Lock Out / Tag Out for Solar Photovoltaic
June 20, 2011
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Today Travis, Gord, and Alain installed the Programable Logic Controller (PLC) system they designed to monitor the solar photovoltaic. Photovoltaic panels are the solar panels that produce electricity. Since there is electricity involved extra precautions need to be taken when doing work on the system. Lock Out / Tag Out is a procedure that involves turning off all sources of electricity and locking them in the off position with a padlock. It also requires a tag be added to the lock explaining what is happening. The key to the lock is kept so that only the person performing the work can turn the equipment back on. This prevents someone from inadvertently turning the power back on and electrocuting those doing the work. Gord Wilkie presented the procedure to Gary Williamson who is the facility manager and it was approved.
The lock out / tag out procedure was:
1) Open the solar AC disconnect and lock and tag.
2) Open the solar DC disconnect and lock and tag.
3) Securely cover solar panels with an opaque tarp.
4) Measure DC strings and ensure voltages are at zero.
5) Issue work permit.
Once the work permit was issued they installed the PLC monitoring system.
When they were finished the steps were:
1) Surrender the work permit.
2) Ensure all covers on monitoring box are in place.
3) Remove tarp from solar panels.
4) Close solar DC disconnect by removing the lock and tag.
5) Close solar AC disconnect by removing the lock and tag.
Safety is paramount when working with high voltage and I am happy to report that nobody way hurt. Their PLC system is working and we will start getting data immediately.
Solar panels covered by a tarp