Electrical noise is one of those mysterious occurrences that always seems to create issues. Some causes of electrical noise are well-known; for example, a laser copier requires an internal heater to kick in on every use, causing rapid changes in the current that may create noise. Other times, however, electrical noise seems to appear out of thin air.
Want to shed light on this mystery? This short guide will teach you more about the causes of electrical noise and how it allows you to identify issues with your appliances!
What Is Electrical Noise?
We use the term “electrical noise” for a variety of electrical system issues. In simple terms, this type of noise refers to any random variation in voltage or current. These variations are usually of relatively low amplitude, but they can still disrupt or damage your electrical circuits.
The key to understanding electrical noise is learning how to decode each sound. Knowing when a particular noise is alarming and reducing it can help you prevent electrical failures.
Basic Mechanisms of Noise Coupling
Electrical noise can involve four basic noise coupling mechanisms. These include:
- Capacitive coupling: Voltage-based effect, such as a lightning discharge, often referred to as electrostatic noise
- Conducted noise: Noise coupled by galvanic, direct connections, such as circuits that have shared conductors
- Inductive coupling: Magnetic-coupled noise and a current-based effect
- RFI (radio frequency interference): At certain frequencies, wire lengths act like receiving and transmitting antennas
Common Causes of Electrical Noise
Most households have plenty of components that can produce electrical noise, from switches to relay contacts. Predicting these issues is tricky, but they usually occur due to erratic systems or fluctuating digital indicators. Here are some common causes of electrical noise:
- High Voltage Start-Up
When drives, motors, and other high-voltage units are running, some voltage will be discharged to the ground every time they start and stop. Part of this voltage may result in electrical noise. Metal oxide varistors (MOVs) can help prevent noise issues.
- Wiring
Communication cables are fairly susceptible to electrical noise. For instance, power cables often cause noise issues if they’re bundled with signal cables, so keep them away from each other. If possible, use fiber optic cables since they have lower EMF interference.
- Insulation Issues
The insulation barrier of the cable shielding is what keeps the voltage running freely. If the insulation is damaged, voltage variations will occur more frequently and generate more noise.
- Temperature
An increase in circuit temperature causes free electrons to move more quickly, creating voltage variations and thermal runoffs. To avoid these issues, keep your electronics as cool as possible.
