Electrical safety

Submitted: Friday, Apr 25, 2014 at 14:06
ThreadID: 107454 Views:3962 Replies:7 FollowUps:18
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Dumb question maybe, but please bear with me.
If you are running a caravan off the grid with a big battery bank and sizable inverter to power the 240V appliances, how do you achieve earth leakage protection using a conventional ground fault interrupt safety switch? Is the only option to bang a copper stake into the ground? Ditto for using a generator?
I can't think of any other way. What do the experts do to avoid frying themselves?
Keith
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Reply By: The Bantam - Friday, Apr 25, 2014 at 15:11

Friday, Apr 25, 2014 at 15:11
The simple answer is you don't.

You can not rely on any of your normal safety devices working AT ALL.

AND

No you should not drive an earth stake either...the wiring rules expressly forbid it.

there are a couple of reasons for this.

1. there is more to an earthing system that driving an earth stake. The average person is incapable of ensuring a good earth connection and everything that goes with it.

2. Importantly, for an earth stake to be of any use at all, there would have to be an earth neutral bond associated with the earth stake.
Neither the inverter nor the caravan will contain an earth neutral bond.....unless the inverter or generator its self contains the earth leakage device.

In general earth stakes and earth neutral bonds are only associated with permanent fixed electrical installations.
As I say there is a great deal more to this whole matter than the earth stake and the earth leakage device.

In our homes and businesses there is a whole regulated environment that extends to everything about the electrical system and the building it is installed in.

Modern fixed install electrical systems have layer over layer of protections against electrical shock that most people are completly oblivious to...BUT take hundreds of pages to specify.

This is why people like me harp on the very real risks assocaited with portable sources of 240V supply.

It is simply not possible to produce the incredibly safe environment we have in our homes and businesses these days in a portable electrical system.

We are left with one and only one systematic protection against electrical shock and that is the floating supply that by design has no ground reference.

The second protection we have is care...when working of portable sources of electrical supply ( inverters and generators ) we must be incredibly carefull.
Carefull about what we do
Carefull about the condition of our equipment.

There is one imporatant measure.
Have only ONE metal cased, non double insulated appliance connected to a poratble source of supply at any one time....if you are connected to a caravan or camper trailer...that is the one metal cassed appliance.
All the rest should be double insulated.

Of course when you connect to a caravan park pillar or a mains outlet at home...you connect to a permanent electrical installation with an earth neutral bond and you are nearly as safe as you would be in your own home.

This is a serious matter and one that plenty of people do not want to hear about.

On the brighter side, there is less and less reason to have 240V mains in a caravan or camper.
So many of the things we use are now normally 12 volt native or can be purcahsed as 12 volt native or can be run via an adaptor off 12 volts.

To my knoweledge there are onlya few devices that can not be run more or less directly off 12 volts...the microwave, the coffee machine being two, the others are mostly womens beauty appliances such as hair driers, and other hair manipulating devices.

cheers
AnswerID: 531191

Follow Up By: K&FT - Friday, Apr 25, 2014 at 15:46

Friday, Apr 25, 2014 at 15:46
There is a new device (approved) on the market that overcomes the issues of leakage fault protection in isolated supplies.

The device is known as an RVD and is marketed by Safelec. I believe it is a completely Australian designed and developed device although I may be corrected if I am wrong there.

have a look here for more info; Safelec

frank
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Follow Up By: The Bantam - Friday, Apr 25, 2014 at 16:36

Friday, Apr 25, 2014 at 16:36
The web site gives no detailed information about how the RVD works, only that it works in conjunction with the existing RCD protection.

from the little that is on the site, it seems that this ADDITIONAL device places an earth leakage current on the RCD that preceeds it to make it trip......yeh well there the problem is.....unless there is an earth neutral bond preceeding the RCD it wont see this deliberate earth leakage current.

The problems with the portable sources of supply is that there is no earth connection to the neutral at the source of supply.

I do not believe there is any device that can overcome this problem.

cheers
0
FollowupID: 814206

Follow Up By: Allan B (Member, SunCoast) - Friday, Apr 25, 2014 at 18:44

Friday, Apr 25, 2014 at 18:44
I am not a champion for the Safelec product but it does have interesting features and is an approved device.

