They all put this PDU @ 24 AMPs. With a 110v 30AMP connection how can I fully utilize it? Am I stuck with a missing 6 AMPs not used? I am a bit confused here.
24 amps refers to the maximum load allowed on a circuit of that type. It's the 80/20 rule where you should only use your circuits up to 80% of the maximum load. On a 20-amp circuit that would be 16 amps, on a 30 amp circuit that would be 24.
Ahh, due to fluctuation in AC correct? So by using this product with a 30 AMP 110v drop I can run around 26 but would be best to stick to 24 and lower?
I am currently at 2 x 20 amp drops. After 15 servers with dual power supplies and 2 switches I am already around 17 amps at idle. I am going to increase these drops to 2 x 30 amps and would like to stick a few more servers but still allow for a couple PDUs to go out on one drop and the second PDU pick up the load.
Quote:
Originally Posted by Neoeclectic
24 amps refers to the maximum load allowed on a circuit of that type. It's the 80/20 rule where you should only use your circuits up to 80% of the maximum load. On a 20-amp circuit that would be 16 amps, on a 30 amp circuit that would be 24.
80/20 has more to do with US electrical code. You can do whatever you want. Run it up to 30amp or 36 (120% but not advisable for obvious reasons).
80/20 is a general rule of thumb when considering uptime and how much load for things such as spikes. You'll find that most data centers with truly redundant applications will do 80/20 while others that do not will only do 50/50 for uptime considerations.
Sometimes to get more density into a rack 250/20 or 30 basically allows double density but at the cost of 2x more circuits. If you're at all concerned about uptime then you need to consider your load distribution and the use of a backup device such as a UPS or a static switch.
I'm a little confused about what you mean by "a couple PDUs to go out on one drop and the second PDU pick up the load."
If I'm reading it correctly multiple PDU's to a single circuit doesn't sound like a good setup. But then again I don't understand what you're saying. To say "PDU" can mean different things to different people depending on the environment they are accustomed to.
In most datacenters a PDU refers to the power distribution unit connected to the main bus of the power plant. These are generally large units that stand about 5' tall and 6' long. Some people like to refer to the strips inside of a cabinet as a PDU but for the most part they are simply power strips.
Solokron,
Sounds like you have dual feeds to your racks, right? Upgrading from 20A to 30A will increase your rated capacity 50%, from 16A to 24A. Since you need to buy new rack PDUs and install new circuits, you may want to think about using 208V, instead of 120V, for better efficiency. If you do this, I recommend using IEC C13 outlets, so that people can't plug 120V appliances into the higher voltage by mistake.
To reduce confusion about PDUs, I usually hear floor-mounted PDUs referred to as stationary PDUs and the power strips as rack PDUs.
That is correct. I have two drops each going into a PDU.
a single pdu? each drop doesn't go into it's own pdu? if that's all you have, that's fine...but if your data center has redundant power feeds, each drop should really come from a pdu off of each feed.
PDU Confusion
