Why should all electrical switches be in the OFF position prior to starting an MWS apparatus?

The need to have all electrical switches in the OFF position prior to starting a Mobile Water Supply (MWS) apparatus is primarily to prevent the engine from starting under load. When electrical devices or systems are engaged while attempting to start the engine, they can draw power from the battery and create an additional load on the engine. This situation can lead to difficulty in starting the engine, potential damage to the electrical components, or overpowering the starter motor.

By ensuring all switches are turned OFF, you allow the engine to start efficiently without any competing electrical demands, thereby safeguarding the vehicle's electrical system and ensuring a smoother and more reliable startup process. This practice helps maintain the integrity of the apparatus's systems and enhances operational readiness.