Server room power requirements: Strategy for electrical circuits and outlets.
What's so complicated about power? Plug in the machine and watch the LED lights come to life. Unfortunately power supply planning is a bit more involved. Larger server rooms typically have 110V and 220V outlets. To simplify the process we'll examine typical 110V outlets and how they supply appropriate power to the sever room.
Assessment Planning: Layer 1 may not be glamorous but it is the essential foundation for all server room dependencies. Don't assume that server room outlets can support every device you can throw at it. Likewise, it's poor practice to substitute power strips when there appears to be a shortage of electrical outlets. An assessment of available electric resources will avoid these pitfalls.
Visio. Begin the assessment by conceptualizing the server room into a Microsoft Visio diagram. The diagram does not have to be to scale. We're simply mapping electrical outlets and basic server locations. This is an example of a server room circuit map I had previously created:
N.B., 110 outlets are represented with a singular power symbol. 220 outlets are represented with the power symbol and with "240V". The 240V stencil is nominal for either 208 or 240 Volts. APC UPS units, however, can be configured with inputs and outputs of nominal 220, 230, and 240 voltages. Like wise, 110V usually refers to nominal 120V.Power Formula. Visio mapped the 110V and 220V outlets in the server room. Each outlet should then be assessed to ensure a sufficient supply of electricity. On average, 110V outlets can support approximately 1440 Watts, or 1.4kW. The standard power formula is used to estimate an appropriate devices-to-power ratio:
P = I x E
P = Power, I = Current, E = Volts
Use the power formula for server room electricity consumption:
There are a number of methods to estimate power consumption. Amazon sells a variety of tools to determine electrical load. A popular (and low-tech) device is called the kill-a-watt and sells for $30:
APC UPS management cards may also provide power consumption data. The following UPS log shows the output for Voltages and Watts (as a percentage):
Planning for appropriate server room power is the precursor to assessing uninterrupted backup power supplies...