PVC (Polyvinyl Chloride) rigid conduit is one of the most popular materials used in electrical installations. PVC rigid conduit is known for its durability, versatility, and cost-effectiveness.
While PVC rigid conduit is highly durable, the effectiveness of the system depends on proper installation techniques. Incorrectly installed conduit can lead to a range of issues, from electrical hazards to system failures. Moreover, improper installation can result in breaches in electrical codes.
1. Tools and Materials Required
Before beginning any PVC rigid conduit installation, it's essential to gather the appropriate tools and materials.
1.1 Essential Tools for Installation
- Measuring Tape and Marker/Pencil
A measuring tape will help determine the correct length, while a marker or pencil is used to mark where the cuts should be made.
- Tools for Cutting & Bending Conduit
Hacksaw: A hacksaw is commonly used to cut PVC rigid conduit. Its fine-toothed blade allows for precise cuts.
PVC Pipe Cutter: For faster and cleaner cuts, a PVC pipe cutter can be used as an alternative to a hacksaw.
Conduit bender: If bends are required, a conduit bender designed for PVC helps create smooth, controlled angles without damaging the conduit.
- Deburring Tool
A deburring tool smooths out these sharp edges. Burrs can damage the insulation on electrical wires as they’re pulled through the conduit. Over time, damaged insulation can cause electrical shorts, system malfunctions, or even fire hazards.
- Level and Fish Tape
A level is important to ensure that conduit runs are straight and properly aligned.
Fish tape allows you to feed the tape through the conduit, attach the wires, and then pull them through, simplifying the wiring process.
- Personal Protective Equipment (PPE)
Safety glasses, gloves, and a dust mask are necessary to protect yourself from debris and sharp edges during cutting and handling the conduit.
1.2 Necessary Materials for Installation
- PVC Rigid Conduit
The main material for the installation, PVC rigid conduit, comes in various sizes depending on the electrical wires being protected.
- Conduit Fittings
Conduit fittings are crucial for facilitating wires' smooth and organized routing in PVC rigid conduit systems.
- Solvent Cement
Solvent Cement: Used to join sections of conduit and fittings together. The cement creates a strong, chemical bond, ensuring a watertight and secure connection.
- Electrical Tape and Pulling Lubricant
Electrical Tape: Bundles wires together and provides protection while pulling them through the conduit.
Pulling Lubricant: Reduces friction when pulling wires through long or complex conduit runs, making the process easier and minimizing the risk of wire damage.
2. Tips Selecting the Right Conduit for the Job
One of the most important considerations when installing conduit is ensuring that the size of the conduit can adequately accommodate the wires you plan to run. Conduit size must allow enough space. Overfilling conduit can result in overheating, making the system unsafe.
2.1 PVC Rigid Conduit Types Choosing
It’s important to consider the specific requirements of the installation environment when choosing conduit.
- Environmental Factors: For outdoor installations, UV-resistant, solar conduit may be a good choice. Ctube's solar conduit has been upgraded with enhanced PVC material, specially designed to withstand strong UV rays for improved durability and performance in outdoor environments. While conduit installed in underground or wet locations may require high level of waterproof.
- Temperature Variations: For areas subject to extreme temperatures, choose conduit that can withstand both high and low-temperature conditions without cracking or warping.
- Physical Impact: If the conduit is likely to be exposed to physical impact or mechanical stress, use a more rigid type of PVC conduit such as Schedule 40 or 80. Like Ctube’s SCH 40 & 80 certified by UL listed guarantees high quality and reliability for your project.
2.2 PVC Rigid Conduit Sizes Choosing
The National Electrical Code (NEC) provides guidance on the maximum allowable wire fill for different conduit sizes.
- One wire: The fill should not exceed 53% of the conduit’s internal cross-sectional area.
- Two wires: The fill should not exceed 31%.
- Three or more wires: The fill should not exceed 40%.
3. Introduction to Conduit Fittings
3.1 What are Conduit Fittings?
Conduit fittings ensure that conduits remain securely fastened, aligned, and organized, minimize physical strain on wires, and make future access easier for maintenance and repair.
They are also vital for ensuring the system's integrity by providing watertight and secure connections, especially in outdoor or underground installations where exposure to moisture or environmental elements is a concern.
3.2 Common Types of PVC Conduit Fittings
- Couplings: To Join Two Pieces of Conduit
Couplings are simple yet vital fittings used to join two sections of PVC conduit together in a straight line. They ensure a seamless connection, maintaining the alignment of the conduit runs and providing a strong, watertight bond when used with PVC solvent cement.
- Elbows/Sweep Bend: For Making Turns or Bends in the Conduit System
Sweep bends offer a gentle, gradual curve that’s better for long runs and reducing wire strain, while elbows provide a more compact, sharper turn for tighter spaces. Typically at 90-degree or 45-degree angles. Ctube also offer 22.5 -degree angles elbows.
Understanding the difference between these two types of fittings will help you choose the right one for your specific installation needs.
- Tee Connectors: For Branching the Conduit into Multiple Directions
The tee connector forms a "T" shape. They allow a single conduit run to split into two or more directions. , with the main conduit passing through the horizontal section, and the vertical outlet providing a path for the new branch.
- Adapters: For Connecting PVC Conduit to Boxes or Different Conduit Types
Male Adapters and Female adapter are used to connect PVC conduit to other system components. For example, a male adapter might be used to connect a PVC conduit to a electrical box, providing a secure transition between the two electrical elements.
