334.10 Nonmetallic-Sheathed Cable. Devices of Insulating Material.
Code Change Summary: A clarification was made to restrict the use of nonmetallic sheathed cable interconnector devices. Also, any switches or receptacles installed without a box must be of the self-contained type.
The NEC® generally requires newer wiring methods to be spliced in a junction box and the wiring in the box to be accessible without the need to remove part of the building or structure (see 300.15 and 314.29). Section 300.15(H) refers to Section 334.40(B) when splicing nonmetallic sheathed cable (NM, NMC, NMS) and allows a special insulated device to be used instead of a splice box.
The previous code language in 334.40(B) did not require these special insulating devices to be listed by a nationally recognized testing lab (NRTL) and also allowed them to be concealed when rewiring an existing building.
Now, the 2014 NEC® makes it clear that these splicing devices must be listed by a NRTL (such as UL) and can only be used without a box as follows:
- If installing new cable wiring, the splicing device must be exposed.
- If repairing wiring in an existing building, the splicing device can be concealed.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on the “free access” tab and select the applicable year of NFPA 70 (National Electrical code).
2011 Code language:
334.40(B) Devices of Insulating Material. Switch, outlet, and tap devices of insulating material shall be permitted to be used without boxes in exposed cable wiring and for rewiring in existing buildings where the cable is concealed and fished. Openings in such devices shall form a close fit around the outer covering of the cable, and the device shall fully enclose the part of the cable from which any part of the covering has been removed. Where connections to conductors are by binding-screw terminals, there shall be available as many terminals as conductors.
2014 Code Language:
334.40(B) Devices of Insulating Material. Self-contained switches, self-contained receptacles, and nonmetallic-sheathed cable interconnector devices of insulating material that are listed shall be permitted to be used without boxes in exposed cable wiring and for repair wiring in existing buildings where the cable is concealed. Openings in such devices shall form a close fit around the outer covering of the cable, and the device shall fully enclose the part of the cable from which any part of the covering has been removed. Where connections to conductors are by binding-screw terminals, there shall be available as many terminals as conductors.
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334.10 Nonmetallic-Sheathed Cable. Devices of Insulating Material.
Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:Which of the following can be used without a box when terminating nonmetallic sheathed cables?
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