It is applicable to Class 1 appliances which have exposed metal bodies. It has no application to Class 2 appliances which are double-insulated. It operates by monitoring the voltage present on the earthing conductor which is connected to the appliance body and tripping the supply if that voltage exceeds a nominated 43 volts.
It provides no protection from personal contact directly between an Active conductor and the greater body of earth as distinct from the wired earthing conductor. This situation is left to the accompanying RCD to protect the person.

Despite what the Bantam has said above, the principle of operation and essential specifications are on the Safelec website. It operates in conjunction with a standard RCD and in the event of a fault condition isolates the supply by tripping the RCD. This is achieved by causing an imbalance current of 30mA to flow between the RCD's incoming Neutral conductor and the outgoing Active conductor in the same way as the RCD's test button works. It does not rely upon an earth connection nor a system earth/neutral bond for its operation. Accordingly the Safelec product has application in isolated supplies such as inverters or generators where no earth/neutral bond exists.



Cheers
Allan

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Follow Up By: The Bantam - Saturday, Apr 26, 2014 at 22:49

Saturday, Apr 26, 2014 at 22:49
The problem remains ( explain to me why not) that an RCD requires an earth neutral bond on the supply side of the RCD to function.

BY law there is no earth neutral bond in a caravan.

There can be no in ballance and the can be no current flowing in the earth if there is no connection between the neutral and the earth.

There is a vague discription of how the device works on the site but no detailed explanation.

No doubt this device will achive greater sensitivity, particularly under dertain circumstamnces. but it can not possibly protect against an active to neutral shock.
If there is no earth neutral bond and there is no connection with the greater mass of earth.....for all inetents and purposes, there IS no earth........many of the modes of shock become active to neutral paths.

There is just no way arround it.....so much of what we take for granted in the electrical safety in our homes relies on an earth neutral bond and a connection to the greater mass of earth.

NOW..these RVDs may work when the RCD is included in the inverter or generator, because there will be an earth-neutral bond in that generator or inverter.

But if it is a generaotor with no RCD built in there will be no earth neutral bond and the RCD in the caravan will not work.

cheers
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FollowupID: 814299

Follow Up By: Allan B (Member, SunCoast) - Sunday, Apr 27, 2014 at 13:12

Sunday, Apr 27, 2014 at 13:12
Bantam,

I do not wish to contribute to hijacking the original topic and becoming involved in an extensive argument but in the interests of fidelity I will answer you by responding to your points as follows:

1. "By law there is no earth neutral bond in a caravan."
Agreed, and there does not need to be. The Wiring Rules define the specific arrangement of intentional connection between the neutral conductor and earth. In general, this is at one point only in an "installation" at main switchboards. A caravan is not an 'installation' and the distribution board within a caravan is not a main switchboard.
As a generalisation, it is not functionally necessary for an "earth-neutral" bond to be installed in an installation for a RCD to effectively protect. All that is required is an alternate return current path which may be provided elsewhere or unintentionally by a fault connection. Without such path, no current will flow to earth and an RCD will not trip, but then neither can an electric shock occur as no current flows.

2. "There can be no in ballance (sic, read 'imbalance') and the can be no current flowing in the earth if there is no connection between the neutral and the earth."
The original question was in regard to supply from a battery-driven inverter which can be assumed to be fully isolated, i.e. no intentional connection between its live conductors and earth.
In this situation there is no current path and no risk of electric shock due to a person contacting one live conductor and earth. Accordingly, the issue of imbalance does not arise.

3. "There is a vague discription of how the device works on the site but no detailed explanation."
There are technically adequate descriptions of the product on the Safelec website. Your inability to discover them does not mean that they are not there.

4. "No doubt this device will achive greater sensitivity, particularly under dertain circumstamnces. but it can not possibly protect against an active to neutral shock."
No one has claimed that it will protect against active to neutral shock, and incidentally, neither will an RCD or anything else.

5. "If there is no earth neutral bond and there is no connection with the greater mass of earth.....for all inetents and purposes, there IS no earth........."
Certainly, there "IS no earth" as you describe. That is, there is no deliberate connection between a live conductor and earth, but a 'first fault' occurrence can produce such a connection. In this event it is possible for personal contact between the other live conductor and earth to create an electric shock. The presence of a RCD correctly positioned in the circuit would detect an unbalanced current flow and interrupt the supply. An MEN type connection is not a requirement in such situation.

6. ".....many of the modes of shock become active to neutral path."
In point of fact, it is rare that persons become in contact simultaneously with the active and neutral conductors. And there is no current method available to safeguard from such event.

