Issues regarding the power distribution cabinet of electric heating boilers
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Recently, the company worked on an electric heating boiler project. After acceptance, the client raised the following issues: 1. There are no neutral or ground bars in the distribution cabinet. 2. The busbars in the distribution cabinet lack color coding and are not tinned. 3. The ground wire on the secondary side of the current transformers in the distribution cabinet should be connected to the ground bar rather than to the cabinet body. 4. The BV10 square millimeter plastic-copper wires used in the distribution cabinet have not been tinned, and in some cases, the BV10 square millimeter plastic-copper wires at the outlets are not connected using terminal fittings. 5. The door of the distribution cabinet is not securely connected to the cabinet body and the ground bars. 6. It is strictly prohibited to make any holes in the side panels of the distribution cabinet. 7. No overall leakage protection is installed in the electronic control system. Could everyone please help check whether these requirements are reasonable? For example, whether the total leakage can be measured separately outside the cabinet, whether copper wires must be tinned, whether it is feasible to use ordinary insulating materials, whether ground and neutral bars are necessary, and whether there are any relevant standards. Thank you all!
I think the following points are unreasonable: 1. There are no neutral or ground bars in the distribution cabinet, although they are actually needed. 2. The busbars in the distribution cabinet lack color coding and are not tinned; according to regulations, busbars should be of this kind. 3. The ground wire on the secondary side of the current transformers in the distribution cabinet should not be connected to the cabinet body but rather to the ground bar. 4. In some cases, the BV10 square millimeter plastic-copper wires at the bottom of the switches were not connected using terminal fittings. 5. The doors of the distribution cabinet are not securely connected to the cabinet body and the ground bar. 6. Holes must not be made in the side panels of the distribution cabinet. The following is a bit excessive: 7. There is no overall leakage protection device installed in the electrical control system, and the BV10 square millimeter plastic-copper wires used in the distribution cabinet have not been tinned
I think Toho’s requests are reasonable and not excessive; your company’s work is indeed a bit sloppy – you need to boost your safety awareness
For the main incoming circuit, a circuit breaker with isolation function and leakage protection is sufficient. .
It should be considered a fairly standard requirement. However, I have no experience with the third point. Article 6: I have some doubts as an individual; I’m not sure if my understanding is correct. It seems that holes can also be made on the sides for ventilation, right?
We are boiler manufacturers and are not familiar with the electrical specifications. Since it had always been done this way before, and no customers seemed to raise any objections, I wasn’t aware of these issues. Thank you to everyone who replied above.
What they are asking for is reasonable and standard; it’s likely that the manufacturer you’ve chosen is a fake one, producing shoddy products that fail to meet even the basic requirements, which is why they were caught!
1. There are no neutral busbars or ground busbars in the distribution cabinet; such busbars must be present in the distribution cabinet. 2. The busbars in the distribution cabinet lack color markings and are not tinned; it is required that the three phases have colored markings and be tinned. 3. The ground wire on the secondary side of the current transformer inside the distribution cabinet should not be screwed onto the cabinet body, but rather onto the ground bar, and this must be done correctly. 4. The BV10 square millimeter plastic-copper wires installed in the distribution cabinet have not been tinned; in some cases, the BV10 square millimeter plastic-copper wires at the bottom of the switches have not been connected using terminal lugs. Multi-strand flexible wires must be tinned and connected with terminal lugs. 5. The door of the distribution cabinet is not securely connected to the cabinet body and the ground bus; the door must be firmly connected to the panel cabinets using wires. 6. Holes are strictly prohibited on the side panels of the distribution cabinet. Determine whether openings can be made, etc., based on the protection level requirements. 7. There is no overall leakage protection installed in the electrical control system. The presence of a leakage protection function is determined based on the power supply requirements of the panel cabinet; if it is the overall power supply for the boiler, it is recommended not to add a leakage switch, but rather to equip the branch switches used by personnel with leakage protection.
Their requirements are completely correct; whether to install a leakage circuit breaker depends on what is specified in the design drawings. For the other issues, your company should handle them in accordance with the relevant standards. If your company doesn’t even know this, it’s better to close down.