failed anyway; it's demise was certainly enhanced by running unprotected from spikes.

Second client was also protected by a UPS. The power went off - and the UPS went off. The UPS was several years old (like about 7 or 8) and the batteries simply weren't holding any charge anymore. The simple answer here is to test the equipment periodically, monthly is probably good, just to make sure it's doing what it's supposed to be doing.