The electrical panel design process is one of the most critical engineering steps to ensure that a facility’s power infrastructure operates safely, efficiently, and sustainably. An electrical panel is not merely a box that distributes energy; it is a hub where power flow is controlled, protective devices are managed, and operational continuity is maintained. Therefore, mistakes made during the design phase can lead to costly failures, occupational safety risks, and production downtime later on. Proper design is achieved by analyzing site requirements, selecting suitable components, establishing power balance, and creating a layout that complies with international standards.

Purpose and Importance of Electrical Panel Design

The primary purpose of electrical panel design is to ensure that energy distribution within a facility is carried out safely and in a controlled manner. Power is taken from source points and transferred to various equipment, machines, and circuits within the facility. Performing this transfer correctly reduces energy losses and minimizes safety risks.

The importance of design stands out in the following areas:

• Ensures stable and safe operation of the electrical system.
• Provides protection against hazards such as short circuits and overloads.
• Simplifies system maintenance, monitoring, and management.
• Improves energy efficiency and reduces operating costs.
• Safeguards occupational safety and employee health.

Accurate Determination of Power Requirements

The first step of panel design is to accurately calculate the facility’s total power demand. The voltage levels at which loads operate, instantaneous and continuous current values, peak loading conditions, and backup power requirements must be analyzed.

When determining power needs, consider:

• Nameplate ratings of machines and equipment
• Operating durations and commissioning scenarios
• Simultaneity factor (diversity factor)
• Future expansion potential

Without this analysis, the selected panel capacity is often either insufficient or unnecessarily costly.

Internal Layout and Cable Management

The internal layout of the panel is crucial for ease of maintenance and safe operation. Keeping cables neat and properly coded enables rapid intervention in the event of a fault.

Key principles of good cable management include:

• Power and signal cables should follow separate routes.
• Cable ducts must be sized according to load flow.
• Terminal blocks and connection points must be accessible.
• A standardized cable labeling system should be applied.

Poor internal wiring does more than create aesthetic issues; it increases the risks of overheating, electromagnetic interference, and fire.

Calculating Busbar Current-Carrying Capacity

Busbars are the main conductive elements that distribute electrical current within the panel. They must be selected to match the system’s current capacity. Busbar cross-section is determined by the material used (typically copper or aluminum), ambient temperature, and cooling conditions.

Key considerations in calculations:

• Nominal operating current
• Short-circuit withstand duration
• Thermal endurance
• Electrodynamic strength

Using undersized busbars can cause excessive heating and deformation at connection points.

Selection of Protective Devices (Fuses, Breakers, Relays, etc.)

The most important safety components in an electrical panel are the protective devices. Fuses, circuit breakers, and protection relays isolate the circuit in fault conditions to protect both equipment and personnel.

When selecting protective devices:

• Calculate prospective short-circuit current
• Ensure adequate breaking capacity
• Match thermal-magnetic characteristics to load behavior
• Configure relay settings for selectivity (coordination)

Incorrectly selected protection may fail to trip under fault conditions or may trip unnecessarily, causing production losses.

Short-Circuit and Overcurrent Withstand Calculations

Another critical step in panel design is analyzing short-circuit currents. The short-circuit level determines the system’s weakest link, and all components must safely withstand this current.

Calculations should consider transformer capacity, cable lengths, and busbar cross-sections. Overcurrent endurance defines the long-term operational safety of panel components.

Grounding and Residual Current Protection Systems

The grounding system ensures that the panel enclosure and conductive surfaces are safe against human contact. Residual current devices automatically disconnect the system in the event of insulation faults.

If grounding is not properly implemented:

• The risk of electric shock increases
• Fault current may not trigger protective devices
• Equipment may malfunction due to noise and interference

Ventilation, Cooling, and Thermal Management

Panel components generate heat during operation. If heat is not adequately dissipated, equipment life shortens and failure risk increases. Therefore, natural ventilation, forced-air cooling (fans), or air-conditioning units may be used in panel construction.

For temperature control:

• Continuously monitor internal ambient temperature
• Do not obstruct airflow
• Maintain spacing to limit heat transfer between components

Panel Sizing and Layout Planning

Panel size should be determined not only for current equipment but also with allowance for future expansion. An overly compact design creates maintenance difficulties and thermal accumulation.

When planning the layout, consider:

• Clearance for panel door opening
• Working space for maintenance personnel
• Directions of cable entry
• Wall and floor mounting conditions

Compliance Requirements with IEC and TSE Standards

The design and manufacturing of electrical panels must comply with IEC 61439, IEC 60364, and TSE electrical installation regulations. These standards define safety, protection classes, short-circuit withstand capabilities, and marking requirements.

Non-compliant systems:

• Create occupational safety risks
• Complicate insurance processes
• Lead to legal liability