Mustang,
Again, there is nothing in Article 334 that requires this.
All the code says is that NM must be supported within 12" of every box (334.30), and within 8" of every single gang non metallic box. (314.17 (C) Exception)
In fact, if your loop is longer than 8" with single gang boxes, you have a violation of 314.17 (C) Exception.
Peter
