Wind turbine generators can use voltages as high as 400/690 VAC to power yaw control, ventilation, and oil pump motors. Table 130.7(C)(150)(a) Arc Flash PPE Categories lists panel boards greater than 240 V up to 600V and 600 V class MCCs for arc flash PPE categories. From there it jumps to 1 kV and 2.3 kV categories. Would the PPE category for 690 V systems be the same as 600 V panel boards or MCCs? Has there been a change requested for the upcoming NFPA 70E to incorporate these higher voltages?
Am I looking at this wrong? I'd appreciate any guidance.
Stephen,
The short answer is that 690 volts does not meet the parameters stated in table 130.7(C)(15)(a) and cannot be used in the selection of PPE. The progression of PPE selection should follow along these lines;
(1) 130.5(A) An arc flash risk assessment shall be done to determine if an arc flash hazard exists, estimate the likelihood of an occurrence of injury, and determine if protective measures are needed, including PPE.
(2) If it is determined through the arc flash risk assessment that PPE is needed, the proper selection of PPE can come through either an incident energy analysis or the arc flash PPE category method...if the equipment falls within the parameters defined in the table.
I would have thought that with wind generation being a fairly recent technology that the associated electrical equipment involved would have already been evaluated for hazards and risk determination, and the equipment would be labeled in accordance to 130.5(H)
Blessings,