What spacing must be maintained when working with nonmetallic sheathed cable?

[Tester101]

[B]334.80 Ampacity[/B] ... Where more than two NM cables containing two or more current-carrying conductors are installed, without [I][B]maintaining spacing[/B][/I] between the cables, through the same opening in wood framing that is to be fire- or draft-stopped using thermal insulation, caulk, or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a) and the provisions of 310.15(A)(2), Exception, shall not apply. 
Where more than two NM cables containing two or more current-carrying conductors are installed in contact with thermal insulation without [I][B]maintaining spacing[/B][/I] between cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).

Where is the spacing between cables that must be maintained defined?

 

[Dennis Alwon]

That is a question that has no answer. The code says to maintain spacing without a clue to distance. IMO that means as long as the cables don't touch then the spacing requirement is satisfied

 

[suemarkp]

In the same place that defines what is subject to physical damage.

Its in the inspectors head. Hopefully your local inspection department has some guidelines so all inspectors in a locality use the same judgement criteria. I hate it when inspectors A says to do this and then inspector B says that's not good enough.

 

[Gregg Harris]

[B]334.80 Ampacity[/B] ... Where more than two NM cables containing two or more current-carrying conductors are installed, without [I][B]maintaining spacing[/B][/I] between the cables, through the same opening in wood framing that is to be fire- or draft-stopped using thermal insulation, caulk, or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a) and the provisions of 310.15(A)(2), Exception, shall not apply. 
Where more than two NM cables containing two or more current-carrying conductors are installed in contact with thermal insulation without [I][B]maintaining spacing[/B][/I] between cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).

Where is the spacing between cables that must be maintained defined?

Do you have a specific situation you are asking about? You are in the right section.

 

[don_resqcapt19]

Do you have a specific situation you are asking about? You are in the right section.

As far as I know, there is nothing in the NEC that defines "spacing". There are rules that require you to have spacing, but no direction as to how big of a gap equals spacing.

 

[George Stolz]

One can make assumptions based on the allowances for MC and AC cable in 310.15(B), but as stated above there are no specifics given.

 

[Gregg Harris]

As far as I know, there is nothing in the NEC that defines "spacing". There are rules that require you to have spacing, but no direction as to how big of a gap equals spacing.

True nothing specific on the spacing. But the calculation for bundling may apply for the OP.
there may be a 2 inch hole with 15 home runs feeding to the panel.

 

[don_resqcapt19]

True nothing specific on the spacing. But the calculation for bundling may apply for the OP.
there may be a 2 inch hole with 15 home runs feeding to the panel.

Yes it might apply, but since we don't know what spacing is required we don't know if that rule applies.