Generator advice

[Spark123]

Instead of one big c/o switch, how about feeding the ccts. you want backed up with spurs, and using a panel of small c/o switches, after the CU?
You would need to switch both live & neutral, and could feed the Genny in via it's own small CU with RCCD & MCB's. Genny frame "earth" would = existing supply earth?
My Genny is "floating neutral", and IMHO, thats what you want.
I've bonded "neutral" to earth at the supply side of the RCCD; house is TT.
I'me not sure if FN is normal for portables sold here, or whether non FN's are allowed under CE regs?

Afaik floating generator neutral can be classed as protection by electrical separation subject to the conditions laid down in the IEE regs.

You have bonded Neutral and Earth together before RCD, please can you explain?

 

[Chris.J]

Well, although leaving the Genny o/p "floating" would be safe, I prefer the neutral to be at earth potential "where you expect it to be", so I have made this link pre RCCB. It also means that the Genny mimics the local sub station, and the RCCD provides protection in the usual way.

 

[Spark123]

Your house is TT and you have made a TN-S connection though?
Does this connect to the normal supply when the generator is not in use?

 

[Chris.J]

Your house is TT and you have made a TN-S connection though?

Does this connect to the normal supply when the generator is not in use?

When I remarked in my first post "Genny frame "earth" would = existing supply earth?", I suppose it would have been better to use " house system" rather than "supply".
I was posing the general question "should Genny frame be connected to system earth, whatever type that is"?, and suggesting that BAS should consider it.
What do you think?
In my case, I have no earth from the DNO, house system earth goes to a rod, and Genny frame is connected to it.

 

[Spark123]

We are not allowed to rely on the DNO supply earth for a generator running in parallel with a TN system, an earth electrode should be installed.
As you are on a TT supply it should be OK to use your earth for your generator, remembering when the generator is running the supply will be TN and hence the installation also needs to comply with TN regs.
Does the supply which can be plugged into the generator when needed also plug into the house TT supply when the generator is not required? I ask as you say you have shorted N-E pre RCCB which if connected to a TT supply may short your earth electrode and the DNO neutral.

 

[Chris.J]

We are not allowed to rely on the DNO supply earth for a generator running in parallel with a TN system, an earth electrode should be installed.
That seems to answer the question I posed.
As you are on a TT supply it should be OK to use your earth for your generator, remembering when the generator is running the supply will be TN and hence the installation also needs to comply with TN regs.
Does the supply which can be plugged into the generator when needed also plug into the house TT supply when the generator is not required? I ask as you say you have shorted N-E pre RCCB which if connected to a TT supply may short your earth electrode and the DNO neutral.

Regret don't quite follow?
The spurs that feed loads (Boiler, Fridge etc), are the same for both power sources, they are individually switched on DP switches between the supplies, on the load side of the CU's.
The earths are unswitched, and all go to the rod.
There is no connection between DNO neutral and the system earth, for either supply.
Does that explain it better?
Regards, Chris.

 

[Spark123]

Yup, I got myself muddled up when you wrote:

You would need to switch both live & neutral, and could feed the Genny in via it's own small CU with RCCD & MCB's. Genny frame "earth" would = existing supply earth?

as opposed to "this is what I have".

I've bonded "neutral" to earth at the supply side of the RCCD; house is TT.

I took this as written, as opposed to in the context of above, I take it you mean the link is on the generator CU only.

 

[Chris.J]

I've bonded "neutral" to earth at the supply side of the RCCD; house is TT.

I took this as written, as opposed to in the context of above, I take it you mean the link is on the generator CU only.

Yes, that's what I've done.

Appreciate your comments, Chris.