Identification of electric water heater leakage accidents

When the water heater leaks electricity, it is easy to cause electric shock when the human body comes into contact with the leaking parts. Mild cases may cause symptoms such as pain and numbness, while severe cases may lead to cardiac arrest, difficulty breathing or even death. Water heater leakage may cause a short circuit and cause a fire. Fires not only cause property damage but can also endanger lives. Water heater leakage may cause damage to key components such as circuit boards and heating pipes, affecting the normal use of the water heater, and even causing the entire machine to be scrapped.

Zhongke Testing and Appraisal Institute can provide electric water heater leakage accident identification services, and make accurate identifications of trace evidence analysis and accident cause analysis in various electric water heater leakage accidents.

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Check the nameplate mark of the electric water heater to see that the content is clear and complete, and the warning statement is eye-catching; the power cord and plug are in good appearance; the power socket used is a socket with a waterproof cover, and the appearance of the socket is normal.

1. Insulation resistance test: Test from the N and L poles of the electric water heater power cord plug to the ground electrode, the water outlet of the electric water heater and the metal snakeskin tube for the shower head connected to it. The results are all 0, indicating that the water heater has insulation failure.

2. Internal structure inspection: Disassemble the electrical distribution and control parts of the electric water heater to find the location of insulation failure, check that the N pole, L pole, and ground pole wiring of the power cord incoming terminal are all reliable, and the electric heating tube wiring is reliable and covered with an insulating sleeve. The pipe, electrical clearance and creepage distance are all greater than 3mm. No signs of insulation failure were found in the above parts; only one thermal circuit breaker was not reliably fixed. The two terminals of the thermal circuit breaker were covered with black insulating sleeves. They felt hard and brittle. The position near the bottom was cracked and there were obvious burn marks.

Since the thermal circuit breaker is not reliably fixed, during the use of the water heater, the position and shape of the thermal circuit breaker itself will change due to heating expansion, vibration and other factors. When the electrical gap between the live parts and the accessible metal conductor of the electric water heater is reduced to 0, a ground short circuit fault occurs.

3. Troubleshooting inspection: Move the thermal circuit breaker inside the water heater to its original position and test the insulation resistance again. The results are all above 500 MΩ.

A consumer purchased an electric water heater produced by an electrical appliance company on a certain day and put it into use after being installed by the company's service personnel. The water heater had been repaired three times by the electrical appliance company. On one day, the consumer was electrocuted while using the water heater to take a bath.

Entrusted by the court, a third-party appraisal agency conducted a technical appraisal of the "power cord plug electric shock" to find the direct cause of the accident.

Appraisal analysis results:

Appraisers went to the site of the incident to conduct inspections, and representatives of the company involved cooperated and made detailed statements. Based on the information learned during the on-site inspection, the analysis of the causes of the "electric water heater leakage" incident involving injuries to people is as follows:

The reason for the insulation failure of the electric water heater itself is that the electric water heater has the following hidden dangers after repairs:

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