310.15 B (3)

[mbrooke]

Does 310.15 B (3) apply to cable assemblies? I ask because it appears as though Table 310.15(B)(3)(a) applies only to conductors in the same raceway, not bundled MC, AC or Romex.

 

[Dennis Alwon]

Does 310.15 B (3) apply to cable assemblies? I ask because it appears as though Table 310.15(B)(3)(a) applies only to conductors in the same raceway, not bundled MC, AC or Romex.

Not sure what the issue is. It is pretty clear, IMO

(3) Adjustment Factors.
(a) More than Three Current-Carrying Conductors. Where the
number of current-carrying conductors in a raceway or cable
exceeds three, or where single conductors or multiconductor
cables are installed without maintaining spacing for a continuous
length longer than 600 mm (24 in.) and are not installed
in raceways, the allowable ampacity of each conductor shall be
reduced as shown in Table 310.15(B)(3)(a).

 

[infinity]

Yes it applies to cables. #12 AWG MC cable have their own 60% rule.

 

[mbrooke]

Not sure what the issue is. It is pretty clear, IMO

This fits the definition of a manufactured cable assembly, correct? I'm doubting myself today

 

[mbrooke]

Yes it applies to cables. #12 AWG MC cable have their own 60% rule.

Good point! But don't forget that all the conditions in (d) must be met.

 

[Carultch]

Not sure what the issue is. It is pretty clear, IMO

What is meant by "maintaining spacing"? Is there any measurable standard on what minimum spacing you are supposed to maintain?

 

[Dennis Alwon]

What is meant by "maintaining spacing"? Is there any measurable standard on what minimum spacing you are supposed to maintain?

AFAIK it can be a space....00000000001 inches? Who knows? They should say something like a half inch or so

 

[don_resqcapt19]

There were proposals to specify a specific distance, but they were rejected. However, it is my opinion if you do not take some step to actively maintain space, then spacing has not been maintained.