Electrocution

Welcome back, let’s Build Smart & Build Safe! Electrocution is often referred to as the "invisible killer" because, unlike a trip hazard or a missing guardrail, electricity gives no warning until contact is made. On a construction site, electrical hazards generally stem from three sources: contact with overhead power lines, lack of ground-fault protection, and the use of damaged tools or cords.

Overhead Power Lines: The 10-Foot Rule

Equipment such as cranes, ladders, and scaffolding frequently comes into contact with energized overhead lines. Electricity can "arc" or jump across a gap, meaning you don't even have to touch the wire to be electrocuted.

• Minimum Clearance: Maintain a distance of at least 10 feet from overhead lines rated up to 50 kV. For higher voltages, the clearance distance must increase.

• Non-Conductive Tools: Always use fiberglass ladders when working near electrical installations. Metal or wood ladders (which can hold moisture) can conduct electricity directly to the worker.

• Spotters: If equipment is operating near lines where the operator’s view is obstructed, a dedicated spotter must be used to ensure the 10 feet limit is never breached.

GFCI: Your Primary Defense

A Ground Fault Circuit Interrupter (GFCI) is designed to protect people, not equipment. It monitors the current flowing through a circuit and shuts off the power in as little as 1/40th of a second if it detects a leak.

• Mandatory Use: All 120 V, single-phase, 15-20 amp temporary receptacles must be protected by a GFCI.

• Daily Testing: GFCIs are mechanical and can fail due to dust or moisture. Use the "Test" button daily to verify the internal trip mechanism is functional.

Equipment and Cord Integrity

Relying on a tool with a compromised grounding system is a gamble. Every time a ground pin is removed or a cord is taped over, the risk of a "hot" tool casing increases.

• The Ground Pin: Never use an extension cord or tool with a missing or "clipped" ground prong. The third pin provides the safe path for electricity to follow in the event of a fault.

• Visual Inspections: Check for "strain relief" failures where the cord enters the plug. If the internal colored wires are visible, the cord must be removed from service.

• The "No-Tape" Rule: Electrical tape is for wire splicing inside boxes, not for repairing nicks in extension cords. If the jacket is cut, the cord is a fail.

Implementation: The Site Power Audit

Before plugging in for the day:

1. Look Up: Identify all overhead lines before moving ladders or high-reach equipment.

2. Plug In: Ensure you are plugged into a GFCI-protected source.

3. Inspect: Run your hand (while wearing gloves) down your extension cord to feel for nicks or "bubbles" in the jacket.

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-The Safety Man