# Reverse Polarity



## vidal999 (May 25, 2007)

When connecting the Motorhome up to a Honda 20i generator, the Reverse Polarity light comes on on the Sargant control panel, just wondered if this is going to cause a problem ,or is it safe ? :roll:


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## PlanetGen (Feb 12, 2009)

Hi, this happens on all vans that were made after 2008. The Generators have to be earthed (eg connected some decent cable to something like a tent peg.) Kept happening to one of my dealers on his Kontiki and they said this is a common fault that is fixed by earthing the Gennies.
Hope this helps
Simon


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## Broom (Oct 8, 2007)

Hi Vidal

Its nothing to do with earthing its due to split voltage instead of having a neutral earth, everything is OK and theres nothing to worry about it happens with mine.

Simon

Can you advise which College or University you attended and courses passed to gain your position on advising others on electrical services, you have raised my concerns previous with your comments.

Best Regards
Adrian


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## Sargent (Feb 1, 2008)

Hi Vidal, as broom has already commented on, it is perfectly safe to use, the light is illuminated because of the way some generators are constructed, with, as Broom as said "split voltages" (110-0-110v) which give rise to the light being illuminated.

If you have any further queries regarding this matter, then please do not hesitate to contact me.

Best regards

Ian Sargent


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## PlanetGen (Feb 12, 2009)

Hi Adrian, all I ever do is try and pass on advice or things I have learned. Surely this is what MHF is for?? In regards to my Qualifications that actually has nothing to do with you. 
At Planet Generators we have people here that are able to work on a Board Level with all types of Generators. We also use a technician that has been in the industry for 25 years.
In regards to the earthing issue. My Northen dealer (Motorama) had the same problem with his Kon-tiki to which he rang Kon-tiki and they advised him. A Generator should always be Earthed (ok some people dont)
Simon


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## RogerAndHeather (Dec 23, 2007)

PlanetGen said:


> A Generator should always be Earthed


via a tent Peg?

I don't want to be rude


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## JohnsCrossMotorHomes (Jul 21, 2007)

RogerAndHeather said:


> PlanetGen said:
> 
> 
> > A Generator should always be Earthed
> ...


I think he means a big METAL tent peg!

Peter


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## PlanetGen (Feb 12, 2009)

Hi Peter, common sense needed there! Obviously I mean As long as it is earthed on a steel or even a copper spike driven into the ground would act as a suitable earth pin.

As a general rule for small leisure generators, it is normally advisable to use a earth spike 10 inches in length per 1000watts, through a 4mm earth strap.

As for qualifications, we have retained the services of a Power generation specialist who is certified to service gensets as large as 1.2Mw and holds a current 16th edition certificate.
Simon


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## karlb (Feb 22, 2009)

DO NOT EARTH YOUR GENERATOR IF YOU DONT KNOW WHAT YOUR DOING!!!

http://www.justgenerators.co.uk/pages/FAQ.htm


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## thePassants (Feb 9, 2009)

PlanetGen said:


> ...and holds a current 16th edition certificate.
> Simon


There is nothing _current_ about the Sixteenth Edition (apart from the obvious pun) !

- do keep up!

;o)


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## PlanetGen (Feb 12, 2009)

Hi Karlb

That is an exercise I could not, in good conscience advise, If, and I do emphasise, IF, the generator was to short circuit, one could end up with the chassis of their motorhome live with 240Vac as the motorhome is insulated from ground by the tyres (large amounts of rubber, which is an excellent insulator)

This voltage surge could do damage to the 12vdc circuits and batteries.

On any generator, there will be an earth lug, It is advisable to use this and earth the generator before starting it.

It is there for a reason, for your safety. I can only and would always advise that it is used.

Simon


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## RogerAndHeather (Dec 23, 2007)

PlanetGen said:


> As a general rule for small leisure generators, it is normally advisable to use a earth spike 10 inches in length per 1000watts
> Simon


This means that I need to hammer nearly 3 feet of metal into the ground every time I stop and use the generator....... :evil: .....I take back what I said about the tent peg


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## PlanetGen (Feb 12, 2009)

I think this thread has gotten a bit out of control. 

