Electrical wiring is what brings power to your home, office, or shop. It carries electricity to your outlets, switches, and appliances.
It’s important to know the different types of wiring. This knowledge is useful when building a new structure. It also helps when planning a remodel or updating old systems.
This guide explains the most common types of electrical wiring. It shows where each type is used, what it’s made of, and why one kind may be better than another in certain areas.
Key Takeaways
- Different wiring types exist for different uses, such as indoors, outdoors, or underground.
- Choosing the wrong wire can cause safety issues or fail to meet building code.
- Non-metallic cable is the most common type of residential wiring.
- Older systems like knob and tube wiring are dangerous and should be replaced.
- Always consult a licensed electrician before rewiring.
Why Wiring Type Matters
Each type of electrical wiring has a job. Some are better for dry indoor spaces. Others are made to handle moisture, movement, or heat.
The wiring type affects how safe and efficient the electrical system is. It also impacts whether your setup follows the National Electric Code.
For new builds, remodels, or upgrades, knowing which wire to use means fewer problems down the line. It also helps electricians complete jobs faster and pass inspections.
Common Electrical Wiring Types Explained
Many homes use more than one type of electrical wire. Each type is built for a specific purpose and location.
Non-Metallic (NM) Cable (e.g., Romex)
This is the most common type of residential wiring. It includes two or more insulated wires and a bare ground wire. All are wrapped in a plastic sheath.
NM cable is used inside walls, ceilings, and floors. It’s color coded based on the gauge wire inside. For example, yellow often means 12-gauge wire for 20-amp circuits.
Pros: Easy to run, cheap, flexible.
Cons: Not for outdoor or exposed use.
Armored Cable (AC)
AC cable is also called BX cable. It has a metal sheath around the insulated wiring inside. That metal casing protects it from cuts and damage.
AC is used in older buildings or areas with higher risk of impact. It takes longer to install because it needs special tools and connectors.
Pros: Strong, protective.
Cons: Heavier, harder to install.
Underground Feeder (UF) Cable
This is a type of wiring similar to NM but made for outdoor use. It has a solid plastic sheath that resists water and sunlight.
UF cable is buried directly in soil without needing a conduit. It’s often used for outdoor lighting, garages, or sheds.
Pros: Waterproof, durable.
Cons: Harder to strip and bend.
Metal-Clad (MC) Cable
MC cable looks like armored cable but is more flexible. It includes an insulated hot wire, neutral wire, and a grounding conductor. All are wrapped in a metal casing.
MC is used in commercial and industrial spaces. It works well in damp areas and can be used without conduit.
Pros: Flexible, code-approved for many environments.
Cons: Slightly more expensive than NM.
Low-Voltage Wiring
This type of wiring carries 50 volts or less. It’s used for doorbells, thermostats, and landscape lighting.
Low-voltage systems don’t follow the same wiring rules as standard 120 volts wiring. They use smaller gauge wire and different connectors.
Pros: Safe, easy to install.
Cons: Limited power, not for outlets or large fixtures.
Coaxial, Ethernet, and Other Communication Cables
These wires don’t carry high-voltage power. They’re used for phones, internet, and cable TV. Most are low-voltage and follow different codes from regular electrical wires.
Poor installation can lead to weak signals or damage to equipment. These wires may also need to be shielded or separated from power lines to prevent interference.
Wiring That Should Be Replaced: Knob and Tube (K&T) Wiring
Knob and tube wiring was common in homes built between 1880 and 1940. It runs individual wires through ceramic knobs and tubes.
K&T lacks a ground wire, which makes it unsafe by modern standards. It also becomes brittle over time, and its insulation can fail. If someone added insulation in the attic or walls, the fire risk goes up.
Insurance companies often won’t cover homes with K&T wiring. It’s best to remove it during any upgrade or remodel.
Summary:
- No ground wire
- Prone to damage
- High fire risk
- Often uninsurable
- Should be replaced with modern insulated wiring
Factors to Consider When Choosing Wiring
Choosing the right wire means looking at more than cost.
Here’s what to check:
- Local Codes: Not all wiring types are legal in every area.
- Location: Use weather-resistant wire for outdoor or damp spaces.
- Load: Know how much electricity the wire needs to carry.
- Flexibility: Some wires are easier to bend around corners.
- Protection: Use armored cable in areas with high risk of impact.
- Grounding: Some wires come with a built-in ground wire. Others don’t.
Trust Right Touch Electrical for Whole House Rewiring
Wiring isn’t a DIY job. A wrong connection or exposed hot wire can start a fire or cause shock. It can also void your insurance or fail inspection.
Right Touch Electrical does full rewiring jobs in Houston, TX, and nearby areas. Their licensed electricians follow the National Electric Code. They work fast, clean, and right the first time.
They use high-quality insulated wiring and plan each job carefully. Their slogan is “quality with a master’s touch,” and they mean it.
If your home has knob and tube wiring or any outdated system, give them a call. They’ll inspect, quote, and get the job done safely.
FAQs About Types of Electrical Wiring
If you still have questions, this section covers the most common ones. These answers are short and direct, based on current best practices.
What is the most common type of residential wiring?
Non-metallic (NM) cable, also called Romex. It’s used in most indoor walls and ceilings.
Can NM cable be used outdoors?
No. Use UF cable or a conduit system for outdoor work.
What’s the difference between AC and MC cable?
Both have metal sheathing. MC is more flexible and has a grounding conductor. AC may not have a ground wire.
What type of wiring is used for underground projects?
Underground Feeder (UF) cable. It’s made for direct burial.
Is knob and tube wiring still safe?
No. It lacks a ground wire and fails under modern standards.
What gauge wire should I use?
It depends on the load. For a standard 15-amp circuit, 14-gauge wire is common. For 20-amp, use 12-gauge.
Are communication wires like Ethernet regulated the same as power wires?
No. They follow different rules and carry much lower voltage.
Final Thoughts
Choosing the right wiring type is about safety, function, and following the rules. Don’t just pick what’s cheapest or easiest. Think about where the wire goes, how much current it will carry, and what risks are present.
Always check local codes, and always consult a professional. If you’re in Houston, Right Touch Electrical has you covered. They deliver “quality with a master’s touch,” and they don’t cut corners.
When in doubt, don’t guess. Use the right wire for the job.
