What about the earthing of generators ?

[VicS]

There has been a thread running about earthing of inverters and the use of RCDs with them

http://www.ybw.com/forums/showthread.php?500331-quot-Occasional-quot-240v

Presumably a similar situation exits regarding the use of generators, portable or installed.

If you want the protection an RCD gives, be that a plug in one used with a potable generator, the shorepower RCD if you connect the generator via the shorepower inlet or a dedicated RCD if the generator is a fixed installation it is obvious that the generator output must be "neutral earth bonded" Are they ? Do the instruction manuals touch on this subject?

 

[rogerthebodger]

There has been a thread running about earthing of inverters and the use of RCDs with them

http://www.ybw.com/forums/showthread.php?500331-quot-Occasional-quot-240v

Presumably a similar situation exits regarding the use of generators, portable or installed.

If you want the protection an RCD gives, be that a plug in one used with a potable generator, the shorepower RCD if you connect the generator via the shorepower inlet or a dedicated RCD if the generator is a fixed installation it is obvious that the generator output must be "neutral earth bonded" Are they ? Do the instruction manuals touch on this subject?

You are correct Vic the problem is that most people consider a generator like a appliance and connect the frame to an earth spike only but its the earth wire and frame that must also be connected to the neutral or what becomes the neutral once the connection is made.

I know this has been discussed before in the dim and distant past on this forum.

 

[matthewriches]

The first thing to think about is that generators are not a "clean source" of power. They need a lot of smoothing to be "nice".

The majority of the small nasty noisy hairdryer things are centre tapped earth. Some of the super duper Chinese million watt specials are an accident waiting to happen in that every model seems to be different, some centre tapped, some ropey 3 phase with star, some floating.

The more quality stuff, a good amount of Northan Lights, Fischer Panda, etc types are centre tapped earth as are the majority of Stephill generators.

The large boats I work on tend to have prime generators >6000v with local step down transformers (this cleans the power up) and local area backup generators standard 3 phase. Again almost all centre tapped. All electric motors onboard are generally without a neutral.

I've not explored inverter generators in great detail as my customers don't use them but the few I have seen have been of a floating variety which brings us back to our 2 faults to trip an RCD conflab, to neutralise or not to neutralise debate.

I haven't got to start proving generators now, have I? If in doubt, contact a suitably qualified electrician.