Abstract

Note: Refer to this link for Part 1.

The role of a Designer Electrical Engineer (DEE) is pivotal in the successful planning, design, and lifecycle performance of electrical systems across a variety of sectors, including industrial, commercial, utility, and infrastructure. This article explores the essential core skills required by a DEE, focusing on four major design competencies: safety, equipment functionality, constructability, and maintainability. These core principles guide engineering decisions from concept to decommissioning, ensuring that systems are not only compliant and efficient but also practical and reliable. The article draws on international standards, professional engineering practices, and real-world project insights to articulate a comprehensive guide for current and aspiring design engineers.

1. Introduction

Designer Electrical Engineers are responsible for translating functional requirements into technical specifications and deliverables that can be built, operated, and maintained safely and efficiently. The scope of a DEE spans multiple disciplines: power systems, control systems, protection, instrumentation, and communication. Each design must account for dynamic conditions, regulatory compliance, budget limitations, and long-term asset performance.

Electrical engineering design is not solely about connecting loads to power sources or specifying equipment sizes—it demands an integrated approach. A competent DEE must think in terms of system behavior, fault tolerance, future expandability, and real-world operating conditions. This holistic view is grounded on four cornerstones:

Safety – ensuring life, property, and system protection.
Functionality – assuring equipment performs as intended.
Constructability – enabling practical and cost-effective implementation.
Maintainability – allowing continuous, efficient, and safe operation over time.

Each of these pillars interrelates; a design that's functional but unsafe is unacceptable. Likewise, a safe but unbuildable or unserviceable design holds no practical value. Hence, mastering these core skills is essential for delivering successful electrical designs.

2. Safety Familiarization and Integration

2.1 Codes and Standards

One of the first responsibilities of a DEE is understanding and applying relevant electrical safety codes. Globally recognized standards include:

IEC 60364: Electrical installations of buildings.
NFPA 70 (NEC): National Electrical Code (USA).
IEEE 1584: Guide for Arc Flash Hazard Calculations.
IEC 60079: Explosive Atmospheres (Hazardous Areas).
OSHA and NFPA 70E: Electrical safety in the workplace.

In the Philippines, for example, PEC (Philippine Electrical Code) Parts 1 and 2 govern compliance, adapted from the NEC and aligned with IEC principles.

The DEE must not only be familiar with the content of these codes but must be capable of interpreting them in context—choosing the correct application based on site-specific constraints, utility regulations, or client requirements.

2.2 Hazard Identification and Risk Assessment

Safety by design begins with identifying possible hazards. A DEE should conduct formal hazard and operability studies (HAZOP) or electrical risk assessments, especially for complex or high-risk environments such as chemical plants, refineries, or data centers.

Common electrical design hazards include:

Inadequate fault protection
Improper grounding or bonding
Insufficient segregation of power and signal cables
Overloaded circuits
Unprotected live parts

2.3 Electrical Safety by Design

A DEE must incorporate engineering controls to eliminate or mitigate hazards, such as:

Using residual current devices (RCDs) for personnel protection.
Ensuring touch voltage limits (as per IEC 60479).
Implementing selective coordination in protection schemes.
Designing fail-safe systems (e.g., contactor drop-out on emergency stop).
Applying IP-rated enclosures suited to environmental exposure.

Safe isolation should be integral to any design—clear demarcation of live components, safe switching access, and provision of lock-out/tag-out systems are essential.

2.4 Earthing and Bonding Systems

Correct earthing and bonding not only prevent electric shock but also reduce electromagnetic interference and ensure system stability. The DEE must determine the appropriate earthing system—TT, TN-S, TN-C-S, or IT—based on system configuration, fault current availability, and regulatory requirements.

Key design considerations include:

Sizing of earthing conductors (per IEC 60364-5-54)
Earth electrode resistance values
Potential rise during faults
Separation of instrumentation and power grounds

2.5 Arc Flash and Overcurrent Protection

Arc flash incidents can cause severe injury or death and damage equipment. The DEE must perform arc flash energy calculations and specify protective devices accordingly. The following steps are typical:

Performing short circuit analysis (IEEE 551/IEC 60909).
Defining incident energy levels using IEEE 1584 formulas.
Specifying personal protective equipment (PPE) categories.
Designing zoned protection with fast-acting breakers or arc quenching devices.

