Workshop Practice, Tools and Safety
Workshop Practice, Tools and Safety
This domain covers hand and special tools, torque, battery and high-voltage safety, PPE, fire precautions, lifting and housekeeping in an automotive electrical workshop.
Core rules
- Use the right tool: insulated screwdrivers, crimping pliers, terminal picks, torque wrench, pullers, multimeter and insulation tester.
- Torque wrench settings are in N·m; convert with 1 kgf·m ≈ 9.81 N·m. Recalibrate after drops or overloading.
- Lead-acid batteries produce hydrogen, explosive between about 4% and 75% in air. Charge in a ventilated area, with no sparks or naked flames, and remove metal jewellery.
- Battery acid is corrosive: use eye protection, gloves and an acid-resistant apron; neutralise spills with bicarbonate of soda and flush with water.
- Use CO2 or dry-powder extinguishers for electrical fires, never water.
- Support vehicles on stands, chock wheels, disconnect the battery before major electrical work, and observe lock-off procedures.
- Treat hybrid and EV high-voltage systems as live: isolate, verify dead, and use rated PPE and tools.
Worked example
A starter cable carries 180 A and has a resistance of 0.002 Ω. Power dissipated in the cable = I²R = 180² × 0.002 = 64.8 W. That heat must be managed by correct cable gauge and routing away from fuel and insulation. Voltage drop is I × R = 180 × 0.002 = 0.36 V, acceptable but not negligible. A loose terminal adding 0.05 Ω would dissipate 1,620 W at 180 A and could start a fire.
Traps
Wearing rings while working on a battery; charging in a closed area; using water on an electrical fire; trusting a torque wrench that has been dropped; working under a vehicle supported only by a jack; assuming low-voltage vehicle wiring is harmless; failing to label or reconnect harnesses.