Backup generator for domestic property

[radosparks]

With the weather and power outages recently, I have a customer who has bought a 6kw generator he wanted to 'plug' into his consumer unit so when the power goes off he can use the backup. He wants me to fit.

I want to check I have covered everything before I start. There are a few points I have read which I don't fully see the need for if anyone can clarify.

- Generator on 6mm flex / swa feeding gen side of changeover switch L - N via rcd and 32a MCB (as well as gen overload).
- Suppliers feed rerouted to changeover switch L - N.
- Out L - N of changeover switch to consumer unit main switch.
- N-E connection present at generator to give reference for RCD in generator mode.
- Off position, both supplies cannot be connected together.

Earth;

- Connect earth from generator to MET of installation. The generator earth will now be at same level as the rest of the installation.

Now I've read some posts requiring an earth rod at under 20ohms (this I have also seen as 200ohms as its a reference) connected to the MET (and can't be tested with a loop tester). Others the rod connected to the generator. Others not at all. Any thoughts?

Cheers.

 

[jackhammerJIM]

have a look in GN3 it shows a diagram and explains how to take RA on a generator setup .

 

[PEG]

You need to fully separate the generator from the DNO supply including earth arrangements,you will probably need a larger output,and do NOT believe the customers "sensible use" promise,he,she,them and the visitors will turn everything on. I too have seen the legendary double ended plug top lead and the post-it note-on-the-cu method...i have also seen a lot of melted genys...happy trails

 

[Engineer54]

I guess it depends on how technically aware they are. Not all householders are idiots.

Don't you believe any of it, when it comes to saving money, commonsense seems to disappear from the equation!!

 

[Engineer54]

I'm having problems with that changeover switch wiring layout, i'll get back to it later on. From what i'm seeing (after admittedly a very short look see) the generator is providing the sole earth to the CU!! Just wondering how the DNO earth get's connected to the CU, when the C/O switch is in the prime supply (DNO) position?? ...lol!!