Workshop safety, tools and equipment
Workshop safety, tools and equipment
The CHSE vocational paper checks whether you can set up a bay, select and care for hand and power tools, and control the hazards that actually occur in Indian workshops: vehicle falls, battery gas, fuel vapour, exhaust CO, high-voltage EV cables and rotating parts.
Core rules
- Chock wheels and use rated jack stands before going under a vehicle. A hydraulic jack is a lifting device, not a support.
- Disconnect the battery negative first and reconnect it last; wait the manufacturer's specified time, often 1–3 min, before touching airbag circuits.
- Store fuel in approved metal containers, bond containers when decanting, and keep ignition sources away. Petrol vapour is heavier than air.
- Use a calibrated torque wrench within its 20–100% range; release tension after use. For a micrometer, check zero, use the ratchet thimble and measure at three points.
- Use pullers, not hammers, for bearings and ball joints; wear eye protection when using a chisel or grinder.
- EV and hybrid orange cables: isolate, verify dead with a CAT III meter, and use insulated tools.
Worked example
A wheel nut is specified 110 N·m. Your wrench is 0.3 m long. Minimum hand force at the handle = 110/0.3 = 367 N, about 37 kgf, applied steadily at 90° to the handle. If you use a 0.5 m breaker bar to loosen, you apply far more torque than the fastener needs; use it only for loosening, then torque with the wrench.
Traps
- Using a jack alone under a car.
- Setting torque by feel, or torqueing a dirty, lubricated thread to a dry specification.
- Assuming a red cable is always live, or that a low-voltage test lamp is safe on HV.
- Leaving the wrench set at maximum tension, which drifts calibration.