As a rule, it is best advised to use a ground spike, It's not always feasable to use a large earth spike for a small leisure generator. A three foot spike is normally suitable for a 115kva genset, this depends on ground conditions, and load.

I have given advice, it can be used or cast aside, advice is still for free, I would advise any customer to utilise the largest earth spike possible, as a persons personal safety and the safety of their family is paramount.


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## Broom (Oct 8, 2007)

Hi Simon 

We are up todate working to the 17th Edition of the regulations.

Best Regards
Broom


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## thePassants (Feb 9, 2009)

*terra terror*

Since the vehicle is insulated from Earth so well (as was mentioned earlier), surely it too would benefit from an earth electrode?

However, if the generator has an earth terminal; which is also 'Earthed' by an electrode, then they may as well be directly connected to each other...?

But, the generator (from that link mentioned earlier too), may be 'centre tapped to earth': producing -115v / 0v / +115v (for N/E/L) =230v L/N.

Now, this sounds like potential trouble to me in the context of inverters (and mains supplies) with Neutral & Earth bonded supplies...

-anybody?


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## PlanetGen (Feb 12, 2009)

We are up todate working to the 17th Edition of the regulations. 

Would you, in good faith and business practice, advise customers not to use an earth spike?

You may question my advice, but at least I am prepared to give advice on things that I can help on.

Simon


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## spindrifter (Nov 14, 2006)

Where's the eath wire going???

http://www.hondapowerequipment.com/products/generators/content.aspx?asset=gg_parallelcapability

David


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## Broom (Oct 8, 2007)

Simon

In short you have previously advised and made some not quite correct statements, I have just brought this to the attention of our members who quite agree I am sure.

Ste

First hows the screens 

I would use a spike to earth the frame of the generator and protect the Motorhome via RCD, it would be best if the RCD was at the generator, but generally this is not the case.

Best Regards
Broom


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## PlanetGen (Feb 12, 2009)

Hi Broom please advise so I know for next time?


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## Broom (Oct 8, 2007)

Hi Simon

Better I keep an eye on you and remind you.

Signing off now best regards
Broom


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## RogerAndHeather (Dec 23, 2007)

Hi thePassants,

I suppose this thread is veering off-topic enough to warrant a reply to your post. I remember years (and I do mean years) ago to sub-consciously listening to lectures about 'star coupling' on transformers and stators and all that stuff. Maybe I should have listened a bit more and be able to contribute a bit more sense.

I don't really understand where the earth and neutral bonding is an issue as it should not be apparent with equipment designed for use on a mains supply - i.e. there should not be any bonding in the design. 

To me, the safety issue with the earthing of generators falls into the same safety category of reversed polarity. There have been a lot of posts on the subject(s) and doing a search brings up so many contradicting advice that it could be construed as a safety issue in itself.

How about MHF taking the lead and commissioning a bit of independent research into the issues. I would be quite happy to pay an extra £1 next year to have a good '18th edition' of MHF regulations aimed specifically at us. £32,000 should give us a good document!

Cheers, Roger


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## Broom (Oct 8, 2007)

Hi Roger

Are you aware in the new regulations just issued there is a full section on motorhomes/caravans, I think its been done already.

Best Regards
Broom


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## thePassants (Feb 9, 2009)

*Terra terror & Regs*

Hi Broom, Roger & all;

Section 721; not going to win any 'plain english' awards is it?
-so many references to other sections and so on: I've had a good look at it the last time 'inverters' and earthing came up, not particularly plain reading eh?

The previous section seemed more relevant to Motorhomes set-ups in a way: vehicles with generators or mobile workshops or something (the book is in the van and I can't remember)

Anyway; on a recent job, where the house had no supplied earth & I got United Utils out to it; they took them off supply until they could fix the problem.
I asked the engineer about earthing the (honda) generator he connected as a temp. supply.
He told me you didn't need to. (but I'm sure it had a terminal to connect one from)

[What was puzzling me about the 115/0/115 thing is that bonding N to E would short one of the coils, surely?]

