Refresh my memory: # of NM conductors per staple

[Chuck Evans]

I seem to recall thet there is a limit to the number of NM conductors that can be secured under a single staple, but I can't find it.

Can anyone confirm if there is a specific limit? What it is? and an NEC reference if you know it.

This new construction installation has 5 conductors under one staple in an attic.

[Jeffrey R. Pope]

I don't know of any restriction to the number of cables.

334.30 Securing and Supporting.

Nonmetallic-sheathed cable shall be 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 (41⁄2 ft) and within 300 mm (12 in.) of every cabinet, box, or fitting. Flat cables shall not be stapled on edge.

[Chuck Evans]

Thanks Jeff.

That's the same article I found that when I was looking. Since I couldn't find a reference, I left it out of the report. I swear I remember being told something about it at some point, but it may be a figment of my imagination.

[Jim Port]

The limit would be found on the package for the staples. The only NEC that would apply would be 110.3, listing and labeling usage. If the staple was only listed for say two cables it would be an issue. However, that staple is for a larger feeder cable so you probably would not find a size combination for use with smaller cables.

IMO not a big deal.

[Larry D. Kage]

Originally Posted by Jim Port

IMO not a big deal.

I see it the same...

[Paul W. Abernathy]

When it becomes a "big deal" is when they are installed improperly. indeed, you have to turn to the manufacturer for the limitations of their product ( NEC 110.3(B)). I as an inspector do have a problem with it when I know the length of the staple in use and the number of cables under it but again you need to know the manufacturers information. You will notice that the manufactures that allow more than (2) laying FLAT under a staple will have longer staples.

However, as a HI be careful of calling something like this out because chances are 100% you dont have that information and if the staple is holding, no obvious damage to the cable jacket or crushing of the jacket which could affect the conductors within...I would assume it is compliant and move on.

[Rick Marton]

Paul, Back in the late 90's I roughed in a new home and put two wires under a staple throughout the house and the electrical inspector told us either to seperate or derate the wire. It's only one inspectors interpretation, but ever since then I keep them all seperate. Nowadys the amp ratings of the wires have increase so it would not matter if it was derated. Rick

[Rick Marton]

Originally Posted by rmarton

Paul, Back in the late 80's I roughed in a new home and put two wires under a staple throughout the house and the electrical inspector told us either to seperate or derate the wire. It's only one inspectors interpretation, but ever since then I keep them all seperate. Nowadys the amp ratings of the wires have increase so it would not matter if it was derated. Rick

Actually it was the late 80's

[Paul W. Abernathy]

lol......derating (2) NM Cables in the 80's...lol......now that funny.