I have two electric panels 3000 and 4000 amps. What would be the proper Arch Flash Labeling on these panels? This is a high rise commercial building and maintenance staff does not have the authority to open these panels. Thanks.
You need an arc flash study done for it, which also requires a short circuit and coordination study. Hire an engineer who has done this before. When you are at it, it may be not cost you much more to get rest of the system.
I'm just seconding Rafiq's answer. You need an engineer to do the work first (arc flash hazard analysis), and he or she will advise the required labeling.