PV wire, Also known as photovoltaic cable, it is a single core wire used to connect photovoltaic power system panels. A photovoltaic system or solar panel is an electricity production system that captures sunlight to generate electricity through an energy conversion process. Electricity is generated on the panel and requires PV wires to transmit and recycle the electrical energy to collection points or devices. PV wire is a specific type of wire created for photovoltaic applications.
NEC (Electrical Code) has established Article 690 for solar photovoltaic (PV) systems to guide the electrical energy systems, array circuits, inverters, and charging controllers of photovoltaic systems. NEC is commonly used in various installations in the United States (which may be subject to local regulations).
Article 690, Part IV of the 2017 NEC allows for various wiring methods in photovoltaic systems. For single conductors, UL listed USE-2 (underground service entrance) and PV cable types allow for exposed outdoor locations of PV source circuits within the PV array.
Photovoltaic lines are also allowed to be installed in trays for outdoor photovoltaic source circuits and photovoltaic output circuits without the need for rating tray usage. If the PV source and output circuit operate at voltages exceeding 30 volts in accessible locations, there are indeed limitations. In these cases, MC type or suitable conductors need to be installed in the raceway.
NEC does not recognize Canadian type names, such as RWU90 cables, RPV cables, or RPVU cables used for solar applications, which do not include suitable dual UL lists. For installations in Canada, Section 64-210 of the 2012 CEC provides information on the types of wiring allowed for photovoltaic applications.
Advantages of photovoltaics
PV modules operate at high temperatures and are exposed to various environmental conditions. NEC restricts various PV array applications to USE-2 or PV lines. These cables need to meet the required sun resistance and temperature ratings for the environment.
PV wire are manufactured for photovoltaic applications, while USE-2 cable types are typically manufactured for underground service entrance applications. These two types of cables usually contain XLPE insulation material and can resist sunlight and/or be directly buried.
PV cable differ from USE-2 wires in terms of insulation thickness, rated voltage, and operating temperature. The PV line contains a thick insulation layer, which is suitable for withstanding various harsh environments. The rated voltage of USE-2 is as high as 600 V, while the PV cable provides three rated voltages: 600 V, 1 kV, and 2 kV. The higher operating temperature of the USE-2 cable type is 90 º C, while PV wire can withstand higher temperatures.
PV wire is one of the few single wire types with a rated voltage exceeding 600 V and directly buried without shielding according to NEC.
