Question: 28 Devices in Rack… Can I Power with One Circuit?
I have an application where I am putting 28 small devices into a rack. Can I power them all from one circuit? I want to use a 20 receptacle power strip and a 10 receptacle power strip plugged into the same wall outlet.
Generally speaking, people can fall into a trap by assuming that just because they have a large number of receptacles, that means they can fill up a power strip and not worry. Unfortunately, such is not the case.
A single 15Amp circuit, like the one in your wall at the office or at home, can provide 12 amps of continuous, steady state power. Having two receptacles in the wall does not double the amount of power available, since the wall receptacles are powered from one wire, and represent a single circuit. To tell how many units can be powered by a single circuit, you need to add the amperage that each unit pulls. Once you get to 12, you stop adding units to the power strip. If you go over 12, disconnect the smallest (by power used) component, to get to 12 exactly, or just below. Power strips with current monitors are excellent for helping you determine how much current a group of components is pulling. Any extra receptacles should remain unused. They can be closed off with plastic outlet plugs.
The problem with plugging in too many units is that each unit will be underpowered. It may still appear to operate fine, but it may not be getting the correct power needed to operate properly. If it is a computer or server, less than proper power can cause data loss and other problems.
Putting 28 small devices in a rack is OK, as long as each device averages .428 amps (12 divided by 28) or less. Since there are a lot of devices out there that only require about .4 amps, this should be OK.
Note that if you have a 20Amp circuit, then the continuous amperage available is 16 amps.
Thanks for your question!
Rackmount Ranger
