Workplace Safety, ESD Protection and Environmental Practices
Domain 8: Workplace Safety, ESD Protection and Environmental Practices
This section tests electrical safety, soldering hazards, electrostatic discharge control, and responsible disposal. It expects practical controls, not just awareness.
Core rules
- Electrical safety: isolate and lock out before repair, use insulated tools, inspect leads, and respect CAT ratings. Do not work alone on live equipment. Treat capacitors as charged; discharge and prove dead.
- Soldering: use fume extraction, eye protection, and heat-resistant surfaces. Keep flux and solder away from food. Leaded solder requires handwashing; lead-free is not harmless.
- ESD: use a wrist strap with a 1 MΩ series resistor, a grounded mat, and a common ground point. Store ICs in conductive foam or ESD bags. Avoid insulating mats and synthetic clothing in dry conditions.
- Humidity control and ionisers help, but grounding is primary. Do not wear a wrist strap while working on live mains.
- E-waste: segregate batteries, CRTs, PCBs, and plastics; follow local rules. Wipe data-bearing devices before disposal or resale.
Worked example
A technician feels a spark when touching a graphics card in winter. The likely cause is triboelectric charge on clothing and a floating bench. Correct response: power off, use a wrist strap tested at about 1 MΩ to ground, place a grounded mat on the bench, handle the card by edges, and store it in an ESD bag. A 1 MΩ resistor limits current if the wearer contacts live voltage; it does not make live work safe, so the equipment must still be isolated.
Traps
- Believing ESD damage is always immediate; latent damage can pass test and fail later.
- Using a wrist strap without checking its ground connection.
- Wearing a strap while servicing a live power supply.
- Putting lithium batteries in general waste.
- Assuming lead-free solder fumes are safe without extraction.