When the super cable goes vertical the texture stays horizontal. Would it be possible that the lines look the same as in horizontal placing, or is that intended? cable

This intended. This is how it looked in Minecraft 1.1 (this is a lot earlier then 1.7.10)

Yes this is a different texture pack but the cable is the same and a texture pack didn't have the control how the texture was rotated back then.
So this is how it was designed so this is how it is today xD

If you want to validate yourself, open a old minecraft instance with ic2 & rocket science installed and use the cable and see for yourself.

Edit:
A better image