Is cable support distance along the cable, or from the box?

[Johnny123]

334.30 says that NM cable has to be supported "within 300 mm (12 in) of every outlet box". But is that 12 in. along the cable, or 12 in. from the box? Is it acceptable to leave a bit of slack in the cable, so that along the cable it might be more like 18 in. even though the staple is within 12 in.?

 

[infinity]

Here's the section. Since it's about securing the cable the 12" dimension is for the length of cable permitted between the support and the box.

334.30 Securing and Supporting. Nonmetallic-sheathed
cable shall be supported and secured by staples, cable ties,
straps, hangers, or similar fittings designed and installed so
as not to damage the cable, at intervals not exceeding 1.4 m
(4 1 ? 2 ft) and within 300 mm (12 in.) of every outlet box,
junction box, cabinet, or fitting. Flat cables shall not be
stapled on edge.

 

[Johnny123]

Here's the section. Since it's about securing the cable the 12" dimension is for the length of cable permitted between the support and the box.

Is there a code section that specifies this, or is that simply the standard interpretation of the code?

 

[mwm1752]

Rob covered that pretty straight fowardNEC 2011 334.30 Securing and Supporting

at intervals not exceeding 1.4 m (41?2 ft) and within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting.

 

[qcroanoke]

"Flat cables shall not be stapled on edge"

I don't understand that part. What is the problem with it?

 

[infinity]

"Flat cables shall not be stapled on edge"

I don't understand that part. What is the problem with it?

Good question I would guess that someone thought that it would have a greater chance of being damaged. Also this was added in the 1993 NEC when cables were somewhat larger and stapling two on edge may have made the standard staples too short. I admit that all of this is conjecture. :roll:

 

[Johnny123]

Rob covered that pretty straight fowardNEC 2011 334.30 Securing and Supporting

at intervals not exceeding 1.4 m (41?2 ft) and within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting.

I guess my confusion comes in since some sections specifically mention that the measurement is along the cable. For example, the exception to 314.17(C), says:

...and where the cable is fastened within 200 mm (8 in.) of the box measured along the sheath...

 

[infinity]

I guess my confusion comes in since some sections specifically mention that the measurement is along the cable. For example, the exception to 314.17(C), says:

I can see the confusion but IMO that doesn't change the requirement of 334.30.

 

[mjf]

I rarely staple within 12" (along the sheathing) of the JB when installing "new construction" can fixtures.....The cable enters the JB from the top and loops (sweeps) to the nearest joist without putting what seems to be too much of a bend in the cable.

 

[fmtjfw]

intent to allow loops in some articles

intent to allow loops in some articles

551.47 Wiring Methods.
(J) Nonmetallic Box Without Cable Clamps. Nonmetallicsheathed
cables shall be secured and supported within
200 mm (8 in.) of a nonmetallic outlet box without cable
clamps. Where wiring devices with integral enclosures are
employed with a loop of extra cable to permit future replacement
of the device, the cable loop shall be considered
as an integral portion of the device.

552.48 Wiring Methods.
(I) Nonmetallic Box Without Cable Clamps.
Nonmetallic-sheathed cables shall be supported within
200 mm (8 in.) of a nonmetallic outlet box without cable
clamps.

Exception: Where wiring devices with integral enclosures
are employed with a loop of extra cable to permit future
replacement of the device, the cable loop shall be considered
as an integral portion of the device.

 

[mjf]

551.47 Wiring Methods.
(J) Nonmetallic Box Without Cable Clamps. Nonmetallicsheathed
cables shall be secured and supported within
200 mm (8 in.) of a nonmetallic outlet box without cable
clamps. Where wiring devices with integral enclosures are
employed with a loop of extra cable to permit future replacement
of the device, the cable loop shall be considered
as an integral portion of the device.

552.48 Wiring Methods.
(I) Nonmetallic Box Without Cable Clamps.
Nonmetallic-sheathed cables shall be supported within
200 mm (8 in.) of a nonmetallic outlet box without cable
clamps.

Exception: Where wiring devices with integral enclosures
are employed with a loop of extra cable to permit future
replacement of the device, the cable loop shall be considered
as an integral portion of the device.

That would probably apply to the "remodel" style, but not the "new construction" style.

If it's been more than 12" along the sheath of the cable, then I guess I'll just continue to be a code breaker!! I'm not going to mash the cable 90 degrees or try to put a staple within the luminaire bracket area.

Edit to add: I suppose I could use a cable-tie to the luminaire bracket to satisfy code (If I ever get called on it).