ELTEK Labs can perform a wide and expanding variety of evaluations on the Electrical Properties of materials for applications across a broad spectrum of industries. Materials are subjected to electrical stresses under a variety of controlled conditions, including liquid contaminants, dust and fog, dry air electrical arc, or high voltage dielectric breakdown conditions.
A sampling of the multitude of tests that we perform, and their related test standards, is presented below.
Surface Tracking
Surface Tracking is the propagation of an electrically conductive path along the surface of an electrical insulator due to the breakdown of the insulation material. Tracking develops from surface discharge activity associated with the flow of leakage current, especially under wet or contaminated conditions. Arcs created from surface discharges burn the insulating material and create electrically conductive carbonized tracks, reducing or eliminating the insulation properties of the material under test.
Tracking Under “Dry” Conditions
ASTM D-495: Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation
IEC 61621: Dry Solid Insulating Materials – Resistance Test to High-Voltage, Low-Current Arc Discharges
UL 746-A: Polymeric Materials – Short Term Property Evaluations:
- Section 22: High-Voltage, Low Current, Dry Arc Resistance Performance Level Categories of Solid Electrical Insulation
- Section 24: High-Voltage Arc-Tracking- Rate Performance level Categories of Solid Insulating Materials
- Section 32: High-Current Arc Ignition Performance Level Categories
- Section 33: High-Current Arc Resistance to Ignition Performance Level Categories
Tracking Under “Wet” or Liquid Contaminant Conditions
ASTM D-2132: Standard Test Method for Dust-and-Fog Tracking and Erosion Resistance of Electrical Insulating Material
ASTM D-2303: Standard Test Method for Liquid-Contaminant, Inclined-Plane Tracking and Erosion of Insulating Materials
- Section 9: Initial Tracking Voltage
- Section 10: Time to Track
IEC 60587: Electrical Insulating Materials Used Under Severe Ambient Conditions – Test Methods for Evaluating Resistance to Tracking and Erosion
UL 746-A: Polymeric Materials – Short Term Property Evaluations
- Section 25: Liquid Contaminant, Inclined- Plane Tracking, and Erosion of Insulating Materials
ASTM D-3638: Standard Test Method for Comparative Tracking Index of Electrical Insulating Materials
IEC 60112: Method for the determination of the proof and the comparative tracking indices of solid insulating materials
UL 746-A: Polymeric Materials – Short Term Property Evaluations
- Section 23: Comparative Tracking Index and Comparative Tracking performance Level Category of Electrical Insulation Materials
Dielectric Strength
Dielectric Strength is the maximum electric field strength that an insulating material (a ‘dielectric’) can withstand without experiencing a failure of its insulation properties (‘breakdown’). The dielectric strength of a material is dependent on the configuration of the material and the electrodes with which the field is applied. Other factors such as temperature, frequency of the electric field, rate of increase of the electric field (rate of rise), or material thickness, may also impact dielectric strength.
ASTM D-149: Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
IEC 60243: Electrical strength of insulating materials – Test methods
- Part 1: Test at power frequencies
- Part 2: Additional requirements for tests using direct voltage
UL 746-A: Polymeric Materials – Short Term Property Evaluations: Section 20: Dielectric Breakdown Voltage and Strength
ASTM D-877: Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disc Electrodes
ASTM D-120: Standard Specification for Rubber Insulating Gloves
- Section 11: Electrical Requirements
- Section 18: Electrical Tests
ASTM D-178: Standard specification for Rubber Insulating Matting
- Section 11: Electrical Requirements
- Section 18: Electrical Tests
Corona Discharge
A Corona Discharge is an electrical discharge brought about by the ionization of a fluid surrounding a conductor that is electrically energized. The discharge will occur when the strength of the electric field around the conductor is high enough to form a conductive region, but not high enough to cause dielectric breakdown or an arc discharge to nearby objects.
IEC 60343: Recommended test methods for determining the relative resistance of insulating materials to breakdown by surface discharges
Surface and Volume Resistivity
Resistivity describes how strongly a material opposes the flow of electrical current. A low resistivity indicates that a material readily allows the movement of electrical charge. Resistivity is the reciprocal of conductivity, so a material with low resistivity has high conductivity.
The total electrical resistance of an insulation material is broken into two parts: the resistance along the surface of the material and the resistance through the volume of the material.
Surface resistivity measures the ratio of the DC voltage applied to two electrodes on the surface of a specimen to the current between them. Surface resistivity is expressed in ohms (Ω).
Volume resistivity measures the ratio of the DC voltage applied to two electrodes on or in a specimen to the current in the volume of the specimen between them. Volume resistivity is expressed in ohm-centimeters (Ω-cm).
ASTM D-257: Standard Test Methods for DC Resistance or Conductance of Insulating Materials
- Section 12.1: Insulation Resistance or Conductance
- Section 12.2: Volume Resistivity or Conductivity
- Section 12.3: Surface Resistance or Conductance
IEC 60093: Methods of test for volume resistivity and surface resistivity of solid electrical insulating materials
IEC 60167: Methods of test for the determination of the insulation resistance of solid insulating materials
UL 746-A: Polymeric Materials – Short Term Property Evaluations
- Section 21: DC Resistance or Conductance of Insulating Materials
To arrange electrical properties testing, request a quote online or call 636-949-5835.
