Check Applicable Up-to-Date Drawings

This clause from CSA Z462 4.2.1(a) is the first step in establishing an electrically safe work condition. It states: “Determine all possible

sources of electrical supply to the specific equipment. Check applicable up-to-date drawings, diagrams, and identification tags”.

When I get to this clause at my safety classes, I ask the class how up-to-date their drawings are, then listen to the group laugh when someone says, “What drawings?”

Last week, a couple of friends were troubleshooting a refrigeration unit that was only nine years old yet had horrible schematics and no documentation. They were stumped until finally an HVAC specialist arrived to show them where the low gas pressure reset was hiding. A quick cleaning of a connection and they were up and running.

The problem we now have as organizations, managers and supervisors is huge: had one of my friends been electrocuted, you can bet the investigators would ask to see up-to- date drawings. Since there were none, the supervisor, organization and the surviving co-worker would have found themselves in an indefensible situation.

4.2.1 (a) and other Z462 clauses reference up-to-date drawings during planning and when establishing an electrically safe work condition prior to applying lockout devices. Troubleshooting a live circuit is obviously excluded from these scenarios, but there is nothing dictating that an investigator not expect up-to-date drawings to be both handy and with clear evidence of use. As senior electricians, we are the largest part of the problem. Since out-of-date or missing drawings are the norm, we don’t see anything unusual, and continue to live with the situation rather than advocate for correcting the situation.

When you have equipment lacking “up-to-date drawings, diagrams and identification tags”—and you have troubleshooters testing its energized circuits to identify causes of failure—then you need to conduct an audit. Rate your equipment based on its complexity, voltage levels, MTBF (mean time between failures) from electrical causes, remaining life, junction boxes, connection points and what it would take to get it diagrammed. Invoke this as the mandatory safety requirement that it is, and start pressing for the budget money. We have missed 2010 so let us collectively aim for 2011.

Arc flashes have driven monumental change in our electrical industry, but electrocution is still our greatest risk. “Up-to-date drawings, diagrams and identification tags” are nothing more than road maps that significantly reduce troubleshooting time and, most importantly, help prevent needless injury.

Until next time, be ready, be careful and be safe.