The way that I understand it is that there are two different scenarios, which are a floating neutral and and open neutral.
With a floating neutral all loads have a neutral wire connecting the load back to the neutral point of the transformer secondary, however the netural point is not bonded to ground. In this case, depending on the load balance, the neutral voltage with reference to ground is free to float to any voltage determinded by the current impbalance. (Ia + Ib + Ic = In). It is possible in this case to then have a neutral reference with 100V like someone had mentioned, and therefore have an higher than rated voltage across L-N loads. Bonding this neutral point to ground ensures that the neutral point has a 0V reference and all L-N loads are correct voltge.