PV conductors must be contained in metal conduit when they are located in hazardous or corrosive environments to ensure maximum safety and protection.

When Must PV Conductors be Contained in Metal Conduit?

Photovoltaic (PV) systems have become increasingly popular in recent years due to the growing demand for renewable energy sources. These systems generate electricity using solar panels that convert sunlight into direct current (DC) electricity. However, just like any electrical system, PV installations need to adhere to safety guidelines to prevent accidents and ensure proper functioning. One crucial aspect of PV installations that is often debated is whether the conductors need to be contained in metal conduits. In this article, we will explore when and why PV conductors must be contained in metal conduit.

Safety is of utmost importance when it comes to electrical installations. PV systems involve high DC voltages, which require careful handling and protection to avoid electrical shock hazards. The National Electrical Code (NEC) provides a set of safety regulations to ensure the proper installation of electrical systems, including PV installations. These guidelines are crucial to protect both the system and the individuals working on or around it.

Section 690.31(A) of the NEC states that all PV system conductors that are installed more than 7.5 feet above finished grade or working surfaces must be contained in a grounded metal conduit. This requirement aims to prevent the possibility of accidental contact with live conductors, which could result in electric shock or electrocution. By enclosing the conductors within a metal conduit, any fault in the system will be contained within the conduit, minimizing the risk of injury to personnel and damage to property.

In areas where PV conductors are not required to be in metal conduit, they can be installed in non-metallic conduit (such as PVC) or even in direct burial if specific conditions are met. However, it is essential to remember that these conductors should still comply with the NEC regulations regarding sizing, insulation, and protection against mechanical damage.

The requirement for metal conduit containment applies primarily to PV systems installed on rooftops or other elevated structures. This is because installing the conductors above the 7.5 feet height threshold brings them within reach of individuals and requires additional protection against accidental contact. On the other hand, PV systems installed on the ground or in open areas are not subject to the same height restrictions, and the conductors can be installed differently. The NEC does not mandate metal conduit containment for ground-mounted systems, allowing for other types of installations, such as using direct burial or non-metallic conduit.

One aspect that may influence the need for metal conduit containment is the presence of other equipment or conductors near the PV system. If there are electrical service conductors, communication lines, or other power sources nearby, it is crucial to evaluate the potential for interaction or interference. In such cases, it is recommended to contain the PV conductors in metal conduit to minimize the risk of issues like induced voltages or electromagnetic interference.

It is essential to note that metal conduit is not the only solution for containing PV conductors on rooftops. Section 690.31(C) of the NEC allows other methods if they offer equivalent protection. This includes the use of continuous raceways made of insulating material or the application of conductive metal tape or non-metallic tape over the conductors spaced at intervals not exceeding 900 mm (3 feet).

In conclusion, the requirement for PV conductors to be contained in metal conduit applies when the conductors are installed more than 7.5 feet above finished grade or working surfaces. This regulation aims to ensure the safety of personnel working on or around the system, protecting them from accidental contact with live conductors. However, the National Electrical Code provides alternative solutions if they offer equivalent protection, such as the use of continuous insulated raceways or conductive tape. Ultimately, following these guidelines will help to ensure the safe and efficient operation of PV systems while minimizing the risks associated with high DC voltages.