Generator Earthing

[Richardcn]

I think you're overcomplicating it and confusing yourself somewhere along the lines.......I don't know where though.

Very possibly but I am going to try to get to the bottom of it. Let's try one at a time, although I must go soon:

 

1) Is it possible (or likely) that a genny of this type (ie floating earth) could have its (unused/unrequired) output earth pin and its chassis earth connected by design?

 

Richard

[Richardcn]

2) If not then I understand how the genny earthing should be implemented. I don't understand why I am getting a positive reading on my multimeter when I connect between genny output earth and chassis earth.

 

Richard

[Richardcn]

In the meantime a reply from Kipor already!

 

Quote

A difficult question when used on shore an earth neutral bond and compulsory earth spike is ideal. When used on the boat what do we earth to? If it was the boat chassis then if there was a fault you potentially suffer a shock as you stepped off the boat. So on shore an earth neutral link but afloat probably not.

Regards

 

Sent from REB Small Plant Home of the Kipor UK Service Centre

Unquote

 

I will respond to them as soon as I can and clarify hull earthing and RCD etc.

 

Richard

[by'eck]

Very possibly but I am going to try to get to the bottom of it. Let's try one at a time, although I must go soon:

 

1) Is it possible (or likely) that a genny of this type (ie floating earth) could have its (unused/unrequired) output earth pin and its chassis earth connected by design?

 

Richard

 

Not only possible but highly likely as suggested way back in this thread. TBH I don't see why you find this so surprising since it allows the generator chassis to be connected to the boat hull. Would you be happy holding an old style Black & Decker drill with metal casing in your hand if you had any doubt it wasn't earthed?

[by'eck]

In the meantime a reply from Kipor already!

 

Quote

A difficult question when used on shore an earth neutral bond and compulsory earth spike is ideal.

Only if an RCD is fitted downstream otherwise you are engineering a more dangerous system

 

When used on the boat what do we earth to?

The steel hull

 

If it was the boat chassis then if there was a fault you potentially suffer a shock as you stepped off the boat

Only if there was a fault and generator was earthed with ground spike ashore, there was a neutral/earth strap and boat hull was NOT bonded to genny protective earth. Same scenario as shore power.

 

. So on shore an earth neutral link but afloat probably not.

More likely the reverse although optional.

Regards

 

Sent from REB Small Plant Home of the Kipor UK Service Centre

Unquote

 

I will respond to them as soon as I can and clarify hull earthing and RCD etc.

 

Richard

 

I can only suggest that the documented requirement for both installed onboard generators and inverters is that a neutral/earth strap should be fitted at the device followed by an RCD, should give you a better guide than the one received from Kipor.

[Richardcn]

Not only possible but highly likely as suggested way back in this thread. TBH I don't see why you find this so surprising since it allows the generator chassis to be connected to the boat hull. Would you be happy holding an old style Black & Decker drill with metal casing in your hand if you had any doubt it wasn't earthed?

I found this 'so surprising' a) because I know nowt about electrickery I had read elsewhere that the two were most certainly NOT connected and c) because I thought that is what was being implied at times in this thread d) I've never used a portable suitcase generator before and thus then a,b & c

 

Okay next step.

 

3) If the two are 'highly likely' always connected then why is one end of that earth 'path' within the generator better than the other. And when say why I genuinely mean WHY (as I am ignorant of these things). To me it seems that either 'end' (chassis stud or outlet pin) would do and provide the same, although I understand that one would be direct to the hull earth and the other would be via other equipment (the inverter/charger in my case I suppose).

 

Richard

[Richardcn]

I can only suggest that the documented requirement for both installed onboard generators and inverters is that a neutral/earth strap should be fitted at the device followed by an RCD, should give you a better guide than the one received from Kipor.

Yes I too was disappointed by their reply but I will persist with them and provide them with any information that they need in order to give them the best chance of giving a 'definitive' reply, even if that means scenario by scenario! They are, after all, the authority on their product and should provide clear advice on how to use it!

 

Richard

[by'eck]

I found this 'so surprising' a) because I know nowt about electrickery I had read elsewhere that the two were most certainly NOT connected and c) because I thought that is what was being implied at times in this thread d) I've never used a portable suitcase generator before and thus then a,b & c

 

Okay next step.

