How close a boom truck may work to a power line

R 03 mWhy the boom, not the truck, is the hazard

A boom truck can park well clear of a line and still put its boom tip, hook or load inside the limit of approach once it swings, extends or booms up.

Three things shrink the real gap:

• The boom deflects. IHSA notes that radius grows under load as the boom and machine deflect¹, so the tip moves toward the line on the pick.
• The load swings. Plan to the nearest point the load could reach, not where it hangs at rest.
• The line moves. Conductors sag and sway. Measure from the nearest conductor and leave room.

Every table is keyed to voltage, and you cannot read voltage off a pole. Alberta makes finding it the employer's duty within 7 m of a line². Ask the line's owner.

Before the truck arrives

1. Mark every overhead line the boom could reach, in every direction it might swing.
2. Get each line's voltage from its owner, in writing where you can.
3. Look up the distance with the power-line lookup.
4. Choose a set-up position where the boom cannot reach that distance, or agree with the owner what happens instead.
5. Put the line on the quote request: the supplier plans the truck and its position.

R 06 mThe distances side by side

Each jurisdiction's bands, as its regulation writes them. Voltages are phase to phase.

Three example voltages, read from the bands above:

Two reading rules. At a band boundary, use the larger distance. A voltage between bands has no distance in these rows: Alberta and Yukon list nothing between 40 kV and 69 kV, Saskatchewan and Nunavut nothing between 25 kV and 72 kV. Get those distances in writing from the line's owner; the lookup deliberately shows no number.

R 09 mAlberta: the 7 m trigger and Schedule 4

Alberta's rule starts at 7 m: within 7 metres of an overhead line, the employer must determine its voltage, set the limit of approach from Schedule 4² and keep all work and equipment at least that far away².

Below 750 V, Schedule 4 allows 300 mm for insulated or polyethylene-covered conductors and 1.0 m for bare ones², but only when they are covered along their entire length².

Working closer. Before any work goes inside the Schedule 4 distance, the employer must notify the line's operator and get its help protecting the workers².

Two rules that catch sites out. Earth and other materials must not be placed where they would cut the clearance below the limit, and every worker has a personal duty to keep the distance². The s.227 exemption covers only utility workers working to CAN/ULC-S801-14². More in boom truck and picker rules in Alberta.

R 12 mBritish Columbia: written assurances and safety watchers

WorkSafeBC's Table 19-1A has three bands, from 3 m (10 ft) over 750 V³ to 6 m (20 ft) over 250 kV³, phase to phase. Part 14 applies it to the crane, its rigging and its load¹⁵.

When the distance cannot be kept, BC asks for paper and people. A written assurance from the owner of the power system is required, and where the lines cannot be isolated, rerouted or guarded, the area must be barricaded and a safety watcher with a positive stop signal designated³. The operator must stop on a stop signal from anyone¹⁵.

BC's critical lifts include, beside a lift over 90% of rated capacity at more than half the maximum radius, any lift over or between energized high-voltage conductors¹⁵. That brings a written lift plan and a documented pre-job meeting¹⁵; see planning a boom truck lift.

Table 19-1A starts above 750 V; for lower voltages, ask the owner. More in boom trucks and crane trucks in British Columbia.

R 15 mOntario: written procedures and a signaller

Ontario's construction regulation keeps every object at least 3 m from an energized overhead conductor of 750 V up to 150,000 V⁶, rising to 6 m above 250,000 V⁶.

The first band is wide: a 138 kV line needs 3 m in Ontario where Alberta asks 4.0 m⁶².

Where a crane could encroach on the distance, two more rules apply:

• Written measures and procedures. The constructor sets them, including warning devices, written notice to the operator and a sign at the operator's station⁶.
• A designated signaller. A competent worker is stationed in full view of the operator, with a clear view of the conductor, and warns each time the equipment or load may approach the minimum distance⁶.

The signaller watches the line while the operator watches the load. On an industrial establishment, Regulation 851 keeps the same three distances¹⁶ and stations a worker to warn the operator¹⁶. More in boom trucks in Ontario.

