A plumber is required to enter a trench that is 1.8 metres deep to repair a broken sewer line. The soil appears to be Type A and there are no signs of previous disturbance. What is the minimum protective system that must be in place before entry, according to standard safety regulations?

Question: A plumber is required to enter a trench that is 1.8 metres deep to repair a broken sewer line. The soil appears to be Type A and there are no signs of previous disturbance. What is the minimum protective system that must be in place before entry, according to standard safety regulations?

Answer options: ✅ A trench box or shoring system designed by a competent person.

• Sloping the trench walls to a 1:1 ratio (45 degrees).
• A ladder for egress and a spotter at the surface.
• No protective system is strictly required if the soil is Type A and undisturbed.

Correct answer: A trench box or shoring system designed by a competent person.

Explanation: For trenches 1.2 metres (4 feet) or deeper, a protective system like a trench box or shoring is generally required, regardless of soil type, to prevent cave-ins. Even Type A soil can collapse unexpectedly. Sloping alone might not be sufficient or practical in all situations, and a ladder/spotter are additional safety measures, not primary protective systems against collapse.