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Tuesday, May 3, 2016
Question:
How many m.c. cables can I use tie straps under without bundling?
Thomas Sievert
A
Answer:
Hey Thomas thanks for your question. I'm guessing you are referring to the rule about ampacity adjustment in 310.15(B)(3)(a). Two 2-wire cables that were installed without maintaining a space (bundled) would be 4 current carrying conductors and the adjustment factors from Table TABLE 310.15(B)(3)(a) unless you can apply one of the provisions such as that in 310.15(B)(3)(a)(4). You will get to use the 90 degree column in Table 310.15(B)(16) to apply the adjustment factor to, even if you don't meet the other provision, so it isn't that bad until you get quite a few cables. It can also vary depending on how many current carrying conductors are in each cable.