To determine how many Dell PowerEdge servers can be plugged into powerstrips, you need to calculate the operational range for a single server and determine the amperage.
Question: I have several Dell PE2950 Servers and several 20A powerstrips, my facility provides 120VAC. How many PE2950’s can I plug into the 20A Powerstrip without tripping the breaker?
Answer: The Dell PE2950 has a manufacturer’s rating of 750W, however this rating can vary by +/- 20% depending upon the operating efficiency of the primary power supply. The operating efficiency is mainly affected by temperature but there are a host of other things that can affect the operation as well.
First, you start by calculating an operational range for a single server:
- 750W + 20% = 900W
- 750W – 20% = 600W
The next step is to determine the Amperage (W/VAC=A):
- 900W/120VAC = 7.5A (max)
- 750W/120VAC = 6.25A (spec)
- 600W/120VAC = 5A (min)
The operating load of the powerstrips must be determined. This is where the 20% variation in operating efficiency is important. If you load the powerstrips over 80% you can run the risk of overloading the breaker under a maximum load.
- 20A * 80% = 16A
- 20A * 85% = 17A
- 20A * 90% = 18A
Using these guidelines you can easily determine how many PE2950’s you can plug into your 20A powerstrips:
- 7.5A * 2 = 15A (max load)
- 6.25A * 2 = 12.5A (spec)
- 5A * 3 = 15A (min load)