Why doesn’t the circuit breaker trip when the wires are burning?
When we are doing after-sales service for our electrical switchboard, distribution panel board,we often hear customers ask that why the wires are burnt, but the air circuit breaker does not trip.
Today, Jiangxi Yikai electric will answer this question.
The function of the circuit breaker in the circuit is to automatically break the circuit when overload, short circuit and voltage loss exceeding the allowable limit occur, as well as infrequent connection and breaking of the circuit under normal conditions. The function of the wire should be able to carry the needs of the maximum load current, and should be able to withstand a certain mechanical tension and withstand a certain voltage.
The problem now is that the circuit breaker does not trip when the wires are burned. Based on this analysis as follows:
1. The current-carrying capacity of the wire is selected incorrectly.
The selection of wires generally must comply with factors such as safety, and resistance to mechanical tension.
The safe current carrying capacity of the wire should generally be greater than 1.5 times the rated current of the electrical load.
Choose different wires according to different device wiring. Such as plastic sheathed wire, plastic cable wire, single strand, multiple strands of plastic copper core, aluminum core and other wires.
Different wires should also be selected according to different places, such as dust, high temperature, humidity, cultural and entertainment places, and stages have different requirements.
The selection of wires should preferably meet the national standards.
Electrical installation must understand the electrical requirements, and the maximum rated current must be known to correctly select the wire specifications that meet the requirements.
2. The wrong rated current of the circuit breaker is selected.
Wrong selection of MCB rated current. In the circuit, the circuit breaker is the main power switch.
The general selection principle of the rated current of thecircuit breaker is 1.2 times the total rated current of the line electrical appliances.
If the selection is too large, when there is an overload in the line, the air circuit breaker will delay or even refuse to move.
If the circuit breaker is too small, it will trip and affect normal use.
In addition, we should be paid to the adaptability of the place when selecting a circuit breaker.
The adaptability of the rated current should be considered when selecting the air switch.
Different circuit breakers are selected in terms of breaking capacity, sensitivity and fast action.
3. There may be irregularities in the wiring device.
The installation should be standardized in the circuit.
Observe the electrical pressure regulations and carry out electrical installations according to requirements
, and also comply with the low-level requirements during inspection to ensure safety.