Md Nazmul Islam

Overview When more than three current-carrying conductors are installed together in the same raceway, cable, or bundled group, their ability to dissipate heat decreases. To prevent overheating, the ampacity (current-carrying capacity) of each conductor must be reduced according to the adjustment factors listed in Table 310.15(B)(3)(a). Adjustment Factors Number of ConductorsPercent of Ampacity...

Purpose NEC Table 310.16 provides the allowable ampacity (current-carrying capacity) of insulated conductors rated 0 – 2000 volts. It is one of the most used tables in the NEC — helping electricians size wires safely based on insulation type, temperature rating, and installation conditions. Understanding the Table Ampacity depends on several factors: Conductor Material...

Purpose Article 215 of the National Electrical Code® (NEC®) establishes the requirements for the installation, sizing, and protection of feeder circuits — the conductors that carry power from the service equipment to branch circuit panels or distribution equipment. Proper feeder design ensures safe power delivery without overheating or voltage drop. Key Concepts Definition...

Purpose Article 210 of the National Electrical Code® (NEC®) defines the requirements for branch circuits — the final wiring that delivers power from panelboards to outlets, lighting, and equipment. It ensures branch circuits are safely sized, protected, and installed to prevent overheating and electrical hazards. Key Concepts Definition (210.2) A branch circuit is...

Purpose Article 200 of the National Electrical Code® (NEC®) defines the rules for identifying, connecting, and using grounded conductors — commonly known as neutral conductors. These rules ensure that electrical systems remain safe, properly referenced to earth, and free from unwanted current flow on equipment grounding paths. Key Concepts Definition A grounded conductor...

Purpose Article 110 of the National Electrical Code® (NEC®) outlines the fundamental safety requirements for all electrical installations. It ensures that equipment is installed, maintained, and operated safely, reducing risks of shock, fire, or mechanical failure. Key Areas Covered 110.2 – Approval All electrical equipment must be approved by the Authority Having Jurisdiction...

Purpose Article 100 of the National Electrical Code® (NEC®) provides clear definitions for terms used throughout the Code. Understanding these definitions is essential because NEC requirements depend on how each term is officially defined — not just what it sounds like in everyday language. Key Concepts The NEC uses precise definitions to avoid...

Purpose Article 90 of the National Electrical Code® (NEC®) defines why the Code exists — to ensure electrical systems are safe, reliable, and free from hazards that could cause shock, fire, or injury. It establishes the NEC as a minimum safety standard for electrical design, installation, and inspection. Scope (What the NEC...

Automatic Changeover Switch Connection An Automatic Transfer Switch (ATS) switches power between the main grid and a backup generator to keep the load running without interruption. Key Components Main Grid →...

This diagram shows the internal and external parts of an oil-filled power transformer, an essential device used to step up or step down voltage in electrical systems. The primary winding and secondary winding are wound on the core, which provides a magnetic path for energy transfer.The main tank holds...

This diagram explains how to build a basic 12V audio amplifier circuit using the AN7523N IC. It’s ideal for powering small speakers (like a 6-inch unit) and can be used for home audio projects, DIY speaker systems, or learning amplifier fundamentals. Key Components: IC AN7523N: The main amplifier chip that boosts...

This wiring diagram demonstrates how to automate water tank filling using a water level controller and motor pump. The setup ensures the tank fills automatically when water levels drop and stops when it’s full — saving electricity and preventing overflow. Key Components: Water Level Controller: Detects the water level and controls...