Which two items must be used to stabilize a mobile scaffold?

The correct answer highlights the importance of using specific components that enhance the stability and safety of mobile scaffolds. Outrigger braces are critical as they extend the base's support beyond the standard footprint of the scaffold, effectively distributing the weight and preventing tipping. Buttress sections add further support and ensure that the scaffold remains upright, especially when extending it to greater heights or when subjected to lateral loads or wind forces.

In mobile scaffolding, it is essential to ensure stability during both usage and when moving the scaffold. Outriggers and buttresses are designed to meet these stability needs, making them integral parts of a safely erected mobile scaffold.

The other options do provide equipment related to scaffold safety, but they do not specifically address the stabilization aspect effectively. Safety harnesses are for personal fall protection, not for stabilizing the scaffold itself. Ramps and wheel locks aid in accessibility and preventing movement, but they do not provide the structural stability needed during use. Cross braces and guardrails are vital components for safety and preventing falls, but they do not offer the same stabilizing function as outrigger braces and buttresses do.