Connectors and Cables
Solar panels originally came with a junction box (JBox) that needed
individual wires to be attached to connect them together. This made
installation very time-consuming, so pre-installed quick connect cables
and plugs were developed, and these have replaced the junction box
only modules. Changes in the NEC code now require the use of locking
connectors in publicly accessible locations. The most common locking
connector is the Multi-Contact MC4. Others are the Amphenol H4, SMK,
and the TE Connectivity connectors. The NEC code also introduced new
wire insulation requirements for use with ungrounded PV arrays (Source
Circuits) when wires are not run in conduit or wire raceways. The new
PV-Wire specification requires that the conductor must be listed to UL
Standard 4703. Ungrounded arrays are arrays that do not have a ground
fault fuse tying one of the source conductors to ground. This is typically
found in the new āTransformerlessā range of inverters. Most module
manufacturers are now supplying their
products with locking connectors and PV-Wire
to comply with the new standards.