And Then the Lights Went Out
Dave Smith has been an Industrial Maintenance Electrician since 1975. He has taught maintenance, troubleshooting and safety courses to thousands of electricians in mines, mills, refineries, factories, plants, power stations and offshore platforms throughout North America and the Middle East. Dave is a hands-on guy and teache...
May 2010
By Dave Smith
Indeed, something as simple as an additional section on a switching order can
prevent a small situation from turning into a catastrophe.
The two substation electricians were in their fourth decade of working
together, and they were hilarious to listen to. I was doing a training program
at a 500kV substation and these two had inadvertently re-energized into a set
of grounds and turned the lights off to a small city.
They were naturally in deep doodoo with higher ups who wanted heads to roll.
Naturally the first blamed the second and the second, nonchalantly,
reflected the blame back to the first.
What had happened is that these two normally install two sets of grounds to
create an equipotential grounding system but, in this instance, the first
person decided to install a third set of grounds. Two mistakes, in fact, were
made: the first was he didn’t inform the second worker that he was being extra
safe that day, and the second was he put the extra set behind a piece of
equipment in the substation where it could not easily be seen.
When the second worker went to remove the grounds, he removed the two sets he
could see and never realized there was a third set. When they reenergized, you
can imagine the chaos: protective devices slammed off, and this installed set
of grounds was whipping and snapping like electrified snakes.
There are a number of controls we have in place to avoid situations like
this, one of which is to have the individual who installed the grounds also
remove them. This isn’t always the case, so we need extra controls. Better
documentation key Grounds have to be listed on your switching orders; when you
have a system over 750V, you will need switching orders (unless you have a very
simple system). When there is complexity, you need to have a series of
documents (prepared prior to the work being done) that form your switching
orders. These documents involve the workers performing the task, and should be
reviewed by a competent third party (often the supervisor).
The error that was embedded in the organization of the above job was simple to
locate. There was a section in the form that said “Grounds Installed”, and a
check box next to it. Of course, the box was checked. There was another section
for “Grounds Removed” with an accompanying check box. It, too, was checked.
Needless to say, there was no section in the form where someone could indicate
the number of grounds installed, nor jot down the number of grounds removed.
Had something like that existed, the second worker would have instantly noticed
something was out of the ordinary (three grounds instead of the usual two). He
would have questioned his coworker and learned of the hidden third set of
grounds.
Because of a very small, and easily preventable mishap, an entire town
experienced a blackout, which is more than just an opportunity for a romantic
dinner by candlelight. Just think of all the critical processes in
manufacturing, science, etc., that require electricity to power the economy.
Think of critical situations in health care, where someone’s life could hang in
the balance. Indeed, something as simple as an additional section on a
switching order can prevent a small situation from turning into a catastrophe.
The crew at this substation was using a form that was standard throughout the
organization. The surprise is not that this actually happened, but that it has
never happened before. The reenergizing of electrical systems into installed
grounds has, however, happened before, and will happen again.
Take a closer look at your own forms and documentation with an eye toward
uncovering the little things that can make a world of difference.
Until next time, be ready, be careful and be safe©.
Canada Training Group has been providing consulting services to
industry since 1980; Dave Smith, the president, can be reached at
davesmith@canada-training-group.ca.