# Network UPS backup time
**URL:** https://boards.straightdope.com/t/network-ups-backup-time/940620
**Category:** In My Humble Opinion
**Created:** [April 23, 2021, 2:59pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620 "2021-04-23T14:59:23Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)
#### Post date: [April 23, 2021, 2:59pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/1 "2021-04-23T14:59:23Z")
How long will UPS keep your network switches and servers running?
I’ve been asked to some up with a number. If the users don’t have UPS as well, I think an hour would be plenty of time to shut things down without loss or damage.
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### Author:  [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)
#### Post date: [April 23, 2021, 3:18pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/2 "2021-04-23T15:18:16Z")
There’s no one answer. You really need to make a list of the servers and switches you want on the UPS and determine how much load they draw. Based on that, you can specify an appropriate UPS. APC is a manufacturer of these things and they have a tool on their website to help you choose an appropriate UPS.
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### Author:  [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)
#### Post date: [April 23, 2021, 3:33pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/3 "2021-04-23T15:33:23Z")
We are dealing with a contractor. I don’t want them to fleece us, and they are asking how long we want the network to stay up. I’m going to go with two hours.
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### Author:  [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)
#### Post date: [April 23, 2021, 3:41pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/4 "2021-04-23T15:41:56Z")
OK, so presumably they will make the calculations and specify an appropriate UPS. It’s possible you may want a UPS that’s capable to two hours of backup even if you have twice the amount of equipment you presently have (to allow for growth).
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### Author:  [@Omar\_Little](https://boards.straightdope.com/u/Omar_Little)
#### Post date: [April 23, 2021, 4:46pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/5 "2021-04-23T16:46:50Z")
It depends on what you need the back up power supply for.
If it is just so you can make appropriate back-ups for your server, then the time needed may be as you suggested.
If you are a trading company, you may want your backup power supply to allow your trading professionals to stay connected to their markets for the rest of the trading day or more.
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### Author:  [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)
#### Post date: [April 23, 2021, 5:00pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/6 "2021-04-23T17:00:23Z")
Another consideration - are all of your network devices in the same rack? Or, like most networks, do you have switches and access points scattered around the building? It does no good to have a server running if the users can’t access wifi. And if you have traditional desktop PCs that need access, they will need UPS power as well.
As Omar\_Little asked, are you looking to stay running as normal through a power failure of up to xx hours, or do you just need enough time to initiate an orderly shutdown that’s automatically triggered by the UPS going to battery power? The necessary runtimes and costs are very different.
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### Author:  [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)
#### Post date: [April 23, 2021, 6:04pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/7 "2021-04-23T18:04:02Z")
> [@gotpasswords](#):
>
> It does no good to have a server running if the users can’t access wifi.
Some folks don’t seem to understand that.
Each building has a switch rack.
I’m going with two hours. I had no idea much POE is used for wireless access points
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### Author:  [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)
#### Post date: [April 23, 2021, 7:55pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/8 "2021-04-23T19:55:08Z")
At the datacenters I’ve worked, two-ish hrs was the norm. Though in reality, the longest we ever ran on the UPS was like 3ish seconds. Long enough for the generators to start.
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### Author:  [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)
#### Post date: [April 23, 2021, 9:29pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/9 "2021-04-23T21:29:35Z")
Thanks, I submitted the load info with two hours.
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### Author:  [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)
#### Post date: [April 23, 2021, 11:49pm UTC](https://boards.straightdope.com/t/network-ups-backup-time/940620/10 "2021-04-23T23:49:55Z")
Back to POE, I looked at all the switches, and some 33W switches are pushing out 200W of POE for wireless access points.