---Oh how we love runaway topics---

(BTW Broom; you've a PM)


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## Broom (Oct 8, 2007)

Hi Ste

You have not got a N to E bond as such, the inverter/generator is centre taped to earth and voltage on each leg, that is where the RCD comes in to play protecting the load.

Best Regards
Broom


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## RogerAndHeather (Dec 23, 2007)

Hi again

I'm sorry that I was just being silly about using the '18th' for MHF regulations.

I have just PM'd nuke, public it may be............

Hi Nuke, we haven't talked before, so, hello. 

Sorry if this is a bit brief but it is getting a bit late for me. Could you take a look at the forum subject 'Reverse Polarity', this type of subject is rearing up all the time, there is always a bit of agro, and some of the advice could construed as dangerous if acted on. 

MHF now has in excess of 32,000 members and could we not afford to commission some independent, professional research into these safety matters and come up with a definite package of advice to members. I have stated on that thread that I would be willing to add another £1/year to finance that sort of thing, I bet others would agree. 

Please have a think about it???? It could be the icing on your cake!!! 

............................ 

I do feel that we need to tie these safety matters down and comments like using tent pegs for earthing generators only degrades forums like this.

As a fee paying community, we should provide a high quality, comprehensive, independent FAQ service to members. Discussion should be free for all to contribute, but safety should be defined to one place and all discussions should be able to reference that definitive point.

Sorry for the rant, I do get upset at times.


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## thePassants (Feb 9, 2009)

RogerAndHeather said:


> ...commission some independent, professional research...


- seconded.
The NICEIC might be able to help us here?


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## gaspode (May 9, 2005)

The subject of neutral/earth bonding has been discussed in the forum many times in the past both in respect of generators and inverters. Although in possession of some electrical expertise myself I've never been able to come to a positive conclusion on a "correct" (and practical) procedure that fits every situation.

We do have members here who are among the best experts available on the subject, maybe one of them would like to submit an article to the new FAQ section so we can all benefit from the latest thinking on the subject?

If past experience is anything to go by, the "experts" are unlikely to reach a concensus easily. 8) 

In the meantime, can we please maintain a polite and measured approach to the discussion? Most members here contribute their advice to the best of their knowledge and ability and whilst I agree that inaccurate advice should be brought to our attention, there is no need to do it in a way that causes offence to anyone.


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## RogerAndHeather (Dec 23, 2007)

I'm sorry gaspode but you sound a bit like 'Gorbal's Mike' :roll: here

Where have your experts been hiding? Any newcomer to the MHF could have a nasty experience by doing a search on this topic.

My suggestion is that we have a comprehensive, profesional, FAQ on safety topics which would do away with the so-called experts reaching a consensus. 

Nobody has been impolite without a sense of humour - how about you?

Roger


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## CliveMott (Mar 10, 2008)

James May has a word for it "Oh Cock" I do believe. 

The IEE regs are at edition 17. 

Generators with a single power outlet and connected to a single piece of equipment are best used totally isolated. i.e. no earthing of any part of the supply. The logic behind this is that you will need two earth faults at different potentials to cause an earth current to flow and with one piece of equipment which will be regularly maintained and checked this is very unlikely. 

However 

When the generator is used to power more than one bit of equipment (like several bits inside a motorhome) then a different scenario exists. If the generator output is fully isolated then the first earth fault could be for example between the LIVE connection and the EARTH connection inside an electric water heater. With no earth bonding this would not be detected by any circuit breakers, no one would get a shock and everything would continue to operate normally. The reverse polarity indicator in the Sargent unit would be glowing just as brightly as it was beforehand. Now consider the hair curlers that your wife is about to plug into another socket in the van, when these warm up something distorts and cause a short between the handle and the Neutral connection. Now an earth fault current can flow, perhaps through your wifes hand, up the other arm and hand which is resting on the stainless steel sink. This being a fully compliant van will have the sink bonded electrically to earth. This fault current then flows through the vans earth wiring to the water heater where it completes its circuit back to LIVE via the first earth fault. Now none of this earth current actually causes any unbalance in the currents flowing in the vans RCD so at best your wife shakes until she drops the curling tongs. 

