7.1 Current and the body

I declare: solidlikelyshaky

1. Give the thresholds of current through the body (perception, tetanization, fibrillation) and explain why it’s current that kills, not voltage.
2. Explain why low voltage protects (skin resistance) and where the 48 to 60 V DC frontier sits.
3. Say what makes the mains dangerous even at 120 V, and what a ground-fault interrupter detects.
4. Explain appliance grounding and double insulation (the square inside the square on the label), and what each protects.
5. Diagnosis: a small shock touching an appliance, leakage, missing ground or line-neutral reversed; how to measure it without putting yourself in danger.