Red_Skull
Member
- Location
- Austin, TX
- Occupation
- Electrical Engineer
I have a question about lockout procedures when equipment is already de-energized upstream. Our facility has a yearly outage, during which we de-energize the entire building. The maintenance scope for my department includes all of the medium and low voltage switchgear, but not any of the downstream distribution panels, sub panels, MCCs, or production equipment.
The contractor performing the switchgear maintenance opens the breakers at the main substation that supplies the facility, racks them out, and establishes a lock box. They perform their absence of voltage checks at the switchgear and apply temporary grounds. They do a great job every year and we have never had any issues with them. The problem arises with contractors and other departments working downstream during the outage. Last year, we had a near miss when the facility was re-energized. A different contractor had been working in some MCCs all day and had not bothered to LOTO any of them. Luckily they had finished up their work and closed everything up a few minutes before the site was re-energized. This incident has prompted a review of our LOTO procedures.
It's my opinion that anyone working should LOTO locally at the equipment they are working on. The issue arises when someone is performing a LOTO procedure after the facility is already de-energized. Performing an absence of voltage check on the equipment that is already de-energized upstream doesn't really tell you anything. You're going to read zero volts no matter what, but the wrong switch could have been opened or a pole could have failed to open and you wouldn't know any differently. This could just as easily apply to mechanical equipment or control panels. Attempting to start a motor during a LOTO procedure is meaningless when it is going to be de-energized either way. A worker may have a false sense of security thinking that they are locked out, only to have equipment re-energize when the facility is re-energized.
I don't want to have to establish a lockbox for the entire site, if it can be avoided. There are hundreds of contractors and employees working on equipment during the outage. It would be a nightmare finding everyone when it comes time to re-energize. We do make a sitewide announcement when it is time to re-energize, but it can't be heard everywhere in the facility.
I would appreciate it if anyone has any suggestions or feedback. Thanks!
The contractor performing the switchgear maintenance opens the breakers at the main substation that supplies the facility, racks them out, and establishes a lock box. They perform their absence of voltage checks at the switchgear and apply temporary grounds. They do a great job every year and we have never had any issues with them. The problem arises with contractors and other departments working downstream during the outage. Last year, we had a near miss when the facility was re-energized. A different contractor had been working in some MCCs all day and had not bothered to LOTO any of them. Luckily they had finished up their work and closed everything up a few minutes before the site was re-energized. This incident has prompted a review of our LOTO procedures.
It's my opinion that anyone working should LOTO locally at the equipment they are working on. The issue arises when someone is performing a LOTO procedure after the facility is already de-energized. Performing an absence of voltage check on the equipment that is already de-energized upstream doesn't really tell you anything. You're going to read zero volts no matter what, but the wrong switch could have been opened or a pole could have failed to open and you wouldn't know any differently. This could just as easily apply to mechanical equipment or control panels. Attempting to start a motor during a LOTO procedure is meaningless when it is going to be de-energized either way. A worker may have a false sense of security thinking that they are locked out, only to have equipment re-energize when the facility is re-energized.
I don't want to have to establish a lockbox for the entire site, if it can be avoided. There are hundreds of contractors and employees working on equipment during the outage. It would be a nightmare finding everyone when it comes time to re-energize. We do make a sitewide announcement when it is time to re-energize, but it can't be heard everywhere in the facility.
I would appreciate it if anyone has any suggestions or feedback. Thanks!