- Electrical boxes: Housing Electrical Wiring for Safety
These boxes safeguard wiring from external damage, moisture, and debris, ensuring that electrical components are housed securely and remain accessible for future maintenance or modifications. Electrical boxes come in various types, including junction boxes for connecting multiple conduits and adaptable boxes that allow flexibility in installation and future expansion.
4. Preparing for Installation
Before starting the installation of PVC rigid conduit, it’s essential to properly plan and prepare to ensure an efficient, code-compliant, and safe electrical system.
4.1 Planning the Conduit Layout
One of the first steps is mapping out the conduit system to create an efficient layout. This reduces the complexity of the system, such as minimizing bends to reduce stress on both the wires and the conduit over time and confirming the length of the conduit to avoid excessive waste.
Before starting any installation, it’s essential to review local electrical codes, such as the NEC (National Electrical Code) in the U.S., to ensure compliance with regulatory standards. Non-compliance with electrical codes can result in unsafe installations or costly rework. Key aspects to consider include:
- Maximum distance between pull points (boxes or junctions).
- The total number of bends allowed between pull points.
- The correct support and spacing for conduit sections.
4.2 Cutting or Bending PVC Rigid Conduit (if needed)
Since we have already introduced the tools at the beginning, let's start using the tools for cutting and bending conduit operations.
Measure and Mark: Before cutting, use a measuring tape to determine the exact length of conduit you need. Mark the cutting line clearly with a pencil or marker.
Secure the Conduit: To avoid movement while cutting, secure the conduit with a clamp or in a vise. This ensures that the cut is straight and precise.
Cut Along the Marked Line: Whether using a hacksaw or a pipe cutter, cut along the line you’ve marked, ensuring steady, consistent pressure as you cut through the conduit.
Deburring the Edges: Use the deburring tool, the specially designed deburring tool has a curved blade that easily scrapes away burrs from the inside and outside edges of the conduit. Simply run the tool around the cut edges of the conduit, ensuring the surface becomes smooth and even.
Check for Smoothness: Once deburred, check the surface by running your finger gently along the edge. It should feel smooth and free of any sharp points.
Bending PVC rigid conduit is sometimes necessary to create an efficient layout or navigate obstacles. To do this, you'll need a heat gun, a bending jig or template, thermal gloves, and basic tools like a measuring tape and marker. The process involves heating the conduit evenly with a heat gun until it's soft and flexible, then gently bending it around the jig or guide and holding it in place until it cools. It's important to maintain a proper bend radius to protect the wires inside, prevent damage, and ensure compliance with electrical codes.
5. Joining PVC Rigid Conduit with Solvent Cement
5.1 Choosing the Right Solvent Cement
When selecting solvent cement for PVC rigid conduit, it's important to choose based on conduit size and installation conditions. Regular-bodied cement works well for small-diameter conduits (up to 2 inches), medium-bodied is suitable for medium-diameter conduits (up to 6 inches), and heavy-bodied cement is ideal for larger conduits and more demanding applications like underground or high-pressure systems. Additionally, factors such as conduit size, environmental conditions (e.g., extreme temperatures, moisture), and curing time should be considered to ensure optimal bonding and performance.
5.2 Applying Solvent Cement
Before applying the solvent cement, the surfaces of both the conduit and the fitting must be clean and free of debris.
Using the applicator brush provided with the solvent cement, apply a generous, even coat of cement to the outside end of the conduit. Next, apply a thinner coat of solvent cement to the inside of the fitting. This coat should be slightly less thick than the one applied to the conduit but should still cover the entire bonding surface.
5.3 Making the Connection
Hold the conduit and the fitting in a straight line. Insert the conduit into the fitting. Push the conduit firmly into the fitting with a slight twisting motion (about a quarter-turn).
Once the conduit is fully inserted into the fitting, hold it in place for 10-15 seconds.
Solvent cement requires time to fully cure.
5.4 Fixing of Rigid Conduit
Fixing electrical conduits involves securely attaching the conduit to surfaces using mounts or fittings to ensure a stable and safe installation. Common methods include using conduit clamps, brackets, or straps, which are typically fastened to walls, ceilings, or other structural elements with screws or anchors.
6. Pulling Wires Through the Conduit
Before pulling wires through the conduit, it's crucial to organize them to ensure a smooth process and use fish tape.
6.1 Preparing the Wires
Start by grouping wires based on their purpose, such as power, lighting, or communication, and label them with tags or colored tape for easy identification during installation and final connections. Measure the conduit run and cut the wires slightly longer than needed to allow for secure connections at both ends. Straighten the wires to prevent tangling, and for longer or complex runs with multiple bends, consider using a wire-pulling lubricant to reduce friction and make the pulling process easier.
6.2 Using a Fish Tape
First insert the fish tape into one end of the conduit, carefully pushing it through until it reaches the other side. Once the fish tape emerges, securely attach the wires to the loop at the end of the tape using electrical tape to create a smooth connection. Next, pull the fish tape back through the conduit, slowly drawing the wires with it.
7. Final Checks and Testing
After completing the installation, it’s essential to perform thorough final checks to ensure everything is properly installed and meets electrical safety standards.
8. Conclusion
The successful installation of PVC rigid conduit requires careful planning, accurate cutting, and proper joining techniques, with the use of appropriate fittings and tools. Adhering to safety standards and electrical codes throughout the process is critical for both performance and compliance.
