Previously, we addressed characteristics you need to know before entering the IT room. But what about working in the IT room? Here are some tips you should follow once you’re inside the room:
*Normally, lockout/tagout of supply breakers ensures you have removed electrical energy from the circuits you’re working on. But normally, circuits don’t have battery backup unless they are IT circuits. And in that case, they normally stay energized even if you open the supply breaker. You must disconnect the power to the final load; open all disconnects to UPS-supplied equipment. Then use a DMM to verify each one is de-energized. Apply the appropriate locks and tags to keep them that way until you’ve completed your work.
*Due to many misguided “grounding” schemes, de-energized equipment can still present lethal shock hazards. To eliminate differences in potential, bond “separate” grounding systems (e.g., network and power).
*Misguided “grounding” schemes can also leave lethal potential between network cable shields and equipment enclosures. Don’t touch cable shields until you’ve verified everything’s properly bonded.
