You must understand that a person’s body is an extension of the electrical system, and you really have no idea what will happen when touching that person.
Most workers are trained in hazardous gases and confined spaces; they do know that, when someone is down and out in a confined space, they must not execute a rescue because it’s dangerous – regardless of their excitation level.
The same thinking must be learned about a person in contact with an electrical system.
Electric hand tool electrocutions are rare nowadays but, before the 1971 introduction of double-insulated (DI) – and recent developments in battery-operated (BO) tools – they caused many deaths. When a person was holding a metal hand tool that became energized – and were grounded with the other hand – it would be very difficult to rescue this person, as they would be tightly clamped to both the energized tool and the ground point. In this case, swiftly unplugging the tool is the correct response.
Companies assume all their workers use DI or BO tools, but an audit will always discover angle grinders, recip saws and other metal tools. Contract workers, especially welders, are a concern during tool audits.
It is actually simple and inexpensive to have a tool and appliance tester set up at the tool crib to ensure all metal-cased electrical tools – drill presses, chop saws, etc. – are insulation-resistance (IR) tested at regular intervals. In 31 years, I have only come across one company that also sets aside one day a year for workers to bring in their personal tools to the plant to be IR tested.
As an electrical worker, you want to ensure everyone around you knows how to effectively rescue you.
I was teaching in a facility where a young student was pleased-as-punch because, a week prior, he had saved an electrician who was hung up in a panel. He said that, even though he had saved the man, the electrician was furious because the student smacked him with a 2x4 and broke the electrician’s arm.
In your moment of need, you don’t want the rescue plan to look like this:Grab nearest 2x4Hit victim really hard with 2x4
Instead, you want everyone around you to understand clearly how to properly perform an electrical rescue.
When you’re in a substation, you should always know from where electricity is being fed, and the location of the main disconnects. You should also know the various voltage systems; for instance, an indoor substation could have 25kV, 15kV, 5kV, 600V, 480V and below. Most of these should be shown on a single-line diagram that is required to be prominently posted in the station. When you do not know what is there and where it is, you are not qualified to be in the station alone.
You should also know how to disconnect each of these systems; the single-line diagram will identify all the disconnect points, but will not provide their actual locations in the substation. You should always note where they are in case of an emergency.
When you’re working in an electrical room with panels and MCCs, you should always know how to disconnect them. When you’re working around a piece of machinery, you should know where to find the main disconnect.
Astute companies will have main disconnects clearly identified so that, should an electrical rescue have to be performed, any worker can quickly and immediately go to the source of the power. They will also have electrical rescue hooks beside all panels.
Until next time, be ready, be careful and be safe.