All of this is covered in BS 7430, quite adequately. Other guidance also covers it.

sparkiemike said:

1. I can't see what function any earthing would provide as the N and E are not connected, if they were connected it would result in catastrophic failure of the machine. Is this correct?

If N and E are connected, then imagine an accident in which the line conductor is accidentally "spiked" to the ground. What happens then, is "exposed-conductive-parts" are immediately at full line voltage, which is obviously very dangerous. It's imperative if you intend to operate this as a floating system, for the generator to have an RCD immediately at its output terminals, just in case this happens - at least the poor person touching the "exposed-conductive-parts" stands a chance. This is illustrated in A722 of BS 7671.

sparkiemike said:

2. Secondly I am correct in thinking that this generator is not suitable for connecting to a house, and he would be better off getting a new machine with correct type earthing arrangement, or are there alternative ways of connecting this generator safely?

This kind of generator is definitely suitable for connecting to a house, either stand-alone, or as a switched-alternative of supply.

BUT

(a) If stand-alone (no grid supply), a consumer's earth electrode is required to make it a proper TN-S system - either connected to MET, or directly to the generator frame and neutral; or

(b) If a switched-alternative to the grid supply, the installation must comply with Regulation 21 of ESQCR. All live conductors must be disconnected from the Grid when the generator is in operation, and in accordance with Regulation 551.4.3.2.1, a consumer's earth electrode is required. The switching arrangement should also consider that both BS 7671 and ESQCR prohibit two N-E connections at the same time, so this generator must only be connected by a change-over switch.

gkenyon said:

All of this is covered in BS 7430, quite adequately. Other guidance also covers it.

Unfortunately I don't have access to a copy and at £289 don't think I will be buying one any time soon.

sparkiemike said:

1. I can't see what function any earthing would provide as the N and E are not connected, if they were connected it would result in catastrophic failure of the machine. Is this correct?

If N and E are connected, ...

N and E are not connected on this genset. My preference would be to have a NE link and install an earth electrode making it a TNS system. Then connect the generator by CEE plug and socket with change-over switch.

... then imagine an accident in which the line conductor is accidentally "spiked" to the ground. What happens then, is "exposed-conductive-parts" are immediately at full line voltage, which is obviously very dangerous. It's imperative if you intend to operate this as a floating system, for the generator to have an RCD immediately at its output terminals, just in case this happens - at least the poor person touching the "exposed-conductive-parts" stands a chance. This is illustrated in A722 of BS 7671.

sparkiemike said:

2. Secondly I am correct in thinking that this generator is not suitable for connecting to a house, and he would be better off getting a new machine with correct type earthing arrangement, or are there alternative ways of connecting this generator safely?

This kind of generator is definitely suitable for connecting to a house, either stand-alone, or as a switched-alternative of supply.

BUT

(a) If stand-alone (no grid supply), a consumer's earth electrode is required to make it a proper TN-S system - either connected to MET, or directly to the generator frame and neutral; or

(b) If a switched-alternative to the grid supply, the installation must comply with Regulation 21 of ESQCR. All live conductors must be disconnected from the Grid when the generator is in operation, and in accordance with Regulation 551.4.3.2.1, a consumer's earth electrode is required. The switching arrangement should also consider that both BS 7671 and ESQCR prohibit two N-E connections at the same time, so this generator must only be connected by a change-over switch.

But you would still need a NE link on the generator for option (b)?

But you would still need a NE link on the generator for option (b)?

Yes !! ( If not how do your RCDs ADS etc work without a sense of neutral being near ground and live not being. ? )
and some sort of RCD at the genset after the NE split please, perhaps a 100mA delay type if you do not want one-out all-out tripping. When I have done this in the field I have used a clear bodied plug into the genset with the NE link and a label visible inside

 the plug. (this example is a WALTHER-210306CL other makes exist.)

The very next thing after the plug is an RCD.

Mike

But you would still need a NE link on the generator for option (b)?

Yes !! ( If not how do your RCDs ADS etc work without a sense of neutral being near ground and live not being. ? )
and some sort of RCD at the genset after the NE split please, perhaps a 100mA delay type if you do not want one-out all-out tripping. When I have done this in the field I have used a clear bodied plug into the genset with the NE link and a label visible inside

 the plug. (this example is a WALTHER-210306CL other makes exist.)

The very next thing after the plug is an RCD.

Mike