So to ensure maximum safety the NEUTRAL and EARTH connections INSIDE the generator socket should be linked. (This is just the same as your local home sub-station) and a decent earth spike hammered into some damp ground (where the grey water drips out) alongside the generator and connected to the chassis of the generator which should also be connected to the EARTH pin of the socket. 

Now, with the van connected as soon as any earth fault causes some current from the LIVE connection to flow to earth this current will find its way back to the generator neutral via the EARTH wiring. It has not returned via the NEUTRAL pin on the hookup lead and if this current is greater than 0.03 of an Amp the RCD will open and disconnect the supply. 

An earth fault inside the van between earth and NEUTRAL will not be detected as both are at the same potential so its important that the integrity of the vans electrical system is checked regularly. 

Does that help?? 

C. 


Ken - put this somewhere else if you wish.


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## Penquin (Oct 15, 2007)

Thank you Clive for what i believe is a definitive answer - delivered without any bias and in a clear manner. That is very helpful and I will make sure it is retained in case of future need!

I think I am heartily relieved NOT to have a genrator and therfroe not to have to worry about N - E bonding, spikes and so on! :? 

As a non-specialist I know nothing about these regulations and would nver profess to totally understand, like many others I try to act in a safe manner and to follow clear advice - which you have given.  

Dave


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## CliveMott (Mar 10, 2008)

*CLIVE - GENERATORS VERSION 2*

Slept on these words overnight. Hope this is a little clearer.
Clive

The IEE regs are at edition 17.

Generators with a single power outlet and connected to a single piece of equipment are best used totally isolated. i.e. no earthing of any part of the supply. The logic behind this is that you will need two earth faults at different potentials to cause an earth current to flow and with one piece of equipment which will be regularly maintained and checked this is very unlikely.

However 
All modern Motorhomes are equipped with an RCD (Residual Current Device). The RCD monitors the current flowing in the LIVE connection to the motorhome and compares this current with that flowing in the NEUTRAL connection to the motorhome. If these currents differ by more than 0.03 Amp (30 milliamperes) then the RCD will open and disconnect the supply. For these currents to differ when there is an earth fault on a bit of equipment there has to be another path through which that current can flow, this path is provided domestically by the NEUTRAL at the local sub station being connected to EARTH.

When the generator is used to power more than one bit of equipment (like several bits inside a motorhome) then a different scenario exists. If the generator output is fully isolated then the first earth fault could be for example between the LIVE connection and the EARTH connection inside an electric water heater. With no earth bonding this would not be detected by any circuit breakers, no one would get a shock and everything would continue to operate normally. The reverse polarity indicator in the Sargent unit would be glowing just as brightly as it was beforehand. Now consider the hair curlers that your wife is about to plug into another socket in the van, when these warm up something distorts and cause a short between the handle and the Neutral connection. Now an earth fault current can flow, perhaps through your wifes hand, up the other arm and hand which is resting on the stainless steel sink. This being a fully compliant van will have the sink bonded electrically to the vehicle chassis and the Motorhomes earth wiring. This fault current then flows through the vans earth wiring to the water heater where it completes its circuit back to LIVE via the first earth fault. Now, none of this earth current actually causes any unbalance in the currents flowing in the vans RCD so at best your wife shakes until she drops the curling tongs.

So to ensure maximum safety the NEUTRAL and EARTH connections INSIDE the generator socket should be linked. (This is just the same as your local home sub-station) and a decent earth spike hammered into some damp ground (where the grey water drips out) alongside the generator and connected to the chassis of the generator which should also be connected to the EARTH pin of the socket.