7. "There is just no way arround it.....so much of what we take for granted in the electrical safety in our homes relies on an earth neutral bond and a connection to the greater mass of earth."
The "earth neutral bond" or MEN is not necessary for valid operation of an RCD. If the return current is unequal to the supply current then the RCD will trip. Any difference in these currents indicates that its return to the source is abnormal and possibly through a human body. The return current (or part of it) does not need to be via the installation but can be any alternate path to the source. The incorporation of RCD's is not reliant on the MEN system which has its own benefits and reasons for adoption that are too extensive to discuss here.

8. "NOW..these RVDs may work when the RCD is included in the inverter or generator, because there will be an earth-neutral bond in that generator or inverter."
Totally incorrect. The RVD is not reliant on a RCD or earth-neutral bond within the inverter or generator. This particular RVD does utilise connection to a RCD but only to use it as a convenient circuit breaker to be tripped by the RVD. It can just as easily have a circuit breaker incorporated within the RVD.

9. "But if it is a generaotor with no RCD built in there will be no earth neutral bond and the RCD in the caravan will not work."
If the RVD were installed in conjunction with the RCD in the caravan then the caravan wiring would be protected as intended by the RVD tripping the RCD breaker. Installed earth to neutral bonds have nothing to do with it.

The following reproduction of a diagram from the Safelec website reveals the method of installation and operation of the product. It can be seen how the tripping circuit connects to the terminals of the RVD. More information exists on their pages and can be viewed with just a little endeavour. I am disinclined to further this discussion to avoid a prolonged argument, so Bantam, you may have the final volley if you so wish.



Cheers
Allan

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Follow Up By: The Bantam - Sunday, Apr 27, 2014 at 17:10

Sunday, Apr 27, 2014 at 17:10
Please explain to me how an RCD that relies on current flowing in an earth or another alternative path back to neutral can work.....at all....when there is no earth connection....not just no earth connection to neutral....which is required but....... no earth connection period.

seriously.....describe the path from active back to neutral by an alternative means than the main neutral, that will result in a current imbalance or deficit that will result in the RCD tripping.

An RCD will not and can not work without an earth neutral bond.

Serioulsy I don't think I have missed anything...I have had this argument before and nobody has been able to describe the path by which an RCD can operate without an earth neutral bond or some alternative path back to neutral.

There has to be an alternative path back to neutral.


cheers
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FollowupID: 814349

Follow Up By: The Bantam - Sunday, Apr 27, 2014 at 17:16

Sunday, Apr 27, 2014 at 17:16
OK, I can see how the RVD may work......but the fact remains most vans are fitted with RCDs alone and people believe they work.

they simply wont with out a connection to a system that has an earth neutral bond.

That is the point of the original post.

cheers
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FollowupID: 814350

Follow Up By: Allan B (Member, SunCoast) - Sunday, Apr 27, 2014 at 18:03

Sunday, Apr 27, 2014 at 18:03
Part of the problem here is your use of the term "Earth-Neutral BOND".
The use of the word "bond" implies an intentional permanent connection between one supply line which is designated as the Neutral. This bonding connector is between the Earth bar and the Neutral bar and when in a network forms part of the MEN system. I'm sure you have no issue with that.

With a fully isolated system such as a generator or inverter, there is no reference between the live conductors and earth, so there cannot be an alternative return path to the source via earth, either metallic or soil. Again, I'm sure you appreciate that also.

The situation that can occur to change the above is if the supply source, (e.g. generator or inverter) were to suffer from an insulation breakdown between one side of its supply and the housing or frame of the machine. This could now be called a "First Fault". Effectively an earthed neutral has been formed, but it should not be termed a "bond". Correct terminology is important in engineering, particularly when safety issues are involved. Now that we have an earthed-neutral situation, any second fault such as a person coming into contact with the pseudo active conductor and some component of "earth" such as the housing of the inverter or the frame of the alternator, even possibly through the soil, will deliver an electric shock to that individual. A RCD positioned in the delivery lines from the power source will detect that there is an imbalance because the return current is travelling via an alternate path (earth) back to the source. Clearly, the RCD will trip.

Certainly there must be some form of alternate current path to produce the imbalance but it need not be by means of an intentionally earthed neutral. There can be many possible scenarios to produce an earthed line in an otherwise isolated system. Any inadvertent earthing of one line will produce the situation described, with hazardous results. It can be as simple as light rain entering the 230v output socket of an alternator and forming a conductive path to the earth pin which is connected to the frame.

