top of page

NEXUS

M&E DESIGN

Electrical Design - 🔍 What Are Harmonics?

  • Writer: MTS DNC ENERGY CONSULTANTS LIMITED
    MTS DNC ENERGY CONSULTANTS LIMITED
  • Oct 27
  • 2 min read
ree

Harmonics are unwanted distortions in electrical waveforms caused by non-linear loads — devices that draw current in short pulses rather than in a smooth, sinusoidal manner. These distortions can compromise voltage stability and increase system losses.


Common sources of harmonics include:

💡 Inductive luminaires and LED drivers

💻 Computers and office electronics ⚙️ Rotating machines and electronic speed controllers

🔋 Uninterruptible Power Supplies (UPS)

🔥 Arc furnaces and industrial switching devices


⚠️ Problems Caused by Harmonics

Voltage Distortion (Notching)  

When harmonic currents flow, they distort the voltage waveform — a phenomenon known as notching. This is especially severe in high-impedance systems, such as standby generators, where voltage drops occur with every switching pulse. The result?

  • Malfunctioning sensitive equipment

  • Reduced power quality

  • Erratic operation of control systems


High Neutral Currents — A Critical Concern

In three-phase, four-wire systems (TPN), third-order harmonic currents from each phase combine in the neutral conductor. Unlike balanced loads, these harmonics do not cancel out — they accumulate. This can lead to:

  • Severe overheating of neutral conductors

  • Elevated fire risks

  • Premature insulation breakdown

🚨 Therefore, in installations with high harmonic content, the neutral conductor must NEVER be undersized.   Reducing the neutral in multicore cables may seem cost-effective, but it poses serious safety and performance risks. The neutral must be kept the same size as the phase conductors to safely carry the additive harmonic currents and prevent catastrophic failures.


🧠 Engineering Solutions

To ensure compliance and safe operation, electrical engineers must proactively address harmonics:

✅ Specify harmonic limits for all purchased equipment

✅ Require filters or input isolation transformers from manufacturers

✅ Maintain full-size neutral conductors in harmonic-prone installations

✅ Conduct harmonic analysis during the design phase


🌍 MTS DNC Electrical Design Expertise

At MTS DNC, we design every system with harmonic control in mind — enhancing reliability. Our services include:

  • Electrical load assessments

  • Harmonic and power quality analysis

  • HV/LV distribution design

  • Integration of filtering and mitigation solutions

We serve residential, commercial, and pharmaceutical sectors with robust, compliant, and efficient electrical designs.


⚙️ Related Services

  • BER Assessment

  • Energy Audits & Modelling

  • HVAC & Heating Design

  • Drainage & Civil Design


📞 Ready to Improve Power Quality?  

Contact MTS DNC Energy Consultants today to assess your electrical systems and ensure full harmonic compliance.


Disclaimer: The content shared in these posts is intended for informational purposes only and should not be interpreted as design advice, specifications, or a calculation template. For professional guidance or design services, please contact us through our contact form.


bottom of page