Safety Focus of the Week: Working Around Overhead Electrical Lines – Revisited
I remember working in a hydro power plant years ago where the open bus work was only about 2 feet from a pedestrian walkway. The only protection for a worker in the plant was a handrail. A sign on the rail stated: “High Voltage – Danger of Death”, a pretty blunt and accurate message that gets right to the point.
Whenever we work around power at ECI, we need to identify the risk and have a plan in the tailboard to eliminate that risk. The OSHA Construction Standard (Part CC) includes separate minimum clearances for cranes and the Mechanized Equipment Standard (Part O) is for all other equipment (excavators, concrete pumper booms, loaders, etc). The Crane Standard minimum clearance chart is easier to use since it does not involve a calculation to compute the minimum clearance:
(nominal, kV, alternating current)
|Minimum clearance distance
|up to 50
over 50 to 200
over 200 to 350
over 350 to 500
over 500 to 750
over 750 to 1,000
45(as established by the utility owner/operator or registered professional engineer who is a qualified person with respect to electrical power transmission and distribution).
Reference: OSHA Construction Standard 1926.1408 (H)
In addition to recognizing the hazard, the daily tailboard should include provisions to prevent violating these clearances, as considered in the Crane Standard. Such provisions might include: a dedicated spotter with direct communication to the operator, marking delineation, or barriers to prevent operations from entering into a restricted zone. Other helpful measures include: “High Voltage Overhead” signage and protective covers on the conductors (installed by power company).