The important concept to hold when considering RCD applications is that any imbalance through the RCD indicates the current is returning via an alternative path (possibly a persons body) and it matters not at all how that return is achieved, only that it is happening. The matter of MEN systems and earthed neutrals are other techniques employed to enhance electrical safety but they are independent to RCD's.

Cheers
Allan

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Follow Up By: Slow one - Monday, Apr 28, 2014 at 07:14

Monday, Apr 28, 2014 at 07:14
K&FT,

Frank, thanks for bring that devise to our attention. It will fit the bill down to a tee.

One of the good things that I can see is, it can easily be retrofitted to older vans or installations at minimal cost. You may just may have to fit a larger din rail enclosure.

Great bit of gear.
1
FollowupID: 814380

Reply By: Gone Bush (WA) - Friday, Apr 25, 2014 at 15:30

Friday, Apr 25, 2014 at 15:30
T


R


O


L


L
I'm glad I ain't too scared to be lazy
- Augustus McCrae (Lonesome Dove)

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AnswerID: 531192

Follow Up By: The Bantam - Friday, Apr 25, 2014 at 16:46

Friday, Apr 25, 2014 at 16:46
Note to other readers.

I told you there are people who don't want to hear this.

This matter has been well canvased and discussed on this and other forums in the past.

The facts, the physics, the standards and the reasons have all been produced and referenced.

There has been at least one person killed because of a failure to understand this very matter and involving a caravan and in Australia.

From my understanding the person killed was known to some members on this forum.

Make no mistake, we all need to exercise particular care when using portabe sources of 240V supply especially arround caravans and campers and especially when more than one appliance is connected to a source of supply.


You can not expect the same level of protection from electric shock you would have in most modern homes and business.

cheers
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FollowupID: 814207

Reply By: Member - Toyocrusa (NSW) - Friday, Apr 25, 2014 at 21:19

Friday, Apr 25, 2014 at 21:19
I have the Safelect unit. It came as an RCD, RVD combined unit. It is called an RCD/RVD EM. Ian from RV Powerstream, the supplier, advised this model when I supplied my specs and intended use. I have a 2500watt inverter and a 2kv generator. There is also an EMR which protects against older power sockets that can be wired active/neutral reversed. Apparently it is possible in older showgrounds but as I had not come across it I opted for the EM. Even if this is a troll it is still good to get the info out there. Cheers, Bob
AnswerID: 531222

Follow Up By: oldtrack123 - Friday, Apr 25, 2014 at 23:37

Friday, Apr 25, 2014 at 23:37
HI Keith
Good to see you do understand there is a risk level
Especially if you are using multiple class 1 [have 3pin plugs or are plugging the generator into the van power inlet socket
I suggest you contact Wayne of Safelec
& discuss your requirements with him
The Safelec RVD was original developed for exactly the reasons you are concerned about but has gone much futher now
Therere several versions dependent on application

It consist of two componentsa,a RVD which senses when the isolatopn of the generator has been lost due to a fault to earth
[THAT is when the generator becomes dangerous as far as shocks to earth are concerned ]
When that occur.It sets the RCD for actio n& if when that serious 2nd fault from what is now the active, occurs
such as a oerson it trips the RCD
So you actaully have more protection than in you home with a RCD.
But always remember there is noway to protect from shocks if you touch the active & neutral
Only for shocks to earth which are the more usual unless one deliberaty makes contact with the two active lines
Two types:
RVD-EM isbest usually fitted to the generator while if you fit one in the van the RVD-EMR is a better option
So suggest you contact WAyne 2 Safelec & discuss what will be best for you.
Will not be much use talking to most electricians as few are aware of the product yet!


ps Qlds ambulance service has just fitted RVDs to all their ambulances, thrown out the plain RCDs, So I have been told .
You will be safer than in you rown home!

PeterQ
2
FollowupID: 814249

Follow Up By: The Bantam - Saturday, Apr 26, 2014 at 23:02

Saturday, Apr 26, 2014 at 23:02
Please explain to me how an RCD works when there is no earth- neutral bond to provide a reference to the RCD and a leakage path.

If the earth wire is not connected anywhere how can any leakage current flow in it.

Serioulsy..this is a hard question and I am not trying to be funny.

