Electrical safety: A firsthand account
An error in a lockout/tagout procedure resulted in electrical safety hazards
In an interview with electrical and instrumentation supervisor, Jasyn Hiller, RSE, De Beers Canada Inc., he shared a case he was familiar with about electricians performing lockout/tagout (LOTO) correctly, which proceeded to result in a shock hazard. Hiller recounted that these electricians were in the process of removing a motor control center (MCC). They had locked out the main source of energy to the MCC, then tested and confirmed absence of voltage. Having confirmed the LOTO of the MCC, the electricians began to cut the cables feeding the MCC to field equipment.
As the electricians head nearly completed through cutting the MCC section, they ran into a live cable. This created an unforeseen hazard as the cable had fed from an alternate source that went into this MCC. The live cable did not make electrical contact to the equipment or to the MCC itself. Essentially, as Hiller describes, “it was used as a junction box, inline spliced in one of the cable ways.”
Hiller described this as a unique situation and said it was like a trap that the team got caught in. “It went in and out and that was obviously not picked up in your conventional test for dead procedure,” he said. “It was obviously not installed to electrical code and the equipment wasn’t labeled as fit from an alternate source nor were the drawings updated to reflect the fact that a cable had entered and left that equipment.”
Hiller has nearly 15 years of experience of electrical work in mining. This is just one of the many challenges he has encountered over those years, each one requiring a control to prevent predictable and unpredictable scenarios from occurring again.
An important aspect of these scenarios to note about mining electrical safety that statistics may not always reflect is that many of these situations do not have the necessary experienced and knowledgeable staff to manage their operations. Mining operations typically have small crews of electricians or use contract electricians that do not necessarily have industry specific experience.
This is reflective with mining’s electrical fatality rate that is 8-12 times higher than other industries across the U.S., with 1 out of 22 electrical injuries mining results in death. This number is staggering considering all other mining-related injuries result in one death per 203 injuries. Nearly 75% of these electrical injuries and deaths happen while personnel are operating frequently used machines, tools, appliances or lighting.
The reality is that a margin of human error, pressures for minimal downtime and small, inexperienced crew operations will always exist. These statistics demonstrate the need to go beyond regulated compliance within these dangerous, volatile and unpredictable environments.
“Control of hazardous energy” is one of the most cited violations each year by Occupational Safety and Health Administration. An industry that slants toward higher-than-average risk regarding electrical safety would benefit greatly from the safety and productivity enhancements provided by permanent electrical safety devices.