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title: "Electrical Safety Construction Sites Hazards | AVANORTH"
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description: "Electrical safety guide for construction: overhead power lines, GFCI protection, lockout/tagout procedures, and common hazard prevention."
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"og:title": "Electrical Safety Construction Sites Hazards"
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AVANORTH Home
**Safety**·April 7, 2026· 4 min read
# **Electrical Safety on Construction Sites: Preventing Hazards**
Electrocution is one of the top causes of construction fatalities. Understanding electrical hazards, safe work practices around power lines, GFCI protection, and lockout/tagout procedures saves lives on every project.
**AVANORTH Team**
AVANORTH Construction
Electrocution is consistently among the top four causes of construction worker fatalities (the "Fatal Four" along with falls, struck-by, and caught-in/between). On construction sites, electrical hazards come from two primary sources: contact with overhead or underground power lines, and improper use of temporary electrical systems. Both are preventable with proper planning and safe work procedures.
---
## Common Electrical Hazards on Construction Sites
| Hazard | Source | Risk |
| --- | --- | --- |
| Overhead power lines | Existing utility lines near/over the site | Crane, boom, or equipment contact = electrocution |
| Underground utilities | Buried cables, gas lines | Excavation damage = electrocution, explosion |
| Temporary wiring | Extension cords, temp panels, spider boxes | Damaged cords, overloaded circuits, no GFCI |
| Power tools | Drills, saws, grinders | Damaged cords, missing ground pin, wet conditions |
| Energized systems | Electrical panels, switchgear being installed | Contact during installation or testing |
| Lightning | Open site, tall equipment (cranes) | Direct strike or ground current |
---
## Overhead Power Line Safety
Contact with overhead power lines is one of the most common causes of multiple-fatality electrical incidents in construction. The voltages are extremely high (typically 4,800V to 500,000V on transmission lines), and the current available is essentially unlimited.
### Ontario Minimum Approach Distances
| Voltage (Line to Line) | Minimum Distance |
| --- | --- |
| 750V to 150,000V | 3 metres (10 ft) |
| 150,001V to 250,000V | 4.5 metres (15 ft) |
| Over 250,000V | 6 metres (20 ft) |
> **Critical Understanding:** These are minimum distances from any part of any equipment, load, or rigging to the nearest power line. For cranes, this means the tip of the boom, the load block, the hoist line, AND the load must all maintain the minimum distance at all times. Electricity can arc across gaps, especially at high voltage. The minimum distance includes an air gap safety factor, but it is not a target to aim for. Stay as far away as possible.
### Protective Measures
- **Contact the utility:** Before any work near overhead lines, contact the local utility (Ontario One Call for locates, direct contact with the utility for power line protection)
- **De-energize:** The safest approach is to have the utility de-energize the line. If de-energization is not possible, request protective measures (insulating guards).
- **Signalman:** A dedicated signalman whose only job is maintaining safe clearance between equipment and power lines
- **Physical barriers:** Warning posts, flagging, and barrier tape at the limit of approach
- **Equipment restrictions:** Restrict crane swing, boom angle, and travel to prevent encroachment into the danger zone
---
## Ground Fault Circuit Interrupter (GFCI) Protection
A GFCI monitors the current flowing in the hot and neutral conductors. If there is a difference (meaning current is flowing through an unintended path, such as through a worker's body), the GFCI trips within milliseconds.
### When GFCI Is Required
- All 15A and 20A, 120V receptacle outlets on construction sites
- All temporary wiring installations
- All extension cords used outdoors or in wet/damp locations
- The GFCI must be at the source (panel, spider box) or an in-line GFCI device
### GFCI Testing
1. Test every GFCI device before each use (daily minimum)
2. Press the "test" button: the device must trip (power cuts off)
3. Press the "reset" button: power must restore
4. If the device does not trip when tested, remove it from service immediately
---
## Lockout/Tagout (LOTO)
Before any work on electrical equipment, the energy source must be isolated. Lockout/tagout ensures that the equipment cannot be accidentally re-energized while someone is working on it.
| Step | Action | Purpose |
| --- | --- | --- |
| 1. Notify | Inform all affected workers | Everyone knows the system is being de-energized |
| 2. Identify | Identify all energy sources | Electrical may have multiple feeds, backup power |
| 3. Isolate | Open disconnects, breakers at all sources | Physically interrupt the energy supply |
| 4. Lock | Apply personal lock to each isolation point | Prevent re-energization (each worker applies their own lock) |
| 5. Tag | Apply tag with name, date, reason | Communicate who locked out and why |
| 6. Verify | Test for zero energy (voltage tester) | Confirm the system is truly de-energized |
| 7. Work | Perform the work | Safe to work on de-energized equipment |
| 8. Restore | Remove locks/tags, close disconnects, notify | Each worker removes only their own lock |
> **AVANORTH Policy:** Every toolbox talk at the start of electrical rough-in includes a review of LOTO procedures. Every worker performing electrical work carries their own lock. No one removes another worker's lock. We verify zero energy with a properly rated voltage tester before any contact with conductors. There are no exceptions.
#electrical-safety #GFCI #lockout-tagout
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