Md Nazmul Islam
Rules for Installing Switches and Sockets
General Rules
All plugs and socket outlets must be 3-pin type.
Provide an adequate number of sockets in each room.
In sub-power circuits:
Use only 3-pin, 16A sockets.
Each sub-circuit can supply a maximum of 2 sockets with total load not exceeding 3000W.
Appliances requiring more than 16A must be controlled by a double-pole switch.
Height...
Electrical Wiring Color Codes and Standards
IEC (most of Europe) AC power circuit wiring color codes
FunctionlabelColor, IECColor, old IECProtective earthPEgreen-yellowgreen-yellowNeutralNblueblueLine, single phaseLbrownbrown or blackLine, 3-phaseL1brownbrown or blackLine, 3-phaseL2blackbrown or blackLine, 3-phaseL3greybrown or black
UK, AC: The United Kingdom now follows the IEC AC wiring color codes. Table below lists these along with the obsolete domestic color codes....
National Electrical Code (NEC) Basics Every Electrician Should Know
What is the NEC?
The National Electrical Code (NEC) sets the standard for safe electrical wiring and equipment installation in the U.S.
Published by the National Fire Protection Association (NFPA).
Updated every 3 years to include new technologies and safety practices.
Covers everything from wiring inside walls to panels, breakers, batteries, solar, and...
How to Prevent Electrical Shocks on the Job Site
Electrocution is one of the most serious hazards at work. Following simple precautions can greatly reduce the risk.
🔧 1. Use the Right Equipment
Choose double-insulated tools for extra protection.
Install and maintain Ground-Fault Circuit Interrupters (GFCIs) to cut power instantly when faults occur.
Test GFCIs regularly to make sure they work properly.
⚠️...
Safe Handling of Live Wires and Circuits
⚡ Safe Handling of Live Wires and Circuits
🔎 Hazards of Improper Handling
Electrical Shock – direct contact with live wires.
Fire Risk – overloaded/damaged wires can overheat.
Trip Hazards – loose or messy cables cause accidents.
Equipment Damage – poor installation harms devices.
📝 Pre-Installation Safety
Site Inspection – check for water, panels, foot traffic.
Plan...
Lockout/Tagout (LOTO) – Why It’s Important for Electricians
🔒 Lockout/Tagout (LOTO) – Why It Matters
⚡ What is Lockout/Tagout?
LOTO = Lock + Tag on equipment during repair, servicing, or maintenance.
Prevents unexpected startup or release of hazardous energy.
Required under OSHA Standard 29 CFR 1910.147.
Protects electricians, machine operators, laborers, and other workers.
🛡️ Why It’s Important
Creates an Electrically Safe Work Condition...
Personal Protective Equipment (PPE) in Electrical Work
🛡️ Types of PPE
Head Protection – Hard hats with electrical insulation.
Eye & Face Protection – Safety glasses, goggles, face shields (for sparks/arc flash).
Hearing Protection – Earplugs for noisy equipment.
Hand & Arm Protection – Insulated gloves, rubber lineman gloves, protective sleeves.
Foot & Leg Protection – Non-conductive safety shoes, dielectric overshoes.
Body...
Basic Electrical Safety Rules Every Electrician Must Follow
Keep equipment away from water – Maintain at least 5 feet distance and use GFCIs to prevent shocks and fire hazards.
Unplug safely – Always pull from the plug, not the cord, to avoid damage and electric shock.
Install & tidy cords – Ensure proper installation and keep cords neat and...
Resistor
A simple circuit with a single resistor connected to a voltage source (battery).
Charges move through the resistor from the positive terminal of the source to the negative.
The animation often shows little dots or markers representing electric charge or current flow.
From the resistor’s point of view
The resistor resists the flow...
Fourier series triangle wave circles
What a triangle wave is
A triangle wave is a periodic waveform that linearly ramps up then linearly ramps down (or vice versa), forming a triangular shape.
It has slope changes at the peaks (sharp corners), unlike sine waves which are smooth.
What Fourier series does here
Fourier series lets you express a...
Square Waveform
What is a square wave
A square wave is a periodic waveform that switches between two levels (for example +A and −A, or “on” and “off”) with instantaneous transitions.
It’s one of the basic waveforms in electronics, signal processing, music synthesis etc.
What is shown in the image
The waveform alternates between two...
Sinusoidal wave
A Sinusoidal wave in the context of Electrical or Electronics Engineering is used to represent a time-varying voltage or current whose average value in a cycle is zero. Mathematically, this waveform can be represented by the equation.
