The resistance of the conductive shoes was measured after being conditioned in both dry and humid environments to evaluate their performance under different conditions. This ensures that the shoes meet safety standards for use in various settings.

Test Instrument
A DC voltage of (100 ± 2) V is applied during the test, allowing for a measurement accuracy of ±2.5%. This precision ensures reliable results for assessing the electrical properties of the shoes.

Internal Electrode
The internal electrode consists of stainless steel balls with a total mass of 4 kg and a diameter of 5 mm. To maintain conductivity, measures must be taken to prevent or remove oxidation from the steel balls and copper plates, as oxidation can significantly affect electrical performance.

External Electrode
The external electrode is made up of a copper contact plate that is cleaned with ethanol before each use to ensure proper contact and accurate readings.

Device for Measuring Conductive Coating Resistance
This device includes three conductive metal probes, each with a radius of (3 ± 0.2) mm, mounted on a base plate. Two of the probes are spaced (45 ± 2) mm apart and connected by a metal strip. The third probe is positioned (180 ± 5) mm from the midpoint of the other two and is insulated from them to avoid interference.

Sample Preparation
If the shoe has an activity mat, it should remain in place during testing. The sole surface should be cleaned with alcohol to remove any release agents, followed by rinsing with distilled water. After cleaning, the sample should be dried at (23 ± 2)°C. It is important not to rub or wear the sole, and no organic solvents should be used that could damage or expand the material.

Special Preparation for Wet Conditioning
For specimens tested under wet conditions, a conductive coating measuring 200 mm x 50 mm is applied to the sole, covering both the heel and forefoot areas. The coating must have a resistance value of less than 1 x 10³ megohms. The shoe is then filled with clean steel balls and placed on the device’s metal probes so that the forefoot is supported by two probes 45 mm apart, while the heel is supported by the third probe. The resistance between the third probe and the others is measured using the test instrument.

Depending on the intended function of the shoe, the prepared sample should be adjusted according to one of the following conditions:

1) Dry Conditions: (20 ± 2)°C, relative humidity (30 ± 5%) – left to condition for 7 days.

2) Wet Conditions: (20 ± 2)°C, relative humidity (85 ± 5%) – left to condition for 7 days.

If testing cannot be conducted in a controlled environment, it must be completed within 5 minutes after removing the sample from the conditioning chamber.

Test Procedure
Fill the shoe with clean steel balls totaling 4 kg. If necessary, use insulating material to raise the upper part of the shoe. Place the filled shoe on a copper plate and apply a (100 ± 2) V DC test voltage between the steel ball and the copper plate for 1 minute. Record the resistance value obtained.

The energy consumption of the sole should not exceed 3 W. If the voltage drops due to this limit, the actual voltage used during the test should be noted in the report.

China Labor Insurance Network