MCC Safe Isolation Simulator: Practise Lockout Tagout Free

The job that must be done in order

A motor control centre, or MCC, packs many starters into one lineup of panels. Each starter sits in a bucket, a drawer that can be withdrawn. Anyone who maintains a plant in India will, sooner or later, have to isolate one of those buckets so that a motor can be worked on. The order of the steps matters, because the wrong order is how people get hurt.

The Substation and MCC lab in the EDWartens Lab lets you practise this order in a 3D switchroom. The video above is the short version of the job.

The steps in the clip

The bucket in the lab is a star-delta starter for a 37 kW, 66 A motor. Star-delta means the motor starts on about a third of the voltage and then changes over to delta, which is a common way to start large motors on a 415 V supply.

First you stop the motor. Then you open the isolator. A panel on the screen describes the state in plain words, from connected, where power and control contacts are made, to disconnected, where all contacts are apart and the shutters are closed.

Next you withdraw the unit. Then you fit your own padlock and attach a tag, so that no one else can put the bucket back in service while you are working. At each stage the screen explains what you did and what the state of the motor terminals is, and a button takes you to the next step.

Prove dead before you touch

The last step is the one beginners skip. You open the voltage tester and proving unit and put the probes on the bucket. First you prove the tester on a known live source, because a tester that has failed will read zero on a live conductor. Then you test dead at L1, L2 and L3 to earth and between the phases. Only then is the isolation complete.

A step taken too early is refused

If you try to do a step before its time, such as padlocking before the unit is withdrawn, the lab refuses it and counts it against you. That feedback is the point. On a real site there is no refusal, only a permit to work system and your own habits, so it is worth building those habits where a mistake is free.

Who should use it

Electrical and instrumentation students, apprentices, maintenance technicians and anyone preparing for plant work. The lab does not replace your employer's procedures or training, and it is not a safety qualification. It is a safe place to rehearse the order until it feels natural.

Try the isolation

Open the lab, choose the Substation and MCC job and do the isolation without hints, then repeat it and aim for no refused steps. Open the free MCC isolation lab in your browser.

It is free to start and runs in your browser.

If you would rather practise this on PLC training panels with an instructor, see our PLC course in Bangalore for the syllabus and duration.