Generator change over switch

Marine Inverters switch the PE as standard in thru-put.

2011

Reisers wrote: »

Obvious to an electrician

Nope, I am an electrician

As I am sure you know there can be valid reasons for switching earths in some scenarios.

Tuco88

If the premises had a TN-S system. I would imagine not switching the DSO Neutral would be problematic if a fault occurred on the generator side like a broken neutral?

2011

Tuco88 wrote: »

If the premises had a TN-S system. I would imagine not switching the DSO Neutral would be problematic if a fault occurred on the generator side like a broken neutral?

I have never seen TN-S used by ESBN, in fact I would be surprised if they use it at all.

Do you mean that because TN-S is neutralized at the local transformer a broken neutral on the utility side would mean it would not be neutralized anywhere? I suppose that when there is a power outage it is possible that as part of the repairs the star point of the local transformer may no longer be grounded.

I'm not sure but perhaps in this more unusual example it may make sense to break the neutral so that a generator specific neutraliziation point could be switched into circuit when the generator is in use. To me it would seem risky to have the only neutralization point external to the installation. I am open to correction on this, but that is my opinion.

As you know most installations in Ireland are TN-C-S, so normally this concern would not apply.

2011

2011 wrote: »

As I am sure you know there can be valid reasons for switching earths in some scenarios.

...couldn't afford a transformer?

Bruthal

Tuco88 wrote: »

If the premises had a TN-S system. I would imagine not switching the DSO Neutral would be problematic if a fault occurred on the generator side like a broken neutral?

A 3 phase generator, as with any 3 phase supply, would be problematic with open neutral on any earthing system.

Bruthal

Bruthal wrote: »

A 3 phase generator, as with any 3 phase supply, would be problematic with open neutral on any earthing system.

I've seen that cost clients 10s of thousands of Eurobucks. Bad distro. Technician plugged in without metering. Blew the PSUs outtov one third of a festival stage video wall

Bruthal

Sir Liamalot wrote: »

I've seen that cost clients 10s of thousands of Eurobucks. Bad distro. Technician plugged in without metering. Blew the PSUs outtov one third of a festival stage video wall

Yea I seen it myself in a neighbours house a few years ago. Lot if ruined items.

Reisers

Bruthal wrote: »

Yea I seen it myself in a neighbours house a few years ago. Lot if ruined items.

I've done it and seen it happen

Reisers

Its probably the reason I only buy electrical equipment with external power supplies where possible and separates- none of this combi stuff

I'd advise metering the supply over installing remote detonation devices.

Reisers

Sir Liamalot wrote: »

Marine Inverters switch the PE as standard in thru-put.

maybe standard in the sailing or boating forum but has no relevance here

"switching devices shall not be installed in a protective conductor"

Rules 543.3.3

Reisers

2011 wrote: »

I am not trying to be smart but it is not obvious.

I'd say it's fairly obvious to any electrician

The PE isn't normally referred to as a pole or a supply pole for switching purposes


Poles refer to live conductors

2011

Reisers wrote: »

I'd say it's fairly obvious to any electrician

As I am an electrician I can comment with some authority on what I feel is or is not obvious to an electrician

Anyway you have clarified your position and we all agree on this point so let’s move on rather than argue about it.

How about answering the questions put to you here?

https://www.boards.ie/vbulletin/showpost.php?p=110941597&postcount=27

Reisers

2011 wrote: »

As I am an electrician I can comment with some authority on what I feel is or is not obvious to an electrician

Anyway you have clarified your position and we all agree on this point so let’s move on rather than argue about it.

How about answering the questions put to you here?

https://www.boards.ie/vbulletin/showpost.php?p=110941597&postcount=27

I don't fit domestic changeover switches as generators connected are not typically fit for the purpose


If i had to fit a changeover switch and a plug for a domestic generator to be connected later- i would be switching all live poles .

2011

Reisers wrote: »

I don't fit domestic changeover switches as generators connected are not typically fit for the purpose

Why are the generators that are typically fitted not fit for purpose?

If i had to fit a changeover switch and a plug for a domestic generator to be connected later- i would be switching all live poles .

Yeah I see that.

Reisers wrote: »

I already said in my post the neutral doesn't have to be switched according to rules, I don't know why you're asking the question.

I'm asking because you also say that ESBN "won't pass it without neutral switched" in the very next post.
This seems suggest that ESBN won't permit something that is complaint with the rules. Can you explain?