Now, with the van connected as soon as any earth fault causes some current from the LIVE connection to flow to earth this current will find its way back to the generator neutral via the EARTH wiring. It has not returned via the NEUTRAL pin on the hookup lead and if this current is greater than 0.03 of an Amp the RCD will open and disconnect the supply.

An earth fault inside the van between earth and NEUTRAL will not be detected until some electrical load is turned ON as both are at the same potential however as soon as some load is applied the current intending to flow back to NEUTRAL now has an alternative route via the EARTH wiring and some will flow that way. Again the RCD will detect the unbalance and switch off.
With generators that have the chassis / earth connection connected to a centre tap of the output this again will provide a return path for earth fault currents via the earth wiring thus causing the currents through the RCD to be unbalanced resulting in it switching off.
The importance of having an earth spike is because the generator is normally outside and you may just be using an extension lead from the van to power something outside the van.

Does that help??


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## AberdeenAngus (Jul 26, 2008)

The reason there are differences of opinion, even between experts, is that all protective devices offer a "reduction" in risk - not complete safety. 

You can bet that the bigger the arguement, the smaller the benefit they are arguing about.

Comparing the effort of driving in an earth spike every time I stop, against the benefit gained ........I, for one, won't bother.

Do you expect to live forever ?

I also use industrial waste grade hose to fill my water tank.

....so there !


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## BJT (Oct 31, 2008)

Clive is correct. current edition of the IEE Regulations is technically now BS 7671:2008.
In part 7 there is a new section 721, which covers - Electrical installations in caravans and motor caravans - previously in Section 608 of BS 7671:2001.
The section covers 10 pages, but cannot be reproduced in full for copyright reasons. It covers both 240 volt AC, and up to 48volt DC.

Generator sets are covered by Section 551, earthing specifically 551.4 - fault Protection.

One note - Fig 721 contains (almost as an afterthought) last paragraph - 
Periodic Inspection.
Preferably not less than once every three years and annually if the caravan is used frequently, the caravan electrical instasllation and the supply cable should be inspected and tested and a report on their condition obtained as prescribed in BS 7671 Requirements for Electrical Inatallations published by the Institution of Electrical Engineers and BSI.

So, for most motorhomes an annual test and inspection by an electrician holding the appropriate certificate of competency is now a specific requirement. Failure to get you MH checked might infringe the small print in your insurance policy!! More expenditure needed methinks.

Hope this is of some use. I have the said BS beside me as I trype this.

TTFN


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## nukeadmin (Oct 10, 2003)

> I would be willing to add another £1/year to finance that sort of thing, I bet others would agree.


lol sorry but I think you are sorely mistaken there as to the numbers of members who would be willing to add an extra £1 to subs to fund research into this  If we started along that road would we then add another £1 to fund research into Gas attacks or Towing behind a motorhome and the other too numerous to mention grey areas with motorhomes

I think this thread emphasis one thing and that is there isn't always a strictly black and white answer. Planet Generators are answering the thread from a traders view i.e. they have to give the Safest advice albeit probably not the most practical, but as Clive has shown this seemingly over the top advice of hammering in earthing points every time you use your generator could potentially be life saving (given a series of events)

You will never get a definitive answer I am afraid, the only thing I would add is in my experience for 2.5 years full timing with a Honda Generator is that I never used an earthing point and had no issues and now with a Kipor or Planet Generator I would probably still do the same as the extra work involved Vs the actual risk incurred would mean I wouldn't bother. That said as a responsible operation we should say that Clives/Planets advice would appear to be the safest option out there.


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## RogerAndHeather (Dec 23, 2007)

nukeadmin said:


> > If we started along that road would we then add another £1 to fund research into Gas attacks or Towing behind a motorhome and the other too numerous to mention grey areas with motorhomes
> > .
> 
> 
> ...


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## autostratus (May 9, 2005)

RogerAndHeather said:


> ..Surely the £1.00 would cover the major areas and maybe could be financed from the current subscriptions with the number of members now registered. MHF is already a great service, let us take it even further down the road.
> 
> Roger (still half asleep)


Sorry, Roger but the number of members registered bears little relation to the number of subscribers.