R 18 mSaskatchewan, Manitoba and the territories

Saskatchewan. Table 19, column 1, covers non-electrical workers, material and equipment, from 3 m at 0.75 kV⁴ to 6.1 m at 230 kV⁴. A line between 25 kV and 72 kV needs its distance in writing from the owner.

Manitoba. Part 25 works differently. It applies when work or equipment can come within 3 m of an overhead line: the employer must notify the electrical authority, get written confirmation or instructions and, when instructed, assign a signal person with an unobstructed view of the operator⁵. Treat 3 m as the point where the call is required, not as a safe distance.

Northwest Territories. Schedule Y, column 3, has the same values as Saskatchewan's Table 19, from 3 m up to 25 kV to 6.1 m at 230 kV¹².

Yukon. Table 9-1 gives 3.0 m from 750 V to 40 kV, rising to 7.0 m at 500 kV, and 7.0 m applies where the voltage has not been determined¹³. If the distance cannot be kept, a written assurance signed for the utility is required¹³. Yukon Energy's own sheet gives 3 m up to 40,000 V and 4 m at 138,000 V¹⁷, so ask the utility which applies. We read the WCB's online copy of the regulation, which says it is not the official text.

Nunavut. Its own regulation, Schedule Y, column 3, lists seven single voltages: 3 m at 0.75, 4.16, 15 and 25 kV, 4.6 m at 72 and 138 kV, 6.1 m at 230 kV, the same as the NWT's¹⁴. At 31 to 750 V the employer must prevent accidental contact, and no distance is tabled¹⁴.

R 21 mQuebec

Quebec's construction safety code has the widest spread of distances we found: any part, load or machinery must stay 3 m from a line under 125,000 V⁷, and 12 m above 550,000 V⁷.

Work inside those distances is allowed in three cases only⁷:

• the line is de-energized;
• an agreement with the utility has been sent to the CNESST; or
• extendable equipment carries a dual-function range-limiting device certified by an engineer, and a trained operator runs it.

The code covers construction; Quebec's rules outside construction were not checked. More in boom trucks in Quebec.

R 24 mAtlantic Canada, and driving under lines

New Brunswick and Prince Edward Island use the same four distances, from 900 mm (up to 750 V) to 6.1 m (250 to 345 kV); New Brunswick applies them to non-qualified workers and to objects⁸. Above 345 kV, PEI requires the utility's instructions first¹⁰.

Newfoundland and Labrador sets 3 m to 6 m by voltage¹¹, and adds paper: before a mobile crane or boom truck works near conductors, the employer must get the voltage and clearance in writing from the utility, or keep 5.5 m¹¹. Operators of equipment that could encroach on a line must first complete a power line hazards training program¹¹.

Nova Scotia keeps its limits in the Occupational Safety General Regulations, s.126, because Part 15 of its newer health and safety regulations is an empty placeholder¹⁸. Before work could come closer than the distance, the employer contacts the utility⁹, and a competent signaller is needed where the operator cannot see the distance or the hoist is closer than its boom length to the line⁹.

Driving under lines

Four jurisdictions treat travel separately from lifting:

• Alberta does not apply Schedule 4 to a load or equipment transported under a line when the total height, carrier included, is under 4.15 m².
• British Columbia sets passing distances for equipment only moving under exposed conductors: 2 m (over 750 V to 75 kV) to 4 m (250 to 550 kV)³.
• Saskatchewan keeps vehicles and their loads on public roads at least 0.6 m (25 kV and below) to 1.83 m (230 kV) from exposed energized conductors⁴.
• Nunavut sets the same 0.6 m to 1.83 m for vehicles and loads on public roads, with 0.8 m at 72 kV and 1.22 m at 138 kV¹⁴.

Elsewhere our research found no travel distance, including Yukon, so assume the operating distance applies unless the regulation says otherwise. Know the truck's travel height with the boom stowed.