Isolation, Lockout, Tag and Test - The Fundamental Intent

I keep getting asked by apprentices preparing for Capstone which way they should do their isolation procedure.  And there it is, that word ….. “procedure”.  I really don’t like to have a procedure for isolations as that means that I have to doggedly follow it and we all know that rarely two situations are same.  Also, procedures can be too prescriptive and not adaptable, so what do you do?

Intent and Action

I look at the whole isolate, lockout, tag and test scenario as a series of actions to allow me to get to my job, which is fixing or wiring things.  So I consider two things.  What is my intent? And what is my required action?  An example:





I want to work on this switchboard.

Get permission.


Is it live?

Test a few components to see.


It’s live, I don’t want it energised.

Turn off circuit breakers shedding the load.  Isolate.


I want to make sure it doesn’t get turned on.

Lockout and tag.


Am I sure it is dead?

Test all breakers, both sides of the breakers and all components.


Is my tester working?

Check it on a known source.


Ok, so there isn’t a lot of detail.  You adapt as you go.  Say in #2 you do not find any live components?  Then you will need to test your meter to check it is working, on the other hand if they are live then you’ve just tested your meter.  Shedding the load is not a biggie (unless there is a lot of load!) but it is good practice.  Lockout is with a locking device or a padlock or a combination of both, I haven’t mentioned scissor locks, boxes and permits as I’m looking at a generic scenario that you would get in Capstone.


Don’t get wound up trying to adhere to a lengthy procedure, you’ll only end up missing a step and that will shake your confidence.  Keep it simple like the steps above and think of what and why I am doing this.

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