590.4(G) Splices.
Code Change Summary: New exception 2 provides special allowances when installing temporary power or lighting on construction sites.
In the 2020 NEC®, temporary construction power and lighting will be given special treatment when it comes to open boxes containing live splices and using permanently installed wiring methods recessed behind wall and ceiling finishes.
As sheetrock ceilings go up, temporary construction lighting in the rafters must come down, leaving the work area in the dark while tripod lights are brought in. Then there is a waiting game involving the inspector and the power company until permanent power is approved and energized.
In the 2020 NEC®, language was added to allow the permanently installed wiring and boxes behind wall and ceiling finishes to be used to provide construction power and lighting as long as certain conditions are met. This will allow permanently installed ceiling boxes to have listed pigtail-type lampholders installed temporarily for lighting until permanent fixtures are installed.
Part of the new language allows certain boxes containing splices to be without a cover which makes easier for both the electrician and the painter who seem to fight back and forth to cover and uncover the boxes during the painting process.
If a touch-safe pigtail such as snap-in switches and receptacles are to be used, the new language will allow a box containing live conductors spliced to a finger-safe device to go without a cover plate during construction.
Everything in the new exception revolves around branch-circuits that are permanently installed in framed walls and ceilings and are used to supply temporary power or lighting, and that are GFCI protected.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
590.4(G) Splices. A box, conduit body, or other enclosure, with a cover installed, shall be required for all splices except where:
(1) The circuit conductors being spliced are all from nonmetallic multiconductor cord or cable assemblies, provided that the equipment grounding continuity is maintained with or without the box.
(2) The circuit conductors being spliced are all from metal sheathed cable assemblies terminated in listed fittings that mechanically secure the cable sheath to maintain effective electrical continuity.
2020 Code Language:
590.4(G) Splices. A box, conduit body, or other enclosure, with a cover installed, shall be required for all splices.
Exception No. 1: On construction sites, a box, conduit body, or other enclosure shall not be required for either of the following conditions:
(1) The circuit conductors being spliced are all from nonmetallic multiconductor cord or cable assemblies, provided that the equipment grounding continuity is maintained with or without the box.
(2) The circuit conductors being spliced are all from metal-sheathed cable assemblies terminated in listed fittings that mechanically secure the cable sheath to maintain effective electrical continuity.
Exception No. 2: On construction sites, branch-circuits that are permanently installed in framed walls and ceilings and are used to supply temporary power or lighting, and that are GFCI protected, the following shall be permitted:
(1) A box cover shall not be required for splices installed completely inside of junction boxes with plaster rings.
(2) Listed pigtail-type lampholders shall be permitted to be installed in ceiling-mounted junction boxes with plaster rings.
(3) Finger safe devices shall be permitted for supplying and connection of devices.