What if line and neutral wires are interchanged in three phase supply?

During an installation of Autoclave our technician wrongly connected the three phase wires( he connected the line wire to neutral wire and neutral wire to line) consequently when the machine was turned ON the fuse was blown with a smell that something was burning. Now my question is, (1) what happens when the line and neutral wires interchanged? 
(2) Does it damage the instrument if the two lines are interchanged?

Whenever we turns the machine ON it blows the fuse right after turning it ON.

If the autoclave is a single phase connection, then reversing the neutral and phase should not worry much - it will be the same voltage.However if you connect a single phase load across 2 phases, you will get the phase-neutral voltage multiplied by the square root of 3 (1.732) so for 240V that would be 415V.  That would blow almost anything you connected to it.If the autoclave was a 3 phase connection it would probably have had 3 elements each connected phase-neutral.  If you interchanged neutral with one phase, 2 elements would have 415V across them and the other one would have normal voltage.  The easiest way to explain this is with a phase diagram (below).If the fuses are still blowing with corrected connection it is likely that in blowing an element has shorted to earth and thus drawing excessive current.  Alternatively if there are control electronics involved, they would probably have blown as well with nearly double the rated voltage across them.Where I am (Australia) we use 240V mains - if you use 110 or 120V mains your phase-phase voltage would be 190 or 208V, but the theory is the same.

Dear David, Thanks  for your reply. Autoclave is three phase, having five wires. L1, L2, L3, Neutral and Ground. Unfortunately, our technician, instead of L3 connected neutral wire to it. So when we turn the machine ON firstly it turned ON and then in the next movement the fuse was blown.
As Autoclave is three phase so if I'm not wrong due to high voltage, any component in the machine is burn or damaged? We had emailed to the Autoclave manufacturer they are saying that it could be that motor or relay is damaged, but I could not understand if the motor is damaged then why the fuse is being blown every time??

OK, my diagram showed L1 and Neutral swapped, but the same conditions apply.As I know nothing about what is in your autoclave I can't really comment further.  If you connected a motor with a phase and neutral reversed your phasing would be all wrong and the motor might well burn out. Any other components would have probably got 415 V instead of 220V and would probably also have burned out as well.You really need to get a qualified electrician to come and check it out. (and you should have got one to come and connect it as well!)  The manufacturer may give you an idea as to which parts would be burned but it sounds like you will have a hefty repair bill I'm afraid....