Explain the six major types of wiring systems.

1. Cleat Wiring: In this type of wiring system, cables are run along the walls or ceilings using porcelain or wooden cleats. The cables are held in place by clips or cleats, which provide support and protection. Cleat wiring is commonly used in industrial and commercial buildings.

2. Casing and Capping Wiring: This wiring system involves running cables inside metal or plastic conduits, known as casings and cappings. The cables are enclosed within the conduits, providing protection from mechanical damage and moisture. Casing and capping wiring is commonly used in residential and commercial buildings.

3. Conduit Wiring: Conduit wiring involves running cables inside metal or plastic conduits, which provide protection from mechanical damage and moisture. Conduit wiring is commonly used in industrial and commercial buildings, where the wiring needs to be protected from harsh environments.

4. Batten Wiring: In this type of wiring system, cables are run along wooden battens, which are fixed to the walls or ceilings. The cables are held in place by clips or cleats, providing support and protection. Batten wiring is commonly used in residential buildings.

5. Lead Sheathed Wiring: Lead sheathed wiring involves running cables inside lead sheaths, which provide protection from mechanical damage and moisture. The lead sheaths are then covered with an outer layer of insulation. Lead sheathed wiring is commonly used in underground and outdoor installations.

6. Surface Conduit Wiring: Surface conduit wiring involves running cables inside surface-mounted conduits, which are fixed to the walls or ceilings. The cables are enclosed within the conduits, providing protection from mechanical damage and moisture. Surface conduit wiring is commonly used in residential and commercial buildings where the wiring needs to be installed quickly and easily.

1. Knob and Tube Wiring:

- Oldest type of wiring, installed in homes before the 1950s.
- Consists of uninsulated copper wires run through porcelain insulators attached to wooden knobs.
- Considered outdated and unsafe due to its susceptibility to electrical fires.

2. BX/Armored Cable Wiring:

- Introduced in the 1920s, known as "Romex" or "BX."
- Features two or three insulated conductors wrapped in a protective metal armor.
- Flexible and easy to install, but must be secured properly to prevent damage.

3. NM (Non-Metallic) Cable Wiring:

- Most common type of wiring used in modern homes.
- Consists of insulated conductors enclosed in a non-metallic sheath.
- Flexible, durable, and resistant to moisture, making it suitable for indoor and outdoor use.

4. UF (Underground Feeder) Cable Wiring:

- Designed for direct burial underground.
- Features insulated conductors wrapped in a moisture-resistant jacket.
- Used to connect electrical panels to outdoor lighting, appliances, and other devices.

5. MC (Metal Clad) Cable Wiring:

- Similar to BX but features a corrugated metal sheath that provides additional protection.
- Flexible and durable, suitable for both surface mount and concealed installations.
- Often used in commercial and industrial applications.

6. THHN (Thermoplastic High-Heat Resistant Nylon) Wire:

- Type of individual insulated wire used for specific applications, such as lighting fixtures and electrical panels.
- Heat-resistant and flame-retardant, suitable for high-temperature environments.
- Typically used in conjunction with conduit or other protective measures.