Standards:
ÖVE / ÖNORM E 8242
DIN EN 60228 Cl.1(RE) and cl.2(RM) (construction)
J: One core green/yellow, other cores are colored
One core green/yellow, other cores are colored
JZ: One core green/yellow, other cores are black with figures
OZ: every core is black with figures
Colored cores for 7 cores : core colours: green/yellow, violet, pink, orange, brown, black, blue