We have an automation group and one thing we struggle with is procedures for them to get access to energized control panels to do control circuit testing. These panels can range anywhere from having 480V incoming to only 24V. A good majority of the time, there is 480V incoming and a transformer dropping the voltage to 120V or 24V. The automation techs will be testing the components on the secondary side of the control transformer.

NFPA 70E would say full PPE if working in the boundaries, but in the real world, this isn't always practical. For example, we built a control panel and it was installed at a customer facility. After an electrician installed it to the 480V coming in, the automation techs went out to do the testing of the controls. The panel was opened up, a table with laptop setup in the front of the panel, and ethernet tied into the PLC. They spent the entire day in front of this panel doing testing. Every so often someone would take a meter and test one of the terminal points to see if it was firing.

What would be a good procedure for performing this type of testing but remaining within a sphere of safety? What does everyone else do in this situation?

TIA

It starts w/ design...if you barrier off or separate the 480V incoming to the "control power side", then life is good.

In cases where you don't have barriers, it's then a judgment call based on what is being worked on, distance to differing voltages, etc.

Mike