Any reason not to use this cable for 4-wire humbuckers?

[rjb]

I just ran out of 4 core and chopped up a usb cable copper braided shield over a foil + separate earth wire + sd correct colours anyone know of any objections ?

I just did a bit of Googling USB cable specs, and found that the white and green are a twisted pair (meant for differential signal) and the red and black are designated +5V and Ground. I doubt it would make a noticeable difference, but because of the configuration, you will have different capacitance between the wire pairs.

Also, the spec says you're supposed to have copper braided shield over a foil, with drain wire - but some manufacturers don't follow the spec and make cheap cables with just a drain wire.