Under which circumstance must a MEWP's slope warning device activate?

A Mobile Elevating Work Platform (MEWP) is designed to operate safely under specific conditions, and the slope warning device plays a crucial role in maintaining that safety. When the base of a MEWP is off level by a specific angle, the slope warning device activates to alert the operator that the platform may be operating in an unsafe condition. This is critical because operating a MEWP on uneven ground can lead to instability, increasing the risk of tipping or accidents.

Maintaining an appropriate level position is essential for the safe operation of a MEWP, as an unlevel base can compromise the structure’s integrity and the safety of personnel working on the platform. Therefore, the activation of the slope warning device under these conditions is a key safety feature that ensures operators are made aware of potential hazards.

Other circumstances, such as when the MEWP is fully loaded or when the control is engaged, do not necessarily trigger the slope warning device because they do not directly correlate with the stability and safety of the MEWP's operation. Moreover, exceeding operating speed is more related to operational safety than to the warning mechanisms related to the slope of the vehicle. Thus, the correct answer is focused on ensuring operational safety through awareness of the platform's stability.