Which safety measure can prevent electric shock during maintenance work?

Wearing insulated gloves is a critical safety measure that helps prevent electric shock during maintenance work. These gloves are specifically designed to provide a barrier between the worker's skin and any electrically charged components, thus minimizing the risk of electrical currents passing through the body. Insulated gloves are made from materials that have high dielectric properties, which prevents the conduction of electricity and protects the user when they are performing tasks where they might come into contact with live wires or electrical systems.

The other measures listed may enhance safety in certain contexts but do not directly prevent electric shock to the same degree. For example, while avoiding metal tools can reduce the risk of short circuits or accidental contact with live wires, it does not eliminate the hazard of electric shock if a worker comes into contact with live electrical parts. Using wooden ladders can help in certain scenarios where grounding is a concern, but it doesn’t provide direct protection against electric shock from electrical installations. Conducting routine checks is essential for identifying safety hazards, but it does not offer direct personal protection against electrical contact during maintenance work. Therefore, wearing insulated gloves is the most effective measure to prevent electric shock in this context.