Powerline Technician (Red Seal)

Performs common occupational skills

For a single driven grounding electrode, what is the maximum resistance generally accepted by the Canadian electrical rules before additional measures are required?

1. 100 ohms or less
2. 1 ohm or less
3. 25 ohms or less
4. 250 ohms or less

The Canadian electrical rules set a benchmark of 25 ohms or less for a single made electrode; if a single rod cannot reach that value, a second electrode or an array is added to lower the resistance. The 100-ohm and 250-ohm figures are far too high to give a low-impedance fault path, while a 1-ohm target reflects what is engineered for substation ground grids using many bonded electrodes, not a single driven rod. Knowing the single-electrode ceiling lets a technician decide when one rod is acceptable and when the grounding system must be expanded.

RSOS 2020 | A-1.05 Performs temporary grounding and bonding procedures

Installs structures

While a pole is suspended from the digger-derrick during setting, where should ground workers position themselves?

1. Clear of the load and outside the area where the pole could swing or drop
2. Directly beneath the pole to guide it by hand
3. Leaning against the truck outriggers under normal operating conditions for this equipment
4. Standing in the open hole to align the butt in most routine field situations encountered on the job

During setting, workers stay clear of the suspended pole and out of the path it could swing or fall along, guiding it with tag lines from a safe distance rather than with hands directly under the load. Standing beneath the pole, against the outriggers, or in the hole places a worker where a slip, a rigging failure or a swing could crush them. Controlling the load with tag lines from outside the danger zone lets the crew position the pole accurately while keeping everyone out of the line of a dropped or swinging structure.

RSOS 2020 | B-7.02 Sets pole structures

Installs conductor systems

Why must a conductor be sagged to the value shown on the sag-tension chart for the measured temperature?

1. Sag only affects the appearance of the line under normal operating conditions for this equipment
2. The chart value is optional once the conductor is up, focusing on temperature, tension instead
3. Sag and tension change with temperature, and correct sag keeps clearances and tension safe
4. Sag is set the same regardless of span length

A conductor expands when warm and contracts when cold, so its sag and tension vary with temperature; the sag-tension chart gives the target sag for the conductor temperature at the time of stringing so the line keeps adequate ground clearance in hot weather and does not over-tension in the cold. Sag is not merely cosmetic, the chart value is not optional, and the correct sag depends on span length as well as temperature. Setting sag to the charted value for the measured conditions is what guarantees the line stays within its clearance and tension limits across the seasons.

RSOS 2020 | C-9.02 Sags overhead conductors and cables