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## eddievanbitz (May 1, 2005)

From the outside looking in, I think Rogers idea is a great one, however like lots of great ideas not practical

Thirty odd thousand members, of which a few subscribe. 

The majority don't give a toss about reversed polarity, gas attacks, the poor build quality of RV's The OTT price of German vans sold in the UK in comparison to the price in Europe or frankly pretty much anything that is a burning issue to the person writing or starting the thread, that drops off the page like a stone! Because no one else shares their passion or interest!

Also getting things agreed! Simon has suggested earthing a generator! and got criticised for suggesting a tent peg! No one stopped to ask how big a tent peg! The ones that Simon has grown up with are about 18 " long and are about 1/2 in diameter! Most people before reading this thread didn't even know that they are supposed to earth the genny before use (Yes even the built in ones on Yanks!) So his advice wasn't completely wrong, but at least some will have learnt something.

We as a company supply loads and loads of equipment. Our expertise is in the installation of equipment, we rely on the manufacturers to advise us how to install and operate the equipment they have designed and built. We expect them to have tested and built the equipment to the correct standard and, for it to comply with the current regulations.

However, this does not stop "experts" asking us myriads of questions about products, questions far beyond the usual type of questions that a potential customer would ask or know to ask, or frankly need to know. We try to discuss the product to the best of our knowledge, get ambushed about a regulation or a build principal an end up reading about ourselves as "incompetent and not knowing what we are talking about" 

We in the trade, cannot be experts on every product that we sell, if we hope to expand our business and give excellent customer service.

I for example opened Cornish Farm Touring Park Easter 2005, I knew very little about campsites and we had to learn as we went along and ran into all sorts of complications. It didn't however stop us from picking up several National Awards along the way for running a fantastic site.

I could of course spent an age learning every facet of building and running a campsite before starting, only to find out that all the rules had changed before I started and would have to go back and revise everything I had learnt! 

Talking to "experts" this seems to happen a lot, which is where consultants come from :lol: 

There is a famous quote "Anyone who has never made a mistake has never tried anything new.’


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## TR5 (Jun 6, 2007)

No matter how much you funded research, there would always be someone who would argue the point.

Take Tax & Politics, as a prime example!


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## CliveMott (Mar 10, 2008)

*RECENT EXPERIENCES*

A little bit of background

The regs are a minefield.

I recently had to assemble some kit for our local Ham radio club to power 4 contest radio stations that we operate from a field on top of a hill. All the stations are powered from a trailer mounted Lister diesel powered 3 KVA generating set. Last year one station was in the awning of a caravan. It was blowing a hooley and raining like there was no tomorrow. In one big blow the awning took off over the caravan and left the operators with all their mains powered gear sat in the rain. After this some questions were asked about safety and one cannot ignore this. I made several telephone calls to the offices of the IEE for advice and guidance. Plenty given but all over the phone. No one would put anything in writing as everything had to be interpreted and no one wanted to take any responsibility. (I did note the names though) 
So, I have researched this matter at some length in recent months.

The Camping and Caravanning club publish a leaflet regarding temporary installations and this is a very good guide for anyone with a generator. Anyone attending the NEC in October of February and staying on the temporary camp site should have been given a copy.

The problem with risks is that you don't see coming those that hurt.

Clive


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## krull (Jul 22, 2006)

BJT said:


> One note - Fig 721 contains (almost as an afterthought) last paragraph -
> Periodic Inspection.
> Preferably not less than once every three years and annually if the caravan is used frequently, the caravan electrical instasllation and the supply cable should be inspected and tested and a report on their condition obtained as prescribed in BS 7671 Requirements for Electrical Inatallations published by the Institution of Electrical Engineers and BSI.
> 
> So, for most motorhomes an annual test and inspection by an electrician holding the appropriate certificate of competency is now a specific requirement. Failure to get you MH checked might infringe the small print in your insurance policy!! More expenditure needed methinks.


