Found some work

[CIECO]

800 Amp 480 volt top feed burned up for no apparent reason

 

[chris kennedy]

What make/model panel is that?

 

[cowboyjwc]

Wow. Panel went boom!

 

[dejeud]

800 Amp 480 volt top feed burned up for no apparent reason

Looks like FPE breakers, and I assume the bottom part is where the ungrounded conductors used to come in.

So my answer is, either:

1: Someone stuck a crowbar between the phases.
or
2: If that's an FPE panel, it's safe to assume that the breaker ahead is an FP as well, which, we all know they never trip.

 

[CIECO]

GE spectra series with TEY circuit breakers and it did not look to old. Cover was still in tact. In a room with the MDP

 

[e57]

I usually call this type of thing a Salvador Dali.

 

[e57]

Looks like FPE breakers, and I assume the bottom part is where the ungrounded conductors used to come in.

Yeah - where are they?

 

[wireguru]

GE spectra series with TEY circuit breakers and it did not look to old. Cover was still in tact. In a room with the MDP

take a look at this http://www.hss.energy.gov/csa/csp/aip/accidents/typea/Type_A_Electrical_Arc_SLAC_20041011.pdf what looks like the same type of panel exploded from damaged insulator where busses pass over eachother behind the breakers

 

[CIECO]

I believe that there was a Insulator supporting the bottom of the buss but I don't know how you get a phase to phase fault unless the neutral to phase fault started it. the panal board is not of the same design as the link, but it's a GE.