Reisers wrote: »

Most of these domestic installs the spark is leaving a 63A plug for a Genny

Read the previous post by Steve and you will see that you are making a stronger argument for not switching the neutral.

Someone will come along after and connect a 110-0-110 genny and short it

And what would the consequence of that be? Would anyone be at risk and how?

Are you aruging this a valid reason for running the risk that the genny would not be neutralized at any point?

Steve

Reisers wrote: »

Someone will come along after and connect a 110-0-110 genny and short it

2011 wrote: »

And what would the consequence of that be? Would anyone be at risk and how?

This is perplexing me. do 110-0-110 generators even exist? If so, why?
110VAC is considered lethal which is why 55-0-55 is used on sites via a CTE traffo.

I don't see a reason for 110-0-110 to exist, but I'm open to correction.

Yes, I've googled them, no results.

Theory aside, in real life, this would just stall the generator and stop it instantly as it wouldn't handle the short circuit current. I've seen 1200A FGW sets lock up instantly - installed as max demand changeover in shopping centres - because of no load shedding before the ACB's switched.

Reisers

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=24199

I was called out to a changeover switch

There was N-E faults on the lighting circuits draining the generator with nothing switched on.

2011

Reisers wrote: »

I was called out to a changeover switch

There was N-E faults on the lighting circuits draining the generator with nothing switched on.

That doesn’t even make sense.

gctest50

Reisers wrote: »

I don't fit domestic changeover switches as generators connected are not typically fit for the purpose


If i had to fit a changeover switch and a plug for a domestic generator to be connected later- i would be switching all live poles .

A 240 <

---

> 240 isolating transformer & under/over relay would be nice since you'd never know what effort of a generator would get plugged into it

Reisers

2011 wrote: »

That doesn’t even make sense.

Dual voltage portable generator with 2 110v windings in series

gctest50

Reisers wrote: »

maybe standard in the sailing or boating forum but has no relevance here ...........

Good example of a non-obvious thing though:

if a boat is hooked up to a dodgy shore power,
( or it's generating it's own power onboard and it's a bit iffy )

the prop may become live compared to the rest of the shoreline

So if someone swims near the boat the will become paralysed in the water and drown

Is why electrofishing works so well :

2011

Reisers wrote: »

I was called out to a changeover switch

There was N-E faults on the lighting circuits draining the generator with nothing switched on.

A neutral to earth fault on a generator can not cause the "draining" of a generator.

When I challenge this your response is "Dual voltage portable generator with 2 110v windings in series". I am going to assume that this is an answer to another question as it makes no sense in this context

Steve

gctest50 wrote: »

Good example of a non-obvious thing though:

if a boat is hooked up to a dodgy shore power,
( or it's generating it's own power onboard and it's a bit iffy )

the prop may become live compared to the rest of the shoreline

So if someone swims near the boat the will become paralysed in the water and drown

Is why electrofishing works so well :

Sorry, that's just beyond ridiculous.

All marine shore power supplies are RCD protected for a start. No Marine installs use the prop as an earth, they purposely avoid it as it only adds to electrolysis on the prop annode and cause it to degrade quicker.

Stoner

All the thread is becoming a little derailed. It's in danger of falling into oneupmanship territory.

Can we at least back up our statements before making new ones so as to address the OP in a constructive way.

Reisers

2011 wrote: »

A neutral to earth fault on a generator can not cause the "draining" of a generator.

When I challenge this your response is "Dual voltage portable generator with 2 110v windings in series". I am going to assume that this is an answer to another question as it makes no sense in this context

I thought it was self explanatory

If a genset supply was 110-0-110 and you connect it to an installation with N-E faults.

On the Esbn and domestic changeover switches.My recollection was they insisted on isolating both poles back in the day.
It may have been a rural thing as the neutral wasn't always reliably at earth potential.

Fair enough they're no longer involved.

Bruthal

Reisers wrote: »

If a genset supply was 110-0-110 and you connect it to an installation with N-E faults.

How would it work connected to a neutralized installation then?

Reisers

Bruthal wrote: »

How would it work connected to a neutralized installation then?

It won't unless the supply neutral is broken at the switch

Bruthal

I better stick to carpentry I think.

2011

Reisers wrote: »

I thought it was self explanatory

Definitely not.

If a genset supply was 110-0-110 and you connect it to an installation with N-E faults

....and that “drains” the generator?

Do you not think the generator would simply trip ?