EFCOG Electrical Improvement Project Electrical Hazards Awareness Briefing Excavation and Trenching Module 5

EFCOG Electrical Improvement Project These tools must be used with care!

EFCOG Electrical Improvement Project Serious Injury at DOE Site when 13.2kV Cable Struck A laborer was burned and rendered unconscious when his jackhammer hit a buried 13,200 volt electrical power cable.

EFCOG Electrical Improvement Project Typical Tasks That Expose Personnel to Underground Power Lines Construction site excavation Jack-hammering Well drilling Landscaping Trenching for piping Fence installation

EFCOG Electrical Improvement Project Excavation Program Elements Designate a Competent Person to oversee all excavation jobs and train to understand the electrical hazard Use written excavation procedure and excavation permit Require an excavation/trenching checklist to be used in job planning Require non-intrusive surveys of areas and develop an interference map of area Ensure excavation planning requirements flow down to subcontractors

EFCOG Electrical Improvement Project Electrical Hazard Identification Perform detailed drawing and map review including original site drawings and recent project drawings Understand that drawings and maps, however, may not be up to date or indicate all field routings correctly Perform walk-down of site surrounding the excavation area and look for conduits and raceways that extend underground and could cross into the excavation work zone Discuss excavation area with facility site knowledge Look for new asphalt, manholes not marked on prints or disturbed soil to identify potential for unmarked interferences

EFCOG Electrical Improvement Project Field Investigation Perform non-intrusive surveys of excavation area using trained and certified utility locators Mark surface with interferences and verify immediately prior to start of excavation Know limitations of non-intrusive equipment –GPR has been off target by 3 feet and may not identify some interferences –Voltage proximity detectors are shielded by ground wire or conduit –Current proximity detectors will not detect if electrical load is turned off

EFCOG Electrical Improvement Project Identifying Interferences De-energize and lockout known electrical hazards-Dont let schedule and convenience take precedent. Hand excavate interferences within excavation limits –Look for different types of soil in the excavation area or for colored concrete that may indicate presence of underground electrical line Consider use of vacuum excavation technology for uncovering interferences Use caution when hand digging-even shovels and post hole diggers can damage direct burial cables

EFCOG Electrical Improvement Project Identifying Interferences Use appropriate PPE (voltage rated gloves and footwear) when identifying electrical interferences –PPE is important since detection of hidden utilities can not always be guaranteed Use double-insulated electrical tools Use fiberglass-insulated shovels and picks when excavating by hand Use rubber mats as appropriate

EFCOG Electrical Improvement Project Other Safe Practices Stop work and call a time out if an unidentified obstruction is found during excavation Revise maps and drawings to reflect actual found field conditions before closing excavation permit Consider use of electronic drill stops when drilling in concrete (DOE Electrical Safety Handbook Section 11) Observe all Power Line Right of Ways and notify power company prior to excavation

EFCOG Electrical Improvement Project Conclusion Remember, you can avoid the pain and suffering that can happen when you contact an underground energized electrical power line Implement and follow the practices in this module Stop work when in doubt