Why do companies look for a Tier III data center? Should companies look for a Tier III data center to provide colocation hosting? Before that question is answered do you know what a Tier III data center is and how Tier designations have been designed? iStreet is frequently asked if our data center is Tier III. Yes, The iStreet power infrastructure is concurrently maintainable. We feature true A/B power delivery with physical separations for the A & B UPS, PDU, and ATS systems, dual substation feeds and power delivery for increasingly dense computing platforms. We can deliver both single phase and three phase power.
So what is a Tier III data center? Let’s go right to the source of the definition, the Uptime Institute. It states a Tier III data center is built with a concurrently maintainable power infrastructure. To simplify, that means the data center has redundant components with a minimum of two independent power distribution pathways, A / B, to your servers.
Only one distribution path is required to serve the computer equipment at any time. For single corded equipment this dual path presents an A only power configuration. For dual corded equipment, power can be supplied in an A + B arrangement, or for fault tolerance an A or B arrangement.
Let's translate that into something we can use: if you have fault tolerant equipment requiring 12 Amps for each power supply, you would use an A or B configuration with two 208V 30Amps circuits. So if the circuit on the B side fails, its 12 amps can be switched over to the A side. The A side will take over the load, now 24 amps, and be within code tolerances.
It is often overlooked and risk is added to the power equation when other load is placed on the A and B side other than that of the critical equipment. As an example, if A and B are loaded now to 18 Amps and eitehr the UPS or power supply fail, A would be required to power 36 Amps of equipment! This far exceeds the safe loading of the circuit certianly causing it to trip. Word to the wise “Don’t do that”!
However, it is observed that powering dual power supplies is done by plugging in both power cords into the same circuit. The result here is a power supply failure would not add load to the overall power available.
So where does Tier III come into play? In the scenario above, it means that during maintenance, power is still provided. The equipment still runs as required!