You do also need to be careful to check your local building codes. I was on a project several years ago where we were installing 277/480 wiring for warehouse lighting and power distribution, and were using BOY color coding. After about half the wiring for the lighting was completed, the local building inspector came out to sign off on another section of the project, and informed us that we were not supposed to be using orange for the middle phase. When we asked him why, he said that in their local building codes orange was only to be used for the high leg of 120/240 3phase wiring, and that the correct color for the middle phase was purple. He let us change the phase tape on all our big wires and phase tape the yellow wire already installed purple, but we had to complete the project with purple wire.
