NYM is the german/austrian name for round Romex style cable, followed by number and size of conductors, e.g. NYM 3x1.5, the most commonly used cable type for any wiring, the number 3 means it's a blue conductor for neutral, black or brown for live and yellow/green for ground. Other common types are NYM 3x2.5 and NYM 5x2.5, NYM 4x1.5 is used for a 3way switch (common, 2 travelers and ground).
