Transformer Sampling Danger
May 21st, 2009
MIDWEST is frequently asked if it is safe to take an oil sample from a sample valve under the secondary cables of a pad mount transformer while the transformer is still energized? No, it is not safe. Do not do it. We think it is extremely dangerous. This is the location of possibly one of the most dangerous arc flash hazards in a facility. You can’t wear enough PPE to protect yourself. Keep away from the secondary. Just opening the door to inspect it can be very dangerous. In addition, you would be exposed to unsafe shock hazard. Our recommendation is to sample the transformer during a scheduled outage. We know very well in years past this was common practice for many service companies. Those days are gone. As they should be.
Trouble is many people aren’t aware of the dangers involved.
Of the some 2000 people a year injured in the US most don’t know how dangerous arc flashes are and some don’t even know they exist.