Floating or Bonded neutral

[Eliovi]

I just bought a Westinghouse generator (When 12000) and my neighbor is telling me no to use it until I know for sure if it is "Floating Neutral" or "Bonded Neutral" I don't really know what is he talking about. Why does it matter?

 

[Megawatt]

I just bought a Westinghouse generator (When 12000) and my neighbor is telling me no to use it until I know for sure if it is "Floating Neutral" or "Bonded Neutral" I don't really know what is he talking about. Why does it matter?

Most all generators have the neutral bonded to the frame. I have never seen a floating neutral in a generator. Use a multi meter to test your voltage and see what you get between the two phases and each phase to ground or neutral while it’s running.

 

[pc1966]

Here in the UK the "floating neutral" (also known as an IT supply from Isolé-Terre) is typically seen on small generators, up to a couple of kVA, as a cheaper means of protection compared to RCD (GFCI). The basic idea is if you get a single insulation fault then nobody gets a fatal shock.

However, that is only true if you have just a single load / simple distribution circuit. For anything larger that typically would feed a whole installation then the neutral point is connected to the earth (chassis, ground) making it a TN-S supply. You still need to reference the ground to the true Earth by means of some rod or similar, but once done it becomes similar to the utility supply and the usual disconnection by the RCD on any ground faults is pretty much OK.

The only places you see an IT supply used for large systems are places like hospital operating theatres, or ships, etc, where you really don't want a single fault to bring things down. But in these cases the regulations demand there is some form of insulation monitoring and that the system is under competent (in an electrical sense) supervision.