How to Select, Manage, and Measure 3 Phase PDUs

Annie Paquette
September 23, 2019

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We wanted to spend a little more time talking about 3 phase PDUs, so for this blog, we went back to the studio for another conversation with our Senior Director of Power Product Management, Calvin Nicholson. Below are some excerpts from our conversation about selecting, managing, and measuring 3 phase PDUs.

AP:  Good to see you again. Let’s jump right in. When you think about three-phase PDUs, what are your suggestions for going about selecting the right PDU? 

CN:  Yeah, no problem, thanks Annie. So yeah, it is a good question because there is a lot that can go into picking the right PDU. I guess I kind of think about the steps that go into using our BYOPDU tool, which we use in-house, you know. It takes you through the process by selecting the right voltage, amperage, and configuration options for receptacles, and all that. The tool really streamlines the selection process.

AP:  So, besides the configuration tool, what is it that you think people don’t think about or maybe don’t know about picking a three-phase unit?

CN: Yeah, right. There are a couple of things there, maybe not related. First, the way our three-phase PDUs – and single-phase PDUs for that matter – are built, there is an inline power module that allows you to pick different receptacle types. This is a good thing to know even when you are at the stage of just configuring a rack, because you don’t have to be stuck with one receptacle type. It’s not like you have to be stuck with C19s all the way or too many C13's. You can mix the blocks to match the cord types for the equipment in that part of the rack. That is really cool.

AP:  I agree. And you said there were two things?

CN:  Yeah, so the other thing that people need to think about is the power side. It is key to not only plan for the load, which is important for sizing, of course, but you also have to plan for redundancy, too. It is pretty well understood in the electrical world that you size for 40% utilization with redundant UPS or backup power equipment, but sometimes people forget that the same logic applies to three-phase rack PDUs, too. Capacity planning at the rack level is just as important as the rest of the data center.

AP:  Gotcha. And once the unit is installed and operating, what do you think about when it comes to the management of the unit?

CN:  So, when it comes to management, I think about all of the intelligence features that are built into our units. Customers have access to all of the power, load, and usage data through Power IQ, that kind of thing. I also know that there are a lot of details that are engineered into our three-phase units that make them easier to manage. For example, the network cards in our units are hot-swappable, which means that they can be removed and replaced even when the unit is in use. And environmental monitoring like temperature and humidity are there basically free with the unit. It’s like a bonus.

AP:  I don’t think that we sell it for free, but I know what you mean. Is there anything else that comes to mind? 

CN:  Yeah, definitely the intelligent features. We try to make the setup, configuration, installation, and integration of our units into a new room or {existing room} as simple as possible. Whether you use a start-up stick or PIQ software, you can preconfigure our PDUs and then deploy that particular configuration across the network. It makes it easy to manage, but we think it also provides a way to improve the reliability of the operation as well. Our PDUs are sort of like the last line of defense in the war on downtime.

AP:  Well said. So, let’s wrap up by talking about data center loads. I know we have touched on some intelligence features, but what would you say is most important about taking measurements at the PDU?

CN:  Yeah, so load measurement at the rack level is a really big thing. It is another way that people can take control of improving uptime – whether it is at the outlet or device level, they can get power measurements and load information in real-time. Having that data and watching it over time is really the key. In fact, our customers look at temperatures and power trends to help locate stranded capacity within their electrical system. The same measurements can be used to do capacity planning on both the electrical and mechanical side of things. You can locate hot spots, things like that. So, measuring three-phase PDUS is a big thing, and you have to take action on what you are measuring to make the data valuable.

AP:  That’s so true. Calvin, thanks for your time. It’s been a pleasure.

CN:  Thanks, Annie. Good talking to you, too.

Take a new look at 3-phase power distribution: watch the video and view the executive summary

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