There are tables available to use if your facility meets certain requirements. In order to determine if you meet those requirements, you will need information from the utility and information about your distribution system to do a basic calculation. If you fall into the requirements, you can use the tables found in 70E and label your equipment accordingly. If not, you will need to do a full arc flash study and then apply labels based on that. In either case, you will probably need to employ an outiside engineer to do the basic calculation. Just make sure you understand that an option is available if you fit, and the high cost of an arc flash study may not be necessary.
TxEngr