At our plant we service our large draw out breakers every 3 years on a rotation. They are inspected, tested, lubricated, cleaned and or replaced. Sometimes taken completely apart, re-zinced parts and re-tinned terminals. The same is done for the relay and trip units.
For the modeling of your arc flash, there is a selection in your arc flash tab. You can select "include main breaker" or "exclude main breaker". This significantly changes your calories on the secondary of a transformer switchgear.
In typical pullout switchgear, the main breaker is in a different compartment from the rest of the breakers. For the main breaker compartment, you want to "exclude the main breaker" because the line side of the breaker will cause the most arc flash. This will have a large arc flash rating, put the big sticker on that compartment.
For all the downstream breaker compartments that are separate, you want to select "include main breaker" for all these compartments because the line side of the main breaker is no longer in play. This will significantly reduce your arc flash calories in these downstream compartments because that main breaker will significantly reduce arc flash. Use the smaller calorie stickers for these feeder breakers in this case.
For example, on a 2300 KVA transformer with a main breaker and a fuse before the primary of transformer, 4160V to 480V, 3200 Amp breaker, if I EXCLUDE the main breaker, the calories are 73 per cm squared on the line side of that breaker, which is correct for main breaker compartment. If I click the INCLUDE main breaker for all the feeder breakers in different cabinets, the bus now drops to 18 calories per cm squared, big difference!!!
In a typical I line panel, the main breaker is wide open to the rest of the panel with the cover removed. The line side of the breaker is exposed, therefore, you must use the worst case for the whole panel, "EXCLUDE" main breaker.
In your case, you have molded case breakers and switches. Is the main breaker in a separate compartment from the rest of the breakers? Either way, exclude main breaker calculation for that main breaker compartment. Is the main breaker open to the rest of the feeder breakers? If so, exclude main breaker calculation for all the feeder breakers as well. If main breaker is in its own compartment, include the main breaker calculation for all downstream breakers and their arc flash stickers which will be much less calories.
173 calories per cm squared sounds real high. Something likely not quite right. My 2300 KVA example above I bet is pretty close to your bigger 4000 amp breaker situation. However, if there is no fuse before the primary of the transformer, perhaps 173 calories is correct.
When your compartments are closed tightly as in your case, arc flash is theoretically not suppose to be able to jump out and get you. "Theoretically".
That being said, I would personally still wear a 40 calorie full suit when switching any of these breakers or switches in your case with the compartments COMPLETELY closed.
Also, look into getting your gear cleaned, serviced, etc. Dust is a big player in arc flash accidents. Faulty breakers are also a big player in arc flash accidents. Although you can't service or replace molded case breakers, you can certainly test them and replace bad ones. Get the primary of the transformer completely turned off before attempting to service the internals of this electrical gear!