You need a system study to determine the energy at a certain point in your electrical network. So you need to know some details of the protections upstream and internally within your equioment to give an idea of the arc flash energy / duration that then deterimes the calorific value of the PPE required.  Likely all your installations might be similar so you could run a series of small studies using ETAP arc flash module to determine a range of potential arc flash values.  I work in commissioning and things like phase rotation checks nearly always involve live work, but consider if you can use a phase roation meter with crocodile clip probes, connected onto the test locations while the bars are dead, then energised with all personel well out of the way of the probes / meters; that is far safer than (2 people?) leaning into a live panel with point probles, the arc flash risk of live work still exists but the safety barrier is your procedures not the arc rated PPE. Lert  us know how you get on.

Worth noting that you can reduce the arc flash potential by temporarily droppping the upsteam / incoming fuse or MCB rating, as doubtful lot of fault finding will involve running the machine at full load. Once you are happy the kir is running ok, the last job is to put back in the larger fuse. 

You need a system study to determine the energy at a certain point in your electrical network. So you need to know some details of the protections upstream and internally within your equioment to give an idea of the arc flash energy / duration that then deterimes the calorific value of the PPE required.  Likely all your installations might be similar so you could run a series of small studies using ETAP arc flash module to determine a range of potential arc flash values.  I work in commissioning and things like phase rotation checks nearly always involve live work, but consider if you can use a phase roation meter with crocodile clip probes, connected onto the test locations while the bars are dead, then energised with all personel well out of the way of the probes / meters; that is far safer than (2 people?) leaning into a live panel with point probles, the arc flash risk of live work still exists but the safety barrier is your procedures not the arc rated PPE. Lert  us know how you get on.

Worth noting that you can reduce the arc flash potential by temporarily droppping the upsteam / incoming fuse or MCB rating, as doubtful lot of fault finding will involve running the machine at full load. Once you are happy the kir is running ok, the last job is to put back in the larger fuse.