The DEE must also ensure that protective devices are correctly coordinated to isolate faults while minimizing disruption, using time-current coordination studies.

3. Functional Knowledge of Electrical Equipment

3.1 Power Systems and Distribution

A DEE must have a robust understanding of power system fundamentals—single-line diagrams, load centers, transformer sizing, distribution configurations, and voltage drop calculations. Knowledge of system topologies such as radial, looped, or mesh networks is critical, especially in medium voltage (MV) and high voltage (HV) systems.

A key competency is the ability to design distribution systems that are both technically adequate and economically optimized, including selection of conductor sizes, switchgear ratings, and transformer tap settings to suit load profiles and fault levels.

3.2 Switchgear and Protection Devices

Selection and coordination of switchgear and protection devices are essential for safety and reliability. A DEE must be familiar with:

Low Voltage (LV) and Medium Voltage (MV) switchgear
Air circuit breakers (ACB), molded case circuit breakers (MCCB), and miniature circuit breakers (MCB)
Protective relays: overcurrent, earth fault, differential, distance, and arc protection
Busbar schemes: single bus, double bus, ring bus, transfer bus

Knowledge of insulation levels, interrupting ratings, and protective device coordination ensures proper fault discrimination and equipment longevity.

3.3 Control and Automation

Automation is central to modern electrical systems. A DEE should understand PLCs, SCADA, HMIs, and control loop architecture. Designing control panels that integrate motor starters (DOL, star-delta, VFDs) with control logic is a core responsibility.

Familiarity with IEC 61131 for programming logic controllers and IEC 61499 for distributed control systems supports modular, scalable designs that are easier to operate and troubleshoot.

3.4 Renewable Integration and Smart Technologies

As systems increasingly incorporate renewable energy (solar PV, wind), DEEs must design for intermittency, grid code compliance, and inverter integration. This includes:

Grid-tied inverter configurations
Power factor control and reactive compensation
Energy storage system (ESS) interfacing
Net metering and microgrid architectures

3.5 Load Flow and Fault Studies

Before implementation, a DEE must validate designs through system studies:

Load flow analysis to confirm voltage profiles and transformer loading
Short-circuit studies for selecting withstand and breaking capacities
Harmonic analysis to mitigate power quality issues from nonlinear loads
Motor starting studies to avoid voltage dips

Proficiency in software tools like ETAP, DIgSILENT PowerFactory, or SKM Power*Tools is increasingly expected.

4. Constructability Considerations

4.1 Layout and Space Optimization

A design must be physically implementable. DEEs should collaborate with architects and civil engineers to ensure adequate clearances, equipment spacing, cable trench depth, and room ventilation. Use of 3D modeling (e.g., Revit MEP) allows clash detection and better spatial coordination.

Equipment dimensions, weight, and access requirements must be considered from the earliest design stages.

4.2 Cable Routing and Installation Practicality

Routing of cables affects thermal performance, voltage drop, electromagnetic interference, and safety. A DEE should:

Avoid sharp bends or excessive pulling tension
Consider derating factors for ambient temperature or grouping
Provide clear segregation between power and signal cables
Use tray and conduit systems that are accessible and code-compliant

4.3 Sequencing and Construction Phasing

Electrical design should account for the construction timeline. This includes provision for temporary power, logical sequencing of installation (e.g., underground conduits before slabs), and modular construction strategies. DEEs must work closely with contractors to incorporate realistic scheduling and minimize rework.

4.4 Material Selection and Availability

Specifying exotic or unavailable materials can delay a project. DEEs should be aware of local supply chains, lead times, and alternative equipment that meet the same technical standards. Familiarity with manufacturers' catalogs and certification requirements is essential.

Core Skills of a Designer Electrical Engineer – Part 2