IEC 60990:2016

Overview

IEC 60990:2016 - Methods of measurement of touch current and protective conductor current - specifies standardized measurement methods for d.c. and a.c. currents (sinusoidal and non‑sinusoidal) that could flow through the human body or a protective conductor. The standard defines how to measure currents using networks that represent human‑body impedance and describes test site, instrument, and configuration requirements. It is a Basic Safety Publication intended primarily for technical committees preparing product standards in accordance with IEC Guide 104 and ISO/IEC Guide 51.

Key topics and technical requirements

• Scope and applicability
  • Applies to all classes of equipment per IEC 61140.
  • Not intended for currents of <1 s duration, patient currents (IEC 60601‑1), a.c. below 15 Hz, or currents exceeding electric‑burn thresholds.
• Measurement concepts
  • Use of body‑impedance measuring networks to record touch current; networks model human perception and physiological effects.
  • Separate network weightings for perception / startle‑reaction, let‑go / immobilization, and electric burn effects.
• Test environment and configurations
  • Requirements for test site, transformers/isolation, earthed‑neutral arrangements and power distribution types (TN, TT, IT, centre‑earthed and unearthed delta).
  • Configurations for single‑phase and three‑phase equipment, and for incidental connections.
• Measuring equipment and calibration
  • Instrumentation selection, construction considerations, voltmeter requirements, performance, calibration and confirmation systems (normative and informative annexes).
• Protective conductor current
  • Methods for measuring currents flowing in protective conductors including multiple‑equipment scenarios and evaluation of results.
• Documentation and annexes
  • Normative annexes for equipment, use of a conductive plane, network performance and calibration; informative annexes cover network examples, limitations, grippable-part analysis, and bibliography.

Practical applications and users

• Who uses IEC 60990:2016:
  • Standards and technical committees drafting product‑specific safety standards.
  • Test laboratories and compliance engineers designing and conducting touch‑current and protective‑conductor current tests where specified by product standards.
  • Safety assessors and regulatory bodies when referenced by product standards.
• Typical use cases:
  • Defining measurement procedures for consumer electronics, industrial equipment and appliances where touch current assessment is required.
  • Establishing test configurations for different power distribution systems (TN/TT/IT).
  • Setting up calibration and confirmation systems for touch‑current instruments.

Related standards

• IEC TS 60479 series - provides information on effects of current through the human body (used to derive limit values).
• IEC 61140 - protection against electric shock (equipment classes).
• IEC 60601‑1 - patient safety (patient currents excluded from IEC 60990 scope).
• IEC Guide 104 and ISO/IEC Guide 51 - guidance for preparing safety standards.

Keywords: IEC 60990:2016, touch current, protective conductor current, measurement methods, body impedance network, electrical safety testing.