A classic case of someone adding 2 and 2 and getting 5. What legislation states that your m/h must comply with the 17th edition?


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## 117442 (Oct 14, 2008)

GN3 (testing guide to BS7671) does indeed advise annual checks for frequently used vans. Working as the electrical projects engineer for local council, a recent project has been the upgrading of a travellers site electrical installation. It has been a real eye opener what I’ve seen then, and generally beggars belief, with a lack of any records of van or connection lead tests being one of the relatively very minor issues. Perhaps I’ll write a chapter about it one day in my memoirs! It’s almost as bad as a very large National Health hospital that I surveyed all the plant and services for a couple of years ago, but that would take a full volume of books to detail in my memoirs!
As for generators, plenty of industrial and power station experience with them over the years, and even now, always look at manufacturers recommendations and sketch out circuits for my own satisfaction. Some good advice seen here, but be aware, some centre tapped outputs may already be earthed at the centre tap, so really does pay to check the manufacturers data, as do need to ensure that the supplementary protection provided by the RCD will function correctly.


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## BJT (Oct 31, 2008)

In response to krulls' query; you need to look at the small print on your insurance.
It is no good moaning if they refuse to pay out on a claim if any annual maintenance or checks specified in the policy have not been done. By this I mean that the relevant piece of paper cannot be produced habitation, damp,gas checks; and now electricity.
Note that the Regs are not retrospective, if the van is pre 2008 it probably complies with 7671-2001 and so this specific requirement does not directly apply. However, if work of any significance is carried out and a new certificate, or instruction label, indicating compliance with BS 7671-2008 then the requirement comes into force.
Vans completed during 2008 will at some point have changed from 2001 to 2008 edition specification; and for these it is recommended to have the inspection done. As stated before, failure to get such inspections done may infringe insurance policy requirements. So, check your policy and the vans original electrical certificate.


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## 106559 (Aug 19, 2007)

So,,,,, when I start up my wee 1,000 kipper to charge my battery should I earth it or not? :? I don't need to know how it works I only need to know how to work it.

Be gentle please! :?


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## CliveMott (Mar 10, 2008)

Well, you have seen all the advice and comments, only you can make a considered risk assesment for your planned usage.

But don't take too long, aparently the Kipor units have a high mortality rate with their printed circuit boards. (So I was told)
C.


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## Broom (Oct 8, 2007)

Hi All

As previously advised and as SDMO/Honda recommendations for the 2000 Inverter Booster, earth down the frame of the generator via the provided bolt, use a 10 mm cable to a 1000mm long earth spike.

Try and fit a 30ma RCD at the generator, if you have a 13amp socket outlet, get one of the plug in type for extension leads.

Use an extension lead as short as possible minimum size 2.5mm X 3 core.

That should at the very least keep you alive.

Best Regards
Broom


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## Hovis (Mar 28, 2007)

When doing National Service it was common practice to "Pee on the Peg"
literally, to get a good earth!!
Hovis


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## BJT (Oct 31, 2008)

Having had a rake around the web I cam across the following information for Honda generators. It may not apply to other makes, so I can only suggest you look at the manual that came with the generator, or visit the manufacturers web-site. But, it does make clear that small Honda generators are designed to operate with a floating earth and do NOT need earthing , but there are a number of FAQs on the site that can provide information for those unsure about generator selection or sizing. Again, it only only refers to Honda, so check other manufacturers for comparative information.

WWW.hondagenerator.co.uk/pages/FAQ.htm


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## Broom (Oct 8, 2007)

Hi All

Please do not try and earth down one of the legs on an inverter generator as BJT's attachment earthing FAQ, I would say that this is referring to a standard type generator set.

I am still for earthing the case of an Honda Inverter Generator via an earth spike

Best Regards
Broom


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## thePassants (Feb 9, 2009)

Well; although the focus of this is now off the original topic of reverse polarity, and has become 'earthing' (again). There is some paticularly clear info posted; particularly (but not limited to that) by Clive.