If one of these devices is to work there has to be an earth neutral bond somewhere.

The standards preclude there being an earth neutral bond in the caravan wiring.
The standards also preclude there being an earth neutral bond in an inverter or generator that does not have an RCD built in.

SO, where does the earth neutral bond come from....and how do you get that to comply with standards.

The only way I can see one of these devices being of any use and compliant is if it was permanetly fitted to the generator or inverter.

cheers
0
FollowupID: 814302

Follow Up By: K&FT - Sunday, Apr 27, 2014 at 13:38

Sunday, Apr 27, 2014 at 13:38
Bantam, you are correct in that an RCD will not sense an earth leakage current where no EN bond exists.

An RVD is different and to put my interpretation on it, it is a Residual Voltage Device. In that despite there being no EN bond it will sense a leakage VOLTAGE on the earthing conductor. When it does detect this voltage it forces the RCD to trip to open the supply circuit.

It is also my understanding that it will force the RCD to trip when the leakage voltage reaches 43V which is below the permissible touch voltage(50v) in AS/NZS3000.

hope that helps mate.

frank
0
FollowupID: 814335

Follow Up By: oldtrack123 - Sunday, Apr 27, 2014 at 15:29

Sunday, Apr 27, 2014 at 15:29
HI
As Frank has pointed out:
The RVD detects when the isolated supply is no longer isolated
Ie, one line has a leakage or is connected to the earthing system system
Unlike a RCD where that connection/ leakage must occur before the RCD for the RCD to be fully functional ,the RVD detects that FAULT ANY WHERE in the system.
When/If that occur what happens depends on RVD model used.
For low currents ,up to about 5A, & using isolated supplies it can be used to directly open the circuit with that first fault[loss of isolation]

For higher currents it is used in conjuction with a RCD, such as shown in Allan"s post

In that situation:
with an isolated source if a fault to earthing system occurs anywhere in the system, it sets a true EN bond with that fault
That means the system is now an EN system
& the RCD will trip under the usual circumstances for an RCD[ line to earth fault or neutral to earth fault
l
When used with RVD operation there are two models:
[ a] RCD/RVD -EM
, for use with isolated supplies or when the poloarity of the supply can be gauranteed to be to Standards[can be damaged by incorrect polarity]
[b]RCD/RVD -EMR
where there is a chance of incorrect supply polarity
In those cases, the unit will trip immmediately.

PeterQ
2
FollowupID: 814341

Follow Up By: The Bantam - Sunday, Apr 27, 2014 at 17:21

Sunday, Apr 27, 2014 at 17:21
The point that no one has specifically pointed out is that the RVD is wired to both the supply and the load side of the RCD.

I was expecting it to be connected to the load side only.

cheers
1
FollowupID: 814351

Follow Up By: oldtrack123 - Sunday, Apr 27, 2014 at 18:45

Sunday, Apr 27, 2014 at 18:45
Hi Bantam
Was there any reason why that needed to be pointed out
Allan's post clearly showed how they are wired when used with a RCD!!
That is also available on their site.

They work equally as well with:
[1]
a floating earth system .
[2
a simple EN system
[3]
An MEN system.


PeterQ
1
FollowupID: 814356

Follow Up By: The Bantam - Sunday, Apr 27, 2014 at 21:47

Sunday, Apr 27, 2014 at 21:47
Yes there was.

remember this is a multistrand forum and prior to Alan's post this was not mentioned....AND remained unmentioned till I mentioned it.

This is critical to understanding how these things work.


This is also critical to understanding where these things can be sited.

An RVD can not be installed alone and remote from the RCD..and they will not work with ANY or an existing RCD.

They work with an RCD they are installed alongside..they must have access to both the supply and load side of the RCD.

Why you would even bother marketing these deviced as a stand alone item I do not know.....they must be installed as part of or right beside an RCD and they can not work without one.


now...another matter.

Just like an RCD, they will not protect aginst an active to neutral shock.
a fact that most normal people do not grasp.


they will restore some of the safety that most take for granted iwhen used in portable supplies, but there are a range of hazxards that still remain unprotected.


