+ 0 Votes prepared for anything brian 3 years ago yeah, a big generator would be recommended for that application (something that sits outside and runs off diesel like you see hidden in many large city parks)...by using a generator in theory you could run the critical systems indefinatly (as long as you have a fuel supply). + 0 Votes I just use Kenone 3 years ago an Eaton UPS that gives me a theoretical 11 hours of runtime (13 servers most virtual) and an orderly shut down after the batteries run to 15%. So far the longest outage I've weathered has been about 6 hours, no problems. + 0 Votes LOTS of variables here robo_dev 3 years ago At a high level, you need to determine exactly how much power your devices require and how much runtime you need. And you need to figure out your budget. Off the top of my head, when you say 'any outage', that takes the price tag from several thousand to many tens of thousands. For a couple of thousand, a nice rack-mount 3KVA UPS for your server would probably run it for a couple of hours, and another 3KVA unit would run most phone systems for an hour or so. APC makes a product line called Symmetra that is scalable, you just add more battery modules. http://www.apc.com/tools/ups_selector/index.cfm Some phone systems, especially legacy ones, need a lot more power than 3KVA. However most legacy phone systems already have a UPS built into the cabinet. If you're talking about 'any outage', then you would need a generator with fuel tank (or natural gas supply), an automatic transfer switch, a bank of batteries, and the related chargers, etc. etc. Easily well over $30-40K. + 0 Votes This Web Site Utility from APC OH Smeg 3 years ago May be a starting point for you http://www.apc.com/sizing/selectors.cfm Click on UPS enter your Country and then fill in the forms and you have a basic starting point. But the reality is first you need to know how long you are planning for a Power Outage and how much power that you need for what has to be run. Most long term Mains Replacement involves Generators or Solar Arrays depending on your location on the globe. Col + 0 Votes General idea TobiF 3 years ago Define a diesel, which will be able to keep everything running (with margins, of course.) Next figure out, what is the longest time needed to start the diesel. This time you need to cover with UPS. (again, with good margins, obviously, since systems tend to grow over time) If your system is really important, don't forget about redundancy. Either 2 units, each of which can cover all the need, or 3 servers, for half the total capacity each. For servers, which are not mission critical, it may be enough to have UPS cover enough time for an emergency back-up of live data and/or controlled shut-down. + 0 Votes The cover-all jck 3 years ago If you need a solution to maintain uptime no matter what, your solution is going to have to be a power generation system. You'd be able to get away with something pretty basic. You don't have tons of stuff to keep online. You will just need to work with some firm to make sure you have an auto-start system in place that will kick in the generator in the event of an outage, and provide power to the facility for a period of time after the power returns from the grid. It's not a cheap solution (compared to battery backup). But for mission-critical systems that could be without mains power for 1 hour or more, backup generation is the best option to ensure you can stay up for longer periods of time. + 0 Votes I just use Kenone 3 years ago an Eaton UPS that gives me a theoretical 11 hours of runtime (13 servers most virtual) and an orderly shut down after the batteries run to 15%. So far the longest outage I've weathered has been about 6 hours, no problems.