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Recent shock incident at THE EDGE

Hello fellow practitioners.

During the recent packin of Miss Saigon in the Civic Theatre, we had a person get an electric shock from the MALE tapon pins of a Weiland header. Our version of this multi uses a 10 pin connector with a separate pin for each of the 5 circuits phase and neutral wires and a common earth. As these are common across the industry, I thought it prudent to bring this to your attention as the dangers within this set of circumstances are not directly obvious. It has also become apparent to us that a hole in our test and tagging regime did not pick up the fault that led to this incident.

It takes a complex situation to "make" the male tapon pin live, but this situation is common when hot patching and identifying circuits when the fault exists. In our case;

In this situation the load would not light up and the neutral pin of the circuit 2 tapon is live. The person picked up the circuit 2 tapon and got the shock. I have attached a schematic of how this is possible for those that want to study it more closely. If all the other tapons are plugged into dimmers or stacked together, the issue does not occur as the neutrals get common'd this way (and the load lights up).

Clearly this is a dangerous situation and as our test and tag process does not check all the possible combinations of the 10 pin connector, had not been picked up. It is highly possible that it had been like this for a long time but never been used just this way before. We have around 300 of these and so far of the about 200 we have checked have not found any others with the fault.

In addition to the normal PAT test and tagging process, we are building a device that will identify any miss-wiring of the weiland connector. This will check pin for pin for continuity as well as for any crosses. A simple multi meter on continuity test will also work but for us with a large number of these multis we have opted for the more foolproof box.

We were lucky there was no serious harm caused from this incident. The person was on the gallery and was an experienced and qualified electrician. Had the person been atop of a ladder the outcome could have been quite different.

Hope this is helpful

Kerry Griffiiths - Production Manager




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