Você não tem para fazer qualquer coisa para identificar os condutores. No entanto, você terá que se preocupar com o preenchimento da caixa, pois esses condutores terão que ser contados no cálculo de preenchimento.

National Electrical Code 2014

Chapter 3 Wiring Methods

Article 314 Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings, and Handhole Enclosures

314.16 Number of Conductors in Outlet, Device, and Junction Boxes, and Conduit Bodies.

(B) Box Fill Calculations.

(1) Conductor Fill. Each conductor that originates outside the box and terminates or is spliced within the box shall be counted once, and each conductor that passes through the box without splice or termination shall be counted once. Each loop or coil of unbroken conductor not less than twice the minimum length required for free conductors in 300.14 shall be counted twice. The conductor fill shall be calculated using Table 314.16(B). A conductor, no part of which leaves the box, shall not be counted.