I am being challenged by our work group regarding working on a HV generator set (11kV) that is in close proximity to other operating generators at 11kV within a powerstation. From NFPA-70E Table 130.7(C)(15)(a) a generator would fall into the "other equipment" category and that the arc flash boundary is 40ft. Their concern is that they are within the arc flash boundary and doing any work (changing oil filters, adjusting the gas regulators or closing the circuit breaker from the local HMI panel) would require Cat4 PPE.
I have looked at several articles on Xchange and they all mention a risk assessment plus consider that the adjacent generators are operating under normal operating conditions. Taking this into account, there would be no need to wear Cat4 PPE while working next to operating generators.