The only bit I can see to add/clarify is that:

An important distinction to make is that between: a small generatior powering _one_ piece of Class 2 (double insulated -having a symbol of 2 squares inside each other) equipment; and using a generator as the _supply_ for an electrical installation in a motorhome, barge, or as a back-up in a building.

The following refers to construction sites, but the issues are the same:
____________
(advice from the IET, on the Voltimum forum):
A small single-phase generator is often run as a floating system. A means of earthing is not required. In such a system the generator is deliberately not connected to external metallic parts nor is one pole of the single-phase electrical system connected to earth.

In such a system there is no path for an earth fault current to return to the 'separated' winding of the generator. Safety must be ensured by meeting the following conditions:

(a) The generator should be used only on a short term basis (for a maximum of a few days, but ideally, less than one day).

(b) The generator should preferably supply only one item of Class II equipment (See figure 1). Hand-held 110 V (industrial use) or 230 V (domestic use) portable equipment should be Class II construction.
_____________

The additional risks present with a whole _installation_ (with several appliances, and wiring in a partially conductive environment) require proper protective measures (RCD and appropriate earthing arrangements; just like a house), for these to function correctly: for the protection of people inside _and_ outside the vehicle. This includes local earthing using an electrode / peg; as adequately described by others here.

It is because of the inherent safety of Class 2 equipment that it's fine to use it on a 'floating system' *but* obviously the equipment must be appropriate for it's environment: for example IP ratings if used in a wet area.

*Since a motorhome is not a PAT tested, Class2, IP56 appliance; it should not be simply plugged into a generator!*

[As far as compliance with the Wiring Regs (17th or previous editions) goes, raised by Krull; since motorhomes are not 'buildings', the Building Regulations do not apply (despite them being 'dwellings'?) and non compliance is therefore not necessarily a criminal offence, the Electricity at Work Act may still apply in some cases though.
The fact is though that this document (BS7671) is an international benchmark for good practice and is universally accepted. Trying to defend non-observance of it would clearly be difficult, and as previously mentioned by someone; it is not retrospective: ie a '60s installation is only expected to comply with '60s regulations _until_ new work is done; and apart from repairs, this should observe the present edition.]


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## sallytrafic (Jan 17, 2006)

thePassants said:


> Well; although the focus of this is now off the original topic of reverse polarity, and has become 'earthing' (again). There is some paticularly clear info posted; particularly (but not limited to that) by Clive.
> 
> The only bit I can see to add/clarify is that:
> 
> ...


I've kept away from this earthing topic as it can be very involved but I would like to congratulate 'thePassants' on an excellent post.

The only thing I would add is the practise of plugging a generator into the EHU connector on the side of a motorhome is prevalent, I have often seen it done. If the van is wired up to BS standards then the earth point of that connector will be already connected to vehicle chassis which means any exposed metal will also be connected, think cab of a coach built or all of a panel van or all the dc wiring. You now have to really consider risks and know what you are doing if you earth the generator or not. Indeed a small panel van like mine might come under the definition of a 'restrictive conductive location' with all the extra considerations that then apply!


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## SpeedyDux (Jul 13, 2007)

I reckon Motorhomes were simply not at the forefront of the minds of anyone who drafted Regulations or Standards for electrical apparatus. 

That might come as a surprise to some MHers. :roll: 


SD


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## sallytrafic (Jan 17, 2006)

Well I'm rapidly moving towards a no hook up dc only van. I have just done over six weeks without a hook up. This was with moving most days but probably only 2 hours driving per day on average. I do have a 130W panel but it was the north of Scotland.


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## CliveMott (Mar 10, 2008)

"common practice to "Pee on the Peg" 

I peed on an electric fence once!!!!!!


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## pippin (Nov 15, 2007)

I bet that had an effect on your "peg"!!!!!


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## CliveMott (Mar 10, 2008)

I didn,t do it again!

C.


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