The DC wiring of a conventional PV installation uses a relatively large number of terminals. In such cases, incorrect wiring can disable an entire string or even cause arcing and a fire. Hence only quality terminals should be used, and wherever possible ones that integrate elements that prevent wires from coming loose. Terminals without springs should be checked periodically for loose connections and should be tightened if necessary (copper is subject to creep under stress). The cables and wires should be mechanically fastened down via suitable fittings or the like so that in the event of a wire coming loose it will not touch another terminal or the housing.
126.96.36.199.2 Disconnect Terminals
Disconnect terminals should only be touched while in a currentless state and should never be used to switch direct current, as this could cause arcing.