Test Instruments & Measurement

Choosing instruments, using them safely, and knowing where each one misleads. Measurement category is a safety rating rather than an accuracy one, and the two commonest field errors — averaging meters on distorted waveforms, and ghost voltages on high-impedance inputs — both produce confident, entirely believable wrong numbers.

Scope

• ▪Measurement categories and instrument selection
• ▪True-RMS versus averaging on distorted waveforms
• ▪Ghost voltages and low-impedance mode
• ▪AC versus DC clamp measurement
• ▪Insulation testing and protecting electronics
• ▪Interpreting readings in context

Diagnosis guides

• Test Instruments and the Measurement Errors That Mislead You

  Multimeters, clamp meters, insulation testers, voltage indicators and thermal cameras used on generators, UPS systems, inverters, drives and installations

  8 diagnostic steps · intermediate · qualified electrician