People still need to take particular care with electricity afrom portable sources of supply and arround caravans.

cheers
0
FollowupID: 814370

Reply By: Member - KeithB - Friday, Apr 25, 2014 at 23:44

Friday, Apr 25, 2014 at 23:44
Great advice and incredibly informative. Many thanks to all who have made the effort to reply.
Keith
AnswerID: 531235

Reply By: oldtrack123 - Saturday, Apr 26, 2014 at 00:08

Saturday, Apr 26, 2014 at 00:08
Hi Keith
In direct anwser to your question
If that is an " inverter" wired into the van wiring it SHALL be done in accordance with the Standards AS /NZS 3001
THat means using a multipole change over switch when changing from mains to inverter
Wnen correcty wired in the exiting RCD will work correctly.
But as others have said ,do not use an earth stake anywhere
Do not deliberately connect the van to mother earth by any means such as an earth stake, connecion to a steel structure ,water pipe etc
The Standards state that "an earth stake is neither required or recommmended"!
!In fact they can, in that situation, lead to problems!


note:
the above applies to Inverters &/ Or generators only

Inverter /chargers may require a different approach depending on actual model
They need even more care in being correctly wired in!!!


PeterQ
AnswerID: 531236

Follow Up By: The Bantam - Sunday, Apr 27, 2014 at 17:27

Sunday, Apr 27, 2014 at 17:27
Sorry to harp on the point...but is the caravan has no earth neutral bond, and the inverter or generator has no earth neutral bond AND no earth neutral bond has been introduced......the RCD ( not RVD) will not trip.

A large number of poeple use both inverters and generators with their caravans by pluging them into the caravan inlet socket on the side of the van.

both the caravan and the inverter/generator comply.

There is no changeover switch and there is no introduced earth neutral bond and the RCD will not work.

The sooner that all 240v mains appart from a single battery charger is iliminated from caravans the better as far as I am concerned.

we are close to that being a real posibility.

cheers
0
FollowupID: 814352

Reply By: oldtrack123 - Sunday, Apr 27, 2014 at 19:04

Sunday, Apr 27, 2014 at 19:04
HI Bantam
You just do not undestand the principles
THEY DO WORK
I have both the very early model & the lates RVD-EM
They do work tested, proven by myself

Tested & approved by the authorities.

Approval #NSW25662
Many have been sold
Qld Ambulance have installed them on all their ambulance as they are considered a safer option than a 10mA RCD.[yes ,they have inverters on board]
The initial protection of an isolated supply is maintaned
One big difference between them & a RCD on its own
is that for the RCD to trip it must have an EN bond upstream from it
THe RVD will detect any fault that creates a EN, ANYWHERE, in the system & can trip the RCD
IT reads voltage between Actives[of an isolated supply] & the earthing system
When it sees that voltage between EITHER lines[ACTIVEs] to earth it treats that as an EN system
The RVD does not rely on out of balance currents!.




Read my description SLOWLY!

PeterQ
AnswerID: 531356

Reply By: oldtrack123 - Sunday, Apr 27, 2014 at 19:54

Sunday, Apr 27, 2014 at 19:54
{Quotee" The Bantam posted:
Sorry to harp on the point...but is the caravan has no earth neutral bond, and the inverter or generator has no earth neutral bond AND no earth neutral bond has been introduced.
....[1].the RCD ( not RVD) will not trip.

A[2] large number of poeple use both inverters and generators with their caravans by pluging them into the caravan inlet socket on the side of the van.

both the caravan and the inverter/generator comply.

There is no changeover switch and there is no introduced earth neutral bond and the RCD will not work.

The sooner that all 240v mains appart from a single battery charger is iliminated from caravans the better as far as I am concerned.

we are close to that being a real posibility.

cheers


HI
Yes, a RCD on its own does, require an out of balance current flow through it for it to trip and on it's own that requires a EN bond upstream from the RCD for it to trip

Plugging isolatedinverters or generators into the van inlet socket leaves the van RCD inactive
THat can be dangerous if that isolation of the inverter or generator is lost ANYWHERE in the system .& multiple class 1 devices are used

THat was one of the original basis for a RVD to detect when /if that isolation was lost ANYWHERE in the system.

OF course if the inverter or generato ris permanently wired into the sustem a change over switch shall be used,in order to create an EN bond in the van & isolate the entire system from the van inlet socket

ANY system which uses inverters[ voltages exceeding 50V AC] should have shock to earth protection,even though no mains connection is available!!
!
So Inverters ofF good batteries or other low voltage DC sources will ideallly be fitted with a RCD/RVD -EM [NO neutral , installed as an isolated supply as first line of protection]

PeterQ
PeterQ
AnswerID: 531364

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