Reasons For Overheating Of Components in The Distribution Box

Overheating of components in electrical distribution boxes is a phenomenon that requires serious attention. It can be divided into two types: normal overheating and abnormal overheating. Abnormal overheating is one of the main hidden dangers of electrical fires and must be investigated and dealt with promptly.

I. Connection Faults

These mainly occur at the connections between wires and components.

1. Loose Screws: Screws were not tightened during installation, or loosened due to thermal expansion and contraction or vibration after long-term operation. This increases contact resistance, generating a large amount of heat when current flows.

2. Improper Wiring: Burrs, oxidation, or insulation pressed into the terminal reduce the effective contact area.

Inappropriate copper lugs were used, or the connection was not secure.

Untinned or substandard pin terminals were used, causing partial separation and poor contact.

3. Loose or Insipid Connections: The connection appears to be made, but the actual contact point is very small, resulting in extremely high resistance.

II. Load-Related Issues

1. Overload: The current flowing through the circuit or component exceeds its rated current-carrying capacity for an extended period. For example, using too many high-power appliances or using excessively thin wires. The current exceeds the design capacity, causing components and wires to operate at high intensity continuously and generate heat.

2. Load Imbalance (Three-Phase System): Uneven distribution of three-phase loads leads to excessive current in one phase, causing overheating of the corresponding line and switching devices.

3. Harmonic Currents (Common in Commercial and Industrial Applications): High-frequency harmonic currents generated by nonlinear loads increase the effective current of the line, causing abnormal heating of the neutral line and related equipment.

III. Problems with the Components Themselves

1. Damaged or Aging Components:
Internal contacts may be burned or oxidized, leading to increased contact resistance.

Aging mechanisms result in sluggish operation, insufficient internal pressure, and poor contact.

Decreased insulation performance increases internal leakage current, generating heat.

Incompatible component specifications, such as using a switch with a low rated current to handle a high load.

2. Improper Component Selection:
Rated current is less than the load current, breaking capacity is insufficient, or the components are of substandard quality, made of poor materials, or have rough workmanship.

IV. Environmental and Installation Problems

1. Poor Heat Dissipation:
The distribution box is installed in a poorly ventilated, enclosed space.

Components are too densely packed inside the box, causing heat accumulation.

The box is covered or blocked by debris.

2. High Ambient Temperature:
Installation in high-temperature environments such as boiler rooms or direct sunlight results in high base temperatures.

3. Corrosive Gases or Dust:
Humid, dusty, or corrosive environments accelerate joint oxidation and insulation aging.

Regular temperature checks, using qualified components, standardized installation procedures, and proper load distribution are key to preventing overheating malfunctions. If abnormal overheating is detected, a professional electrician should be called in immediately to investigate and address the issue, preventing potential problems before they occur.