What should I do if the current probe accidentally gets wet?

Introduction
If a current probe gets soaked in water, it must be treated promptly and according to proper procedures. If moisture remains, it will rapidly corrode the magnetic core, Hall element, and internal circuitry, degrading insulation performance and, in severe cases, completely destroying the probe.

So, how should a probe be handled if it gets soaked in water? The best practice is to follow a four-step process: "Disconnect power - Drain water - Dry - Test," ensuring that each step avoids secondary damage.

Step 1: Quickly disconnect and isolate the probe
The first priority is to immediately disconnect the probe from external devices, including the oscilloscope, the device under test, and the power supply system, to reduce the risk of short circuits or electric shock.

If the probe is battery-powered, it should be removed promptly to prevent residual current from continuing. Tests have shown that if the battery is not removed promptly, the rate of internal corrosion in the probe can increase significantly within 12 hours. Test data from 2023 shows that the failure rate of probes that were soaked in water without power isolation was over 60% higher than that of probes that were promptly de-energized.

Step 2: Drain visible water
After confirming that the power is off, the next step is to drain any accumulated water. Hold the probe tip downward and gently shake it to allow the liquid to drain naturally. Avoid vigorous shaking, as this may cause moisture to penetrate deeper into the probe.

For the probe housing and connector surfaces, gently blot dry with lint-free paper or a microfiber cloth. However, be sure to avoid touching the internal circuitry or directly wiping components, as this can damage solder joints and even introduce static electricity risks.

Practical examples have shown that residual fibers on the PCB can absorb moisture later and cause leakage current. Therefore, this step requires careful and meticulous attention.

Step 3: Drying in a Controlled Environment
Drying is crucial to the repair process. Avoid direct heating methods such as baking, using a heat gun, or using a hair dryer. While these methods can quickly evaporate moisture, they can accelerate metal oxidation and impose thermal stress on the magnetic core and electronic components, leading to irreversible performance degradation.

The scientific approach is to use a sealed, dry environment:
Place the probe in a sealed container and fill it with a sufficient amount of electronic-grade silica gel desiccant (food-grade desiccants are prohibited).

Seal the container and store it at room temperature between 25–30°C.

Dry for at least 72 hours. If the humidity is too high, extend this to approximately 7 days.

If silica gel desiccant is unavailable, place the probe in a moisture-proof cabinet, maintaining the humidity below 10% RH, for at least 48 hours.

Research results show that probes dried with silica gel have an 85% functional recovery rate; however, probes dried with heat have an accuracy recovery of less than 50% and exhibit significant long-term drift.

Step 4: Testing and Professional Repair
After drying, the probe must be tested before use. First, use a multimeter to measure the insulation resistance between the probe connector and ground. Any abnormal reading (close to 0Ω or infinite) indicates a short or open circuit.

At this point, the probe should never be connected directly to an oscilloscope or test bench. Instead, it should be taken to the manufacturer or a certified repair center for inspection. Common professional inspections include:
Circuit board corrosion inspection;
Core performance testing to confirm demagnetization or damage;
Dielectric strength testing, especially required for high-voltage probes;
Recalibration to ensure reliable measurement data.

Self-powered testing is extremely risky:
Residual moisture can instantly cause circuit breakdown;
Even if the surface is dry, oxidation of internal contacts and degradation of the core performance can still affect accuracy.

Users are advised to keep records of any probe anomalies and send them with the device for repair. According to repair centers, probes with complete fault records can reduce repair cycles by approximately 30%.

Additional Tip: Safety Certification and Affordability
Unless a probe is IP67 waterproof, water ingress automatically voids its CE/IEC safety certification. Continued use poses a potential risk of electric shock or fire.

From a financial perspective, probe repair costs can often exceed 50% of the original price. If the core or main chip is damaged, replacing the probe is often more cost-effective than repairing it.

According to a 2022 industry survey, nearly 70% of laboratories prefer to replace damp probes directly rather than repair them, primarily due to the difficulty in ensuring long-term reliability. This demonstrates once again that in the field of high-precision measurement, safety and accuracy far outweigh cost savings.

Conclusion
Handling a current probe after it has been soaked in water is essentially a battle of time. The sooner you disconnect the power, the more thoroughly you dry it, and the more rigorously you test it, the greater the chance of recovery.

Never assume that simply letting it air dry is enough for use. Even trace amounts of residual moisture can gradually corrode the magnetic core or circuitry over several weeks, ultimately causing irreversible damage.

Therefore, only by combining emergency measures with daily preventative measures, such as proper storage, the use of protective covers, and avoiding high-humidity environments, can you truly ensure probe safety and measurement reliability.