Vital considerations when choosing rack mounted power distros

Rack mounted power distros are instrumental in setting up server rooms and similar applications. However, it’s important to get the right distros for your specific setup – if you rush things and buy the wrong ones, you could end up costing yourself an awful lot of wasted time and money. To help you avoid that scenario, we’ve highlighted some key considerations for you to think about when you’re choosing a server mounted rack mounted power distribution unit (PDU).

How many rack units do you need?

This is one of the first things you’ll need to think about when you come to buy your server cabinet – how big it is in rack units. In case you need a refresher, a single rack unit (RU) is basically the standard for measuring rack-mounted equipment like PDUs. One rack unit is roughly equivalent to 1.75inches, or around 44.5mm. Server racks generally come in sizes of between 40U, 42U, 44U and 48U enclosures (in other words, between approximately 18m to 21m long). Speaking of which…

Make sure to cater for the dimensions and fit

Essentially, you’ll need to make sure that your solution is scalable (a key attribute of our own rubber boxes, by the way). If you fail to take scalability into account, it severely limits your ability to expand capacity in the years to come, so early on in the process you’ll need to work out two things: how much space you need for your existing setup, and how much you’re able to accommodate for in future. Rack mounted LCD monitors, environmental monitoring devices and battery backups are all additional accessories that it’s wise to think about at this stage in the process. You’ll need to pay particular attention to cabinet space to the front and rear. A good rule of thumb is to add 10% more room to allow for future expansions, which should give you plenty of wiggle room.

They’re just a few amongst the many reasons why you need to extensively plan your cabinet from the beginning. Don’t forget about the length of your power cords, either. You don’t have to be an engineer to know how irritating it can be to discover you’ve ordered an item with the wrong cord length, but it’s especially critical in server rooms. Cabling requirements, direction and interconnects all need to be examined in detail. It’s sometimes worth considering having a professional-grade Computer Aided Design produced by an expert, which can help you visualise it in more detail.

Amperage and voltage

We hardly need remind you about these, but they’re so important that it would be remiss of us to leave them off the list! Your amperage will be determined by your power rating, defined as the amount of sustained power draw that a given rack-mounted PDU can handle. Choosing one at the wrong amperage can easily lead to fuses being blown, which might possibly result in an expensive shutdown.

Meanwhile, as far as voltage is concerned, you’ll generally find multiple voltage options for rack PDUs. 208V or 240V are generally the most common for computing gear, so those are the ones to consider first, but they’re far from the only options available. It’s never a bad idea to check your own infrastructure voltage well in advance, just in case.

Power distribution and cooling

Before your server is ready to go you’ll need to consider mounting locations, orientation and cable distribution. This includes the cable arrangements at the back too, which can severely limit the server’s cooling capacity if they’re set up incorrectly. It’s also a good idea to consider blanking options, side panels, separators and brushes, all of which will be instrumental in effective cooling. You’ll also have to think about the locations of the cutouts on the racks – for example, if your power distros are top-fed, your cutouts will need to go on either side.

This isn’t necessarily an exhaustive list, but should give you some good starting points to think about when choosing rack mounted PDUs. If you need any specific advice, our experts are happy to help however we can. Just give us a quick call on 01282 677 910, or alternatively start browsing our very own stock of power distribution boxes!