CPCS Excavator Operations — Questions and Answers
Question 1: When positioning a tracked excavator on a slope, which direction should the tracks face for maximum stability?
- Perpendicular to the slope
- Parallel to the slope with the drive sprockets uphill (Correct answer)
- At a 45-degree angle to the slope
- It does not matter as long as the outriggers are deployed
Correct answer: Parallel to the slope with the drive sprockets uphill
When working on a slope, the tracks should run up and down the slope (parallel) with the drive sprockets positioned uphill. This provides maximum ground contact and stability, and if the machine begins to slide, the operator has more control.
Question 2: What is the correct procedure before slewing an excavator with a loaded bucket?
- Sound the horn and slew immediately
- Check the swing area is clear of personnel and obstructions (Correct answer)
- Raise the boom to maximum height then slew
- Lower the bucket to ground level then slew
Correct answer: Check the swing area is clear of personnel and obstructions
Before slewing, the operator must visually check that the swing radius is clear of all personnel, vehicles, and obstructions. The slewing motion of an excavator is one of the most common causes of struck-by incidents on construction sites.
Question 3: What does the term 'working radius' mean in relation to an excavator?
- The maximum distance the machine can travel in one shift
- The horizontal distance from the centre of rotation to the bucket edge (Correct answer)
- The total area of the construction site
- The distance between the tracks
Correct answer: The horizontal distance from the centre of rotation to the bucket edge
The working radius is the horizontal distance measured from the centre of the machine's slew ring to the cutting edge of the bucket. It determines the machine's reach and is critical for planning excavation work and maintaining safe distances from hazards.
Question 4: When excavating near underground services, what is the safe hand-digging distance from the indicated line of the service?
- 300mm either side
- 500mm either side (Correct answer)
- 1 metre either side
- 2 metres either side
Correct answer: 500mm either side
HSE guidance (HSG47) recommends that within 500mm either side of the indicated line of an underground service, excavation should be carried out by hand using insulated tools. This prevents accidental damage to cables, gas pipes, or water mains.
Question 5: What should an excavator operator do if they strike an underground cable during digging?
- Continue digging carefully around it
- Stop work immediately, move everyone away, and report it (Correct answer)
- Try to repair the cable themselves
- Cover it back up and move to a different area
Correct answer: Stop work immediately, move everyone away, and report it
If an underground cable is struck, the operator must stop work immediately, keep everyone well clear, and report the incident to the site supervisor and the utility company. A damaged electrical cable can be lethal even if it appears undamaged.
Question 6: What is the purpose of the quick hitch (quick coupler) on an excavator?
- To increase the machine's digging depth
- To allow rapid attachment changes without leaving the cab (Correct answer)
- To improve the fuel efficiency of the machine
- To connect the machine to a trailer for transport
Correct answer: To allow rapid attachment changes without leaving the cab
A quick hitch allows the operator to change between different attachments (buckets, breakers, grabs) quickly and safely from the cab. However, it must be properly maintained and checked, as quick hitch failures have caused fatal accidents.
CPCS Excavator Operations
When positioning a tracked excavator on a slope, which direction should the tracks face for maximum stability?