Generally, running Schedule 40 PVC conduit on the bottom of floor joists in an unfinished basement is permissible, but there are crucial considerations and potential code requirements that must be taken into account. Here's a breakdown

Pros and Considerations:
Protection

PVC conduit offers good physical protection to the conductors.

Ease of Installation

PVC is relatively easy to cut, assemble, and support.

Cost-Effective

PVC is often a more economical option compared to metal conduit.

Moisture Resistance

Basements can be damp, and PVC is highly resistant to moisture.

Cons and Requirements



Local Codes and Amendments

The National Electrical Code (NEC) is a minimum standard. Your local jurisdiction (city, county, or state) may have amendments or more restrictive rules that supersede the NEC. Always check with your local building and electrical inspectors.

Physical Damage

PVC is more susceptible to physical damage than metal conduit (like EMT or rigid). If the area is prone to impacts (e.g., heavy storage, work area), you might need to consider metal conduit or additional protection.

Support

The conduit must be properly supported at intervals specified by the NEC (typically every 3 feet for smaller sizes). Proper supports prevent sagging, which could stress the conduit and conductors. The use of appropriate clamps or straps is essential.

Conductor Fill

Ensure you don't exceed the permitted conductor fill for the size of the PVC conduit. Overfilling can lead to overheating and is a code violation.

Derating

If you have multiple current-carrying conductors in the same conduit, you may need to derate the ampacity of the conductors to prevent overheating.

Grounding

Ensure proper grounding of the electrical system. While PVC conduit itself doesn't provide a grounding path, the grounding conductor must be run inside the conduit with the circuit conductors.

Proper Fittings

Use only fittings that are specifically designed for use with PVC conduit. Solvent-weld (glue) the fittings properly to ensure a watertight and secure connection.

Professional Advice

When in doubt, it is always best to consult a qualified electrician for guidance and installation.

Fused Conductors

The fact that the conductors are "fused" is less relevant to the method of running the conduit and more related to circuit protection. Fuses or circuit breakers are required to protect the conductors from overcurrent. Make sure the fuse/breaker size is appropriate for the ampacity of the conductors and the connected load.

In Summary

While running Schedule 40 PVC on the bottom of floor joists in an unfinished basement can be acceptable, it's critical to:1.

Check local codes and obtain permits if required.2. Properly support the conduit.3. Use appropriate fittings and connections.4. Adhere to conductor fill and derating requirements.5. Ensure proper grounding.6. Protect the conduit from physical damage if necessary.7. When in doubt, consult a qualified electrician.

Ignoring these considerations could result in code violations, safety hazards, and potential electrical problems. Flag for review