We have some indoor transformers with exposed conductors (both primary and secondary). The arc flash ratings are "extreme danger" on the secondary side. Although I know there's no PPE available for "extreme danger" are there any arc flash barriers that would protect people at all?
As it is, no one can enter the room with these exposed conductors. Any suggestions? Thanks!

Other than a locked door with limited access to keys (Qualified personnel only) I can't see anything unless you care to add additional fencing/gate further limiting access, and appropriate signage. But then you do not state the voltage for the primary or secondary, so it's a crap shoot.

What working distance was used in the calculations? It is possible that a 'fence' could be installed to limit the approach to a distance that may lower the incident energy to a level for which PPE exists.

What other formula parameters were used to determine the incident energy? This sounds like the bus spacing may be like 'open-air', but any arc will definitely be occurring 'in a box'.