Wiring practices

Wire is used to connect all of the parts of a PV system. For wires to function safely and for an installation to last, it is vital that all wiring is installed according to its appropriate conditions of use and that it is protected against damage. One small error - loose wire strands at a connection creating a fault, a wire rubbing against the corner of a metal roof, insulation inserted into a connection - can lead to a system malfunction and potentially a fire. The following are some good installation practices that can help prevent system issues:

1. If exposed to physical damage, a wire should be protected by some type of conduit or should be relocated. Physical damage can result from contact from persons, animals or the enviroment. This also depends upon the type of wire as some wires and cables permit installation in wet loations or exposed to the sun.
2. All wires should have extra length left in junction boxes or at any point where a connection is made. This serves several important purposes:

• To prevent damage from the accidental contact with a person that may move the wire. An overly tight wire exposed to tension may immediately break free from its connection and cause a fault or fire.
• To allow for expansion and contraction of wire and conduit resulting from heating and cooling.
• To provide extra wire that enables safe working conditions in the future.

1. All connections made with wire should be done with some kind of mechanical connection, like a wirenut, busbar or PV module connector. Connections performed solely with electrical tape - as is common practice in many parts of the world - are far more likely to fail and cause issues.
2. All wires that are entering a connection (busbar, should leave some copper exposed to ensure that insulation is not entering the connection. Insulation in a connection can create resistance, heat and ultimately a fire.

• Labeling wires at all connections.
• No sharp bends.