Electrical Wiring Services

Raceways & Conductors

The raceway & conductor installation method is commercial facilities’ most common electrical wiring type. This installation type involves an enclosed metallic or nonmetallic conduit that holds electrical wires. Commercial wiring typically consists of copper or aluminum conductors, PVC insulation, and a protective layer like a thermoplastic high heat-resistant nylon jacket (THHN) or a thermoplastic heat and water-resistant nylon jacket (THWN).

Most Common Types of Raceways & Conductors

Popular types of raceways and conductors in commercial buildings include:

• RMC, or rigid metal conduit, is a thick, zinc-coated conduit of galvanized steel. It works best for heavy-duty applications requiring high levels of protection from physical damage.
• IMC, or intermediate metal conduit, has a thinner wall than the RMC. It includes a corrosion-resistant inner coat, and an exterior galvanized layer.
• FMC, or flexible metal conduit, consists of a self-interlocked metal coil that offers high flexibility and durability.
• EMT, or electrical metallic tubing, is the most common raceway in construction because its durability and economical thin-wall tubing can protect wires from moisture, chemicals, and impact.
• PVC, or polyvinyl chloride conduits, is popular for underground or concrete-encased applications.

Advantages of Raceways & Conductors

The raceways & conductors wiring offers several advantages, including:

• Excellent protection from physical damage
• Some flexibility in circuit installation
• An inexpensive solution for underground wiring
• Raceways can be used in remodeling work

Disadvantages of Raceways & Conductors

On the other hand, this method also has its cons, such as:

• Installation costs are typically higher
• Often, a more complex installation than cabling systems
• Limited applications for PVC conduits
• High installation costs in some applications
• A limited number of bends is allowed before a junction box is needed

Busways

Busways are another type of commercial wiring. Also known as a bus duct, busways are a metal-enclosed raceway consisting of pre-mounted bus bars. There are two types of commercial busways: plug-in style and feeder style, and they can be configured with insulated or bare conductors.

Advantages of Using Busways

Busways offer several advantages over their wiring counterparts, including:

• Have a large ampere rating availability (60-4,000 Amps)
• There’s less impact from total voltage drop
• Have a compact size compared to conduits, making it a cost-effective option
• Plug-in busways have the flexibility to add and change load take-offs

Disadvantages of Using Busways

Busways also come with some drawbacks, such as:

• High installation costs if the system requires many offsets and elbows
• Not suitable for areas subject to potential physical damage
• Vulnerability to water leaks
• Limited space for bus plugs in vertical applications
• High short-circuit current available on busways

Cable Assemblies

Manufactured cable assemblies typically consist of multiple neutral and insulated-phase conductors and a grounding conductor wrapped in a metal or non-metal sheath. Standard assemblies are typically equipped with THHN/THWN conductors. A manufactured cable assembly can be a standard product or custom ordered with specific conductor configurations.

Most Common Types of Cable Assemblies

The most common commercial cable assemblies include:

• AC (armored cable) – an aluminum- or steel-sheathed cabling type often used in commercial and industrial projects for branch wiring between luminaires and electrical outlets.
• MC (metal-clad cable) – a low-voltage, in-ground method suitable for dry-conduit or direct burial installations. Wet and direct burial locations require a PVC jacket.
• MI (mineral-insulated cable) – a cable that includes a seamless copper conductor with a magnesium oxide coating. This setup works well for high-performance electric utility systems.
• NM, NMC, or NMS (nonmetallic sheathed cabling) – a conductor set with a non-metal sheath typically used in light commercial applications and household-type constructions.
• SE or USE (service entrance cable) – a non-metallic-sheath conductor set in a PVC jacket. This installation type is suitable for crawl spaces, attics, and other locations where the wiring usually doesn’t withstand much physical damage.
• UF (underground feeder) – a cabling kit that works best for underground wiring systems that need to withstand rough conditions

Advantages of Using Cable Assemblies

Cable assemblies offer benefits including:

• Comparatively low installation costs
• Quick installation with unlimited bends
• Factory-testing for performance and safety
• Mineral-insulated cable is fire-resistant for up to 30 minutes

Disadvantages of using Cable Assemblies

There are disadvantages of cable assemblies, just like with any cable option, including:

• The need for shorter-spaced support
• Typically, lower resistance to physical damage
• No post-installation upgrade options
• Requires a special abandonment process
• Cannot be installed in locations where they could be subjected to physical damage
• Extreme planning is involved during cable procurement