Changeover for backup generator

[JohnW2]

Interesting point, but then every portable appliance we use has a plugged earth connection - more so if we use extension leads.

True, but I would suggest that that is very different from having a plugged earth connection between the DNO (or local TT) earth and one's entire electrical installation.

As you go on to say, in common sense terms, the saving grace is that L, N and E are all plugged together - so that it would be impossible to be without an earth connection to one's installation without also being without L & N. I don't think it would be acceptable to have a situation in which it was possible to unplug the earth whilst L&N were still connected.

However, the regs seem to fail to correspond fully with that common sense, in that I think it's fairly clear that it would be non-compliant with regs to have a 3-pole switch (L, N & E) - even though, again, it would be impossible to disconnect E without also disconnecting L&N - so I'm really not sure what the regulatory situation is.

In a way, it's analogous to (say) a site cabin where there's a small CU inside for power and lights, and a blue inlet on the outside to plug the site supply into.

If the cabin has no other connection to earth (e.g. a local earth electrode), I would say that it's exactly analogous - but, again, I'm not sure what the regs have to say about that!

Kind Regards, John

 

[SimonH2]

However, the regs seem to fail to correspond fully with that common sense, in that I think it's fairly clear that it would be non-compliant with regs to have a 3-pole switch (L, N & E) - even though, again, it would be impossible to disconnect E without also disconnecting L&N - so I'm really not sure what the regulatory situation is.

That is a good point. I think that it perhaps shows (as if it needed demonstrating any more) that it's impossible to write sensible regs to cover every eventuality

 

[JohnW2]

That is a good point. I think that it perhaps shows (as if it needed demonstrating any more) that it's impossible to write sensible regs to cover every eventuality

Yes, I know from bitter experience that it's usually quite impossible to write rules, regulations, procedures, instructions or whatever that are totally exhaustive (i.e. covering every possible eventuality/scenario). However, it could be said to be "a bit rotten" when that lack of comprehensivity results in something being 'forbidden' that perhaps doesn't need to be (not that, in the context I mentioned, I can think of many sensible situations in which anyone would want to install a DP+E switch!).

Kind Regards, John

 

[EFLImpudence]

Comprehensivity ?

 

[JohnW2]

Comprehensivity ?

It was a choice between that and "comprehensiveness" - and I couldn't be bothered to look up which (if either!) was correct Do you know??

Kind Regards, John

 

[EFLImpudence]

Comprehensiveness.

Even Americans don't say comprehensivity.

 

[JohnW2]

Even Americans don't say comprehensivity.

Doesn't that mean that it must be correct?

Mind you, albeit not the world's most authoritative dictionary ....

Kind Regards, John

 

[Mat Burchett]

Hey all

Thanks for all the comments. Sorry for the late reply i checked to get notifications and didn't get one. i have just read everyone's comments.

My dads friend called me back after doing some research and the way i suggest is allowed. I did look at the 2 consumer way however the only 3 MCB i would take out would be shower, oven and shed, so as you can imagine all that work for 3 devices that wont be used is silly.

the only thing he did say which someone mentioned on here was earthing. he said we can tag on to the generator earth wire in to the armoured cable and at the house end come off the strands off the armored cable and connect to the house earthing.

The generator im looking at is a standby generator so it has the functions to allow waves and cope with computer equipment etc. all my servers are on a ups and surge plugs so that should eliminate most if not all the issues.

Thanks All.

 

[Mat Burchett]

I'm going to use

125 amp changeover switch 240V
10mm cable
5.2kw standby generator

 

[stillp]

The Concise Oxford has "comprehensiveness" but not "comprehensivity".

One thing that worries me about these generators for standby use is the source impedance, which might be sufficient to prevent ADS working correctly. Any thoughts on that?

 

[JohnW2]

One thing that worries me about these generators for standby use is the source impedance, which might be sufficient to prevent ADS working correctly. Any thoughts on that?

RCD(s) (if necessary).

Kind Regards, John

 

[stillp]

RCD(s) (if necessary).

What about overcurrent?

 

[JohnW2]

What about overcurrent?

You were talking about (and my reply related to) "ADS", and I don't think that is usually taken to relate to overcurrent (even though it does involve 'automatic disconnection'), does it? After all, it used to be called EEBADS, didn't it?

Kind Regards, John

 

[stillp]

Not in my machinery world!

 

[JohnW2]

Not in my machinery world!

Is that a reply to my first question or my second one?

Kind Regards, John