What Should I Do If Water Enters The Distribution Box? Is There Any Good Solution?

1. Check the contactor

The contactor should also check the wiring terminals first, the method is the same as the circuit breaker. Then it is also necessary to open the cover for inspection. Loosen the front cover fastening screws, open it, and focus on checking the contacts and arc extinguishing cover. The contact inspection method is the same as the circuit breaker. Check for water marks and clean it. If necessary, polish it with fine gauze paper, but be careful not to over-polish it. The gap of the arc extinguishing cover is relatively narrow, blow it dry carefully, and do not leave any water.

Then the contactor coil needs to be checked. Observe whether there is water accumulation in the coil. After drying for one day, check the DC resistance of the coil. Generally, the DC resistance of the coil will be marked on the coil. Compare it with the value of the multimeter. If the difference exceeds 20%, it is basically unusable and needs to be replaced. The auxiliary contacts of the contactor and the external auxiliary contacts should also be checked. They are also disassembled, the accumulated water is cleaned, and the contacts are checked.

After all the inspections are completed, the contactor cover is reset and the insulation is measured with an insulation tester. The requirements are the same as those of the circuit breaker. Then connect the temporary power supply, energize the closing coil, check the contactor action, and use a multimeter to check whether the main and auxiliary contacts are in good condition.

2. Check the circuit breaker

The load of the distribution box is the fire pump and the water supply pump. These circuits will at least have circuit breakers and contactors. Let's talk about the circuit breaker first.

For circuit breakers that have been soaked in water, first check the upper and lower terminals, loosen the copper plate or cable and cable nose, clean the accumulated water, clean the contact surface, and polish it if there is rust. Then open the cover to check. If the circuit breaker has an additional operating mechanism, remove the operating mechanism first. Then remove the fixing screws of the circuit breaker, usually four to five, and unscrew them from the front of the circuit breaker. Remove the front shell and see if there is any water inside the circuit breaker. If there is, wipe it clean, dry it, or blow it dry. Check whether the moving and static contacts of the circuit breaker are abnormal, whether there is oxidation and stains after water immersion, if so, polish them clean with 500-grit fine sandpaper. Remember not to over-polish to avoid affecting the contact pressure and contact effect.

Next, if there are tripping coils and auxiliary contacts in the circuit breaker, they need to be checked separately. The tripping coil can be checked for direct resistance with a multimeter to determine whether there is a broken wire; observe whether there is water accumulation in the coil. If so, it is recommended to replace it; according to the rated voltage of the coil, select a temporary power supply to try whether the coil can operate normally. For the auxiliary contacts, first check whether there is water accumulation. After cleaning, you can use a tool to press the contact mechanism and use a multimeter to check whether the contact is on and off normally. If not, replace it.

If the circuit breaker is equipped with leakage protection, check the leakage protection circuit and coil in the same way as the tripping coil. After completing the above checks, reset the circuit breaker, manually open and close the circuit breaker several times, and use a multimeter to check the on and off of each phase of the circuit breaker. Use an insulation tester to measure the insulation resistance between each phase of the circuit breaker and each phase to the ground. According to the specification, it is greater than 0.5 megohms to meet the requirements, but in actual operation, it is recommended to be greater than 2 megohms.

3. Check the PLC and inverter

These two things may be in the distribution box. If they are soaked in water, it is not easy to blow dry the water if the cover is not opened for comprehensive cleaning. The inspection is complicated. It is recommended to remove them and hand them over to professionals for detailed inspection. Check the functions of the inverter and PLC item by item, and repair or replace them. The PLC eeds to be re-programmed, and the inverter needs to be re-parameterized.4. Check the cable5. Check the secondary circuit

The secondary circuit may have buttons, indicator lights, fuses, current and voltage meters, energy transformers, current transformers, etc. Check them one by one. Disassemble and check those that can be disassembled. Dry thoroughly those that cannot be disassembled. After the inspection, check the insulation of the secondary circuit, not less than 0.5 megohms.

The above content is what you need to pay attention to after the distribution box is flooded. I hope it will be helpful to everyone. Of course, you can also pay attention to SDKC to learn more about distribution boxes.https://www.kaichuanpower.com/