Any significant down time at my data centers could potentially cost my company millions of dollars in lost revenue, so I looked for every possible problem area and implemented preventative maintenance measures to ensure that downtimes were either minimized or eliminated. One of these preventative maintenance measures was to pre-test all branch circuit breakers prior to installation.
The last lines of defense protecting your critical servers on the raised floor are the branch circuit breakers that are located in your PDU/RPP’s. Considering how many of these are produced each day regardless of the brand name, you can be sure some of them may have defects. This can lead to several problems. If the branch circuit breaker does not trip on a direct short the next breaker in line will be the main breaker in your 42 circuit panel which can lead to widespread failures of your critical servers on the raised floor. In the event of an overloaded circuit, if the individual branch breaker does not trip, over time it can cause a fire.
I found from my years of experience of testing the branch circuit breakers that we installed in our data centers that between overloaded branch circuits and direct shorts we found about a 4% failure rate. Even though 4% may not seem like a large percentage, in most data centers 4% of the thousands of circuit breakers used can still put a significant number of servers at risk.
The solution I implemented and I recommend to you is, purchase a circuit breaker tester, set up a test station onsite and send some of your people to a training class so you can test all of the branch circuit breakers in-house prior to installing them in your critical environment. If that is not an option then you should consider having a local vendor do the testing for you. For each circuit breaker that passed its test we stickered, dated, signed, and then inventoried them for future installation.
Another very important maintenance practice is to exercise these breakers at least every two years when you have the opportunity to shut down the PDU/RPP for your scheduled maintenance program. I recommend that you exercise each branch circuit breaker by turning them off and on at least three to four times. This will ensure the breaker does not become seized in the closed position which could prohibit them from tripping in the event of a direct short or overloaded circuit which can lead to the above mentioned problems.
If it is continuous uptime you are looking to achieve, along with a good maintenance program, testing and exercising branch circuit breakers is a preventative maintenance measure well worth implementing.