You use a junction box to route cables, create splices, and terminate connectors safely while keeping wiring tidy and serviceable. Learn what the NEC requires for junction boxes, from box fill calculations and grounding to outdoor use and fire-rated wall installations. Though small, this box plays a vital role in protecting circuits from damage, simplifying maintenance, and preventing electrical. Pull boxes, junction boxes, and conduit bodies must be sized to allow conductors 4 AWG and larger to be installed without damage to the conductor insulation. The NEC provides sizing requirements in 314.
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