CSLB C-46 Solar ContractorSafetyMedium
A solar crew is installing modules on a residential roof. They need to access the roof using a portable ladder. What is the MINIMUM safe angle at which the base of the ladder should be placed relative to the wall?
- A75 degrees
- B70 degrees
- C60 degrees
- D80 degrees
Show answer & explanationAnswer & explanation
Correct answer: A. 75 degrees
The '4 to 1 rule' or '75-degree angle' is the standard for safe ladder placement. For every 4 feet of vertical height, the base of the ladder should be 1 foot away from the wall.
Why the other options are wrong
- B. A 70-degree angle is still too shallow and increases the risk of the ladder sliding out.
- C. A 60-degree angle would place the ladder too far from the wall, making it unstable and prone to slipping.
- D. An 80-degree angle would place the ladder too close to the wall, increasing the risk of tipping backward.
Ladder 4 to 1 Rule
For safe ladder setup, the base of the ladder should be placed 1 foot away from the wall for every 4 feet of vertical height to the point of support, resulting in approximately a 75-degree angle.
- Ensures stability and reduces slipping/tipping.
- Applies to portable extension and straight ladders.
- Always ensure proper footing and tie-off if possible.
Memory trick: Four up, one out, keeps the ladder safe, no doubt!