UL Standard for Safety Requirements for Electrical Equipment for Measurement@ Control and Laboratory Use – Part 2-032: Particular Requirements for Hand-Held and Hand-Manipulated Current Sensors for Electrical Test and Measurement (First Edition)
This part of IEC 61010 specifies safety requirements for HAND-HELD and hand-manipulated current sensors described below. These current sensors are for measuring@ detecting or injecting current@ or indicating current waveforms on circuits without physically opening the current path of the circuit being measured. They may be stand-alone current sensors or accessories to other equipment or parts of combined equipment (see Figure 101). These include measurement circuits which are part of electrical test and measurement equipment@ laboratory equipment@ or process control equipment. The existence of these current sensors and circuits in equipment requires additional protective means between the current sensor@ the circuit and an OPERATOR. NOTE 1 This part includes also the requirements of Part 2-030. Testing and measuring circuits that are not within the scope of this part are considered to be covered by the requirements of Part 1 or other parts 2s of IEC 61010@ and then will also need to meet the requirements of these other parts with the exception of Part 2-030. Current clamp meters and similar currents sensors that have a primary purpose of measuring voltage on a live MAINS CIRCUIT are also within the scope of Part 2-033. NOTE 2 Some current sensors are also known as current clamps and current probes. Current sensors require hand manipulation before or after a test or measurement@ but do not necessarily need to be HAND-HELD during the test or measurement. NOTE 3 Some current sensors designed for portable use can also be used for fixed installations. The following types of current sensors are covered: a) Type A: a current sensor designed to be applied around or removed from UNINSULATED HAZARDOUS LIVE conductors. Type A current sensors have defined HAND-HELD or hand-anipulated parts providing protection against electric shock from the conductor being measured@ and also have protection against short-circuits between wires and busbars during clamping. b) Type B: a current sensor which has protection against short-circuits between wires or busbars during clamping but without defined HAND-HELD or hand-manipulated parts which provide protection against electric shock during clamping. Additional protective means are necessary to avoid electric shock from HAZARDOUS LIVE conductors which cannot be de-nergised during application or removal of the current sensor. EXAMPLE 1 Flexible current sensors. c) Type C: a current sensor without protection against short-circuits between wires or busbars during clamping. Type C current sensors are intended to be applied to or removed from UNINSULATED HAZARDOUS LIVE conductors or from non-limited-energy circuit conductors only when they are de-energised. EXAMPLE 2 Split-core transducers. d) Type D: a current sensor designed to be applied around or removed from insulated conductors or from limited-energy circuit conductors. A Type D current sensor does not need protection against short-circuits during clamping and has no defined HAND-HELD or hand-manipulated parts providing protection against electric shock from the conductor being measured. EXAMPLE 3 Current probes for oscilloscopes and earth leakage current detectors. NOTE 4 All current sensors can also be used around insulated conductors. In this case@ HAZARDS are limited to acceptable levels by the insulation of the conductors.