# What does NEC 2023 300.14 say about junctions with a dimension > 8"?

NEC 2023 300.14 states:

300.14 Length of Free Conductors at Outlets, Junctions, and Switch Points. At least 150 mm (6 in.) of free conductor, measured from the point in the box where it emerges from its raceway or cable sheath, shall be left at each outlet, junction, and switch point for splices or the connection of luminaires or devices. The 150 mm (6 in.) free conductor shall be permitted to be spliced or unspliced. Where the opening to an outlet, junction, or switch point is less than 200 mm (8 in.) in any dimension, each conductor shall be long enough to extend at least 75 mm (3 in.) outside the opening.

I do a fair bit of computer programming, and I'm reading this as a conditional missing an "else":

``````wireLength = 6" // measured from cable sheath/entrance to box
if (maxJunctionDimension < 8") {
wireLengthFromFront = 3"
} else {
wireLengthFromFront = ???"
}
``````

My best interpretation is "you don't need to worry about extending 3 inches outside the box if the box has a dimension > 8 inches" but I can't fathom why that would be the case.

Can anybody clarify what's going on here?

• What home improvement problem are you trying to solve?
– JACK
Commented Jun 15 at 1:48
• @JACK Ah, sorry. I'm doing some rough-in on my basement and I have a multi-gang switch that has a dimension > 8". I'm trying to figure out how much cable needs to be poking out of it. Commented Jun 15 at 2:49
• You're asking the wrong question. (Not really, just once you understand it a more intersting one is): Why wasn't the code written more simply as "at least 6 inches AND at least 3 inches past the front"? Period. Why the allowance for 6 inch wires in big boxes when, as noted in the answer, it's not practical? A six inch wire that can't reach 3 inches out would have to be in a box deeper than 3 inches, and then you would have to be splicing things with your hands deep inside it. What situations led to the inclusion of that allowance in NEC? Commented Jun 15 at 17:41
• minLen = (protrusion < 3 && max([frontEdges[]<8)) ? 6 : 9 - protrusion Commented Jun 15 at 17:57

Because you can put your hands into an 8" opening to work and make connections.

3" out of the box is so that you can make connections that will be stuffed back into small boxes you cannot reach into and make connections.

Mind you, an 8x8 or larger box other than a breaker panel is unusual in residential anyway.

Incorrect conditionals & variable in your pseudocode. Corrected below:

``````wireLength ≥ 6" // measured from cable sheath/entrance to box
if (minJunctionDimension < 8") {
wireLengthFromFront ≥ 3"
} else {
wireLengthFromFront ≥ 0"
}
``````

The language is quite specific that if the opening is less than 8" in any dimension you need (at least) 3" out the front, so a long gang box still needs 3" out the front. A box with a 7.95" x 24" opening would need 3" out the front. It does not say "if any dimension is greater than..."

A practical consideration rather than "code minimum" for a long gang box as you mention in comments is that apart from (at least) 6 inches and (at least) 3 inches out the front, you need enough wire length to make the required connections to devices, so if a wire is able to come out the front 3.5" and is 7" long but needs to go to the other end of the box to hit the switch or receptacle it connects to, then...it needs to be longer. If it's more than 11.99" you'll need to count it as two wires for box fill. However, you can pigtail for free, box-fill-count-wise; and the code minimum makes sure you can, in fact, make a pigtail connection.

• Thank you for clarifying my reading of that section of code; for some reason I was interpreting it as "any dimension > inches" which was not correct. Your explanation clears everything up - thank you! Commented Jun 15 at 17:23
• In a breaker panel any 6 inch wire will reach 3 inches out. I can't think of a situation that would benefit from the rule's relaxed grey zone of a 6 inch wire that can't reach outside a large-fronted box. Unless the box is so big you can step into it. But then, I'm pretty sure NEC would not be the governing regs. Commented Jun 15 at 17:45
• @jay613 NEC covers far more than houses, and large boxes that are more than 6" deep exist. Commented Jun 15 at 20:13