 

3) If the two are 'highly likely' always connected then why is one end of that earth 'path' within the generator better than the other. And when say why I genuinely mean WHY (as I am ignorant of these things). To me it seems that either 'end' (chassis stud or outlet pin) would do and provide the same, although I understand that one would be direct to the hull earth and the other would be via other equipment (the inverter/charger in my case I suppose).

 

Richard

 

The output earth on the socket and the chassis earth connection are one and the same electrically as you have found. The chassis earth point allows a ground spike to be attached easily when deemed neccessary.

[Paul C]

Let's get one thing straight, where are you planning to site the generator when its in use? It MUST NOT go on a boat deck, or roof, because the exhaust gases will sink and possibly enter the cabin (risk of CO poisoning). So...the obvious place is on the shore/bank beside the boat.

[Loafer]

Is all this thought and complexity required when one's generator ONLY supplies a battery charger? That is our situation.

 

Our batteries then feed an inverter which powers the boat.

[Paul C]

Yes - because you only need to die once, to spoil your day/week.

[Loafer]

Yes - because you only need to die once, to spoil your day/week.

 

Well after 11 years of living aboard, we haven't died yet. It will probably happen, but it won't be from an electric shock on our boat, otherwise we'd already have had them!

[Paul C]

 

Well after 11 years of living aboard, we haven't died yet. It will probably happen, but it won't be from an electric shock on our boat, otherwise we'd already have had them!

 

Yes but other people use more sophisticated techniques to stay safe than the binary test of "I'm still alive today so its okay".

[Loafer]

Can you explain how I could be killed by a generator feeding only a battery charger? What if I didn't have an inverter? Neither of these pieces of equipment has any warnings that I can see!

[Paul C]

Can you explain how I could be killed by a generator feeding only a battery charger? What if I didn't have an inverter? Neither of these pieces of equipment has any warnings that I can see!

 

By heart attack through electric shock from a wiring defect. The number of devices isn't the critical factor, its the voltage. Its also true of those small inverters, people use them and think because its just used for 1 mains device, or because its small, its safer. Its the voltage which is the danger.

[Richardcn]

The output earth on the socket and the chassis earth connection are one and the same electrically as you have found. The chassis earth point allows a ground spike to be attached easily when deemed neccessary.

Marvellous! I do like definitive statements when the subject has meant there are so few to be found

 

Sincere thanks for sticking with me through this, for those that have

 

Richard

[Loafer]

 

By heart attack through electric shock from a wiring defect. The number of devices isn't the critical factor, its the voltage. Its also true of those small inverters, people use them and think because its just used for 1 mains device, or because its small, its safer. Its the voltage which is the danger.

 

At risk of becoming tiresome, I still don't get it.

 

My genny is plugged into the boat's shore power socket, sure.

 

From there, it goes to the boat's distribution board via standard RCD and 'polarity error' light.

 

From the RCD there is only one power lead and that ONLY feeds a Sterling battery charger. I am struggling to see from where I might get a lethal shock.

 

Can you enlighten the dark part of my brain?

 

 

EDIT: So sorry, I got that wrong. I'll leave it there for those who already read it.

 

I should have said that the genny output goes directly to my battery charger.

 

The INVERTER output goes around the boat's AC via an RCD.

Edited March 9, 2016 by Loafer

[Richardcn]

Well after 11 years of living aboard, we haven't died yet. It will probably happen, but it won't be from an electric shock on our boat, otherwise we'd already have had them!

I guess one could apply the same rule to life in general then. As I haven't died yet then I won't die in the future! Unfortunately though, as we all know only too well, things do change and often without us noticing. I guess the presence of the RCD in our boats is recognition of that fact with regards to this topic.

 

Richard

[Loafer]

I guess one could apply the same rule to life in general then. As I haven't died yet then I won't die in the future! Unfortunately though, as we all know only too well, things do change and often without us noticing. I guess the presence of the RCD in our boats is recognition of that fact with regards to this topic.

 

Richard

 

I didn't really mean that generally. I meant it in our case - see the post above yours.

[Richardcn]

The output earth on the socket and the chassis earth connection are one and the same electrically as you have found. The chassis earth point allows a ground spike to be attached easily when deemed neccessary.

So, in answer to my question then, is one 'end' of this 'common' earth better than the other end then (as opposed to providing a more readily available point to attach to)?

