Workbench Skills Part 3: Measure mains voltage safely
AC volts, a CAT II / CAT III meter, never in the amps socket; 230 V · 50 Hz (India, UK, Europe), 120 V · 60 Hz (USA, Canada).
Wrong socket? BANG! 💥 Here's how to measure mains voltage the safe way 👇
⚠️ Only measure mains if you're trained. If not, practise on batteries first!
1️⃣ THE DIAL: turn it to V with a wavy line (V~) = AC volts.
2️⃣ THE SOCKETS: black lead in COM, red lead in V (VΩ). NEVER the 10 A socket — it's for current only and is almost a short circuit. Touching mains with a lead in it can blow up.
3️⃣ THE RATING: use a meter rated CAT II or CAT III (printed next to the sockets). CAT II = sockets and plug-in appliances, CAT III = home wiring and panels.
4️⃣ YOUR HANDS: keep your fingers behind the finger guards on the probes.
You'll read about 230 V · 50 Hz (India, UK, Europe) or 120 V · 60 Hz (USA, Canada).
Dial, socket, rating!
Read the voiceover (transcript)
- Wrong socket? Bang! Do it safely.
- Dial to V with a wavy line: AC volts. Black in COM, red in V.
- Never the ten amp socket! Use a CAT two or CAT three meter.
- Fingers behind the guards. Mains reads about two-thirty volts, or one-twenty in the US.
- Dial, socket, rating!
- Next: the continuity beep! Follow for part four!
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