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⚡ ELECTRICITY & ELECTRICAL SAFETY – (Study Guide)
🔍 Why Understanding Electricity Matters
Helps you use and maintain tools safely and correctly.
Enables proper care of electrical equipment.
Electricity powers salon lighting, heating tools, and client services.
⚙️ Basic Concepts
| Term | Definition / Key Idea | Example |
|---|---|---|
| Electricity | Movement of electrons from one atom to another through a conductor; produces magnetic, chemical, or thermal effects. | — |
| Electric Current | Flow of electricity along a conductor. | — |
| Conductor | Material that allows electricity to pass easily. | Copper wire |
| Insulator (Non-Conductor) | Material that resists electrical flow. | Rubber, wood, glass, cement |
Wires = metal threads (conductor) + rubber/plastic cover (insulator).
🔄 Two Types of Current
| Type | Description | Source / Examples |
|---|---|---|
| Direct Current (DC) | Constant, even flow → one direction only. | Flashlights, cell phones, cordless tools (battery-powered). |
| Alternating Current (AC) | Rapid, interrupted flow → reverses direction 60×/sec. | Hair dryers, electric files, lamps plugged into wall. |
🔢 Electrical Measurements
| Unit | Symbol | Measures … | Example |
|---|---|---|---|
| Volt (V) | Voltage | Pressure / force pushing current. | 12 V (car battery), 120 V (wall socket), 240 V (dryer). |
| Ampere (A) | Amps | Strength of current. | Hair dryer 12 A = thicker cord than 6 A. |
| Milliampere (mA) | — | 1/1000 of an amp → used in facial treatments. | — |
| Ohm (Ω) | — | Resistance to current flow. | — |
| Watt (W) | — | Energy used per second. | 40 W bulb = 40 W per second. |
| Kilowatt (kW) | — | 1000 W; household billing uses kWh. | — |
🔐 Electrical Safety Devices
| Device | Function | Notes |
|---|---|---|
| Fuse | Melts/blows when too much current flows → breaks circuit → prevents fire. | Replace after disconnecting and checking connections. |
| Circuit Breaker | Switch that automatically shuts off overloaded circuit. | Reset manually (no replacement needed). |
Rule: If a wire is too small for the current, it overheats → fire risk.
🌍 Grounding & GFI
Grounding: Completes circuit and safely carries current away.
Two-prong plug → one blade wider = one-way insertion (prevents shock).
Three-prong plug → adds ground pin = extra protection if wire comes loose.
Ground Fault Interrupter (GFI) → detects leaks of a few mA, cuts power instantly.
Green light = OK; Red = tripped → press Reset.
✅ UL Certification (Underwriters Laboratories)
UL logo = appliance tested and safe when used per manufacturer’s instructions.
Always buy and register UL-listed devices.
🧯 Guidelines for Safe Use of Electrical Equipment
Use UL-certified appliances only.
Read instructions before use.
Register appliances to receive recall notices.
Unplug by the plug, not the cord.
Disconnect before cleaning.
Never insert pins or wires into appliances.
Inspect regularly.
Keep cords and plugs in good condition.
One plug per outlet (use surge-protected power strip if needed).
Avoid water or metal contact when using electricity.
11–21. (See textbook p. 191 for additional rules.)
⚠️ Electrical Emergency Steps
If you feel a shock when plugging/unplugging tools (< 500 W):
Stop using it immediately.
2–10. Follow page 191 for disconnecting and reporting procedure.
💆♀️ Facial & Electrotherapy Basics
| Term | Meaning |
|---|---|
| Electrotherapy | Use of electrical currents for skin treatment. |
| Modality | Specific type of current used for face/scalp treatments. |
| Electrode (Probe) | Applicator that directs current to skin. |
| Polarity | + or – charge of current. |
| Anode | Positive electrode (red, +). |
| Cathode | Negative electrode (black, –). |
Each modality requires two electrodes (one positive & one negative).
💡 Light Energy & The Electromagnetic Spectrum
| Light Type | Description / Use |
|---|---|
| Visible Light | 35% of sunlight; Violet = shortest wave, Red = longest (R-O-Y-G-B-I-V). |
| Invisible Light | Beyond visible range — cannot be seen by eye. |
| Ultraviolet (UV) | Short wavelength = high energy; stimulates Vitamin D; overexposure → aging & cancer. |
| Infrared (IR) | Long wavelength = heat therapy effect. |
| Radio/Micro/X-/Gamma Rays | Other forms in the spectrum (radio, microwave, medical x-rays, nuclear gamma). |
☀️ UV Light Types
Type | Details |
|---|---|
UVA | Longest UV wave; penetrates dermis; damages collagen & elastin; tanning beds. |
UVB | “Burning light” → sunburn & skin cancer risk. |
UVC | Blocked by ozone; kills microbes but deadly to life if ozone gone. |