 

If the answer to the above is unequivocally 'yes' and 'the earthing stud' then surely that makes the whole idea of a bonded N/E lead redundant as the stud provides the better earth. I am willing to accept that but there are a whole host of people out there (Honda included it would seem) who are advocating the opposite.

 

The point I am trying to make here is that nobody seems to know the right way to do this and that is frustrating and unacceptable. These are people's lives potentially being put at risk through lack of coherent advice, or just total lack of advice from some sources. And for those of you that are happy to keep your heads in the sand 'because I'm not dead yet' (no disrespect intended to you Loafer, you just came along at the right/wrong moment ) and there are plenty out there from what I've seen and heard, then that is your choice of course. I for one could not live with myself if I were to allow a situation to develop in which I injured someone else, especially a child for instance, purely through failing to seek out an answer to a question that I knew HAD to be asked.

 

Apologies for 'getting all serious' but I am really surprised that this issue doesn't ever appear to have been pinned down. It seems like all of the different possible ways of doing this are being done but without good reason in most cases, the most prevalent being 'plug and play' and worry not!

 

Apologies

Richard

[Richardcn]

I didn't really mean that generally. I meant it in our case - see the post above yours.

Yeah no worries My response is still valid though I think. To state the one will not suffer an outcome because one has not suffered it in the past is surely, when discussing lethal risk, bordering on foolishness, or am I misreading your comment? Apologies if that is the case.

 

Richard

[Loafer]

Yeah no worries My response is still valid though I think. To state the one will not suffer an outcome because one has not suffered it in the past is surely, when discussing lethal risk, bordering on foolishness, or am I misreading your comment? Apologies if that is the case.

 

Richard

 

No apologies necessary. My comment was a bit wide-sweeping, but was supposed to be confined to our generator-to-battery-charger-only set up.

 

All happy here.

[Paul C]

In response to post #95 - Nope - for the same reasons as previously. You're muddling the various earth connections, with the need to bond N-E. The requirement to bond N-E DOES NOT become redundant depending on which earthing point you connect to.

[Loafer]

Nope - for the same reasons as previously. You're muddling the various earth connections, with the need to bond N-E. The requirement to bond N-E DOES NOT become redundant depending on which earthing point you connect to.

 

Was that for me, Paul?

[Paul C]

As far as "which earth should I connect to" basically, ALL external metal parts should be connected to earth, ie generator frame, metal light switches, copper water pipes, gas pipes, radiators, etc etc. "Equipotential bonding".

So, in answer to my question then, is one 'end' of this 'common' earth better than the other end then (as opposed to providing a more readily available point to attach to)?

If the answer to the above is unequivocally 'yes' and 'the earthing stud' then surely that makes the whole idea of a bonded N/E lead redundant as the stud provides the better earth. I am willing to accept that but there are a whole host of people out there (Honda included it would seem) who are advocating the opposite.

The point I am trying to make here is that nobody seems to know the right way to do this and that is frustrating and unacceptable. These are people's lives potentially being put at risk through lack of coherent advice, or just total lack of advice from some sources. And for those of you that are happy to keep your heads in the sand 'because I'm not dead yet' (no disrespect intended to you Loafer, you just came along at the right/wrong moment ) and there are plenty out there from what I've seen and heard, then that is your choice of course. I for one could not live with myself if I were to allow a situation to develop in which I injured someone else, especially a child for instance, purely through failing to seek out an answer to a question that I knew HAD to be asked.

Apologies for 'getting all serious' but I am really surprised that this issue doesn't ever appear to have been pinned down. It seems like all of the different possible ways of doing this are being done but without good reason in most cases, the most prevalent being 'plug and play' and worry not!

Apologies
Richard

Nope - for the same reasons as previously. You're muddling the various earth connections, with the need to bond N-E. The requirement to bond N-E DOES NOT become redundant depending on which earthing point you connect to.

 

Was that for me, Paul?

No

The point I am trying to make here is that nobody seems to know the right way to do this and that is frustrating and unacceptable.

 

You've been given good advice from people who DO know. To clarify:

 

1. Forget about someone else's generator, or inverter.

2. You've tested yours and determined that its not centre-tapped

3. You've also tested that the generator earth stud (and its chassis/frame) is connected to the PE

4. You MUST create a N-E bond YOURSELF

5. (4) MUST NOT be connected when you're on shoreline

6. Generator chassis/frame SHOULD be connected to earth too, but this has already been done in (3)