NM Romex Jacket in Panel

Wondering what the actual rules are for NM cable in a service panel still having its outside jacketing intact.

What is the concern with having this jacketing on the wire inside the panel?

I believe the only ‘rule’ is:
(e) Each cable sheath extends not less than ¼ in. into the panel board.

Now, when I see it in a panel it suggests to me that work was done by a ‘non-professional’. Note the missing clamp where the NM enters at the base.

Correct. There is no maximum.

I’d be more concerned about the missing grommet/bushing.

There is no minimum either. :smiley:

Do you mean as long as the sheathing jacket is clamped into the connector?

Ugly, but not a problem. Its not hurting anything.

What connector are you referring to?

Yes, the 1/4" rule is for nonmetallic boxes.

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Not less than 1/4" correct?

Good catch.

Sticking your fingers into service panels is not advised… you have no idea if all wiring was properly stripped at installation. I’ve seen many instances of damaged wiring insulation leaving exposed conductors.

Yes, not less than 1/4" for certain nonmetallic boxes. Here’s the NEC section:

This, Roy, what Robert answered later:

The flip side is that the NEC also requires 6 " or more of free conductor outside the sheath.

Yep and the rule also applies to metallic boxes as well now in the 2017 NEC.

314.17(B) Metal Boxes and Conduit Bodies. Where metal boxes or
conduit bodies are installed with messenger-supported wiring,
open wiring on insulators, or concealed knob-and-tube wiring,
conductors shall enter through insulating bushings or, in dry
locations, through flexible tubing extending from the last insulating
support to not less than 6 mm (1∕4 in.) inside the box and
beyond any cable clamps. Where nonmetallic-sheathed cable or
multiconductor Type UF cable is used, the sheath shall extend
not less than 6 mm (1∕4 in.) inside the box and beyond any
cable clamp. Except as provided in 300.15©, the wiring shall
be firmly secured to the box or conduit body. Where raceway
or cable is installed with metal boxes or conduit bodies, the
raceway or cable shall be secured to such boxes and conduit

Good point on the metal boxes but even under the 2017 NEC this wouldn’t apply to a NM connector in a panel as outlined in the OP.

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Why do you say that it wouldn’t apply? Is the panel not a metal box?

No, the panel enclosure is technically a cabinet and covered under a different code article, article 312. Boxes are under Article 314. An example of the metal box that Paul mentioned looks like this:

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Yup…it was to supplement your nonmetallic box statement.