240 V safety

Submitted: Tuesday, Jun 21, 2011 at 19:38
ThreadID: 87117 Views:2864 Replies:3 FollowUps:22
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Hello,
I have a brand new van with RCD installed.
If I run the generator (if camping situations permit) to power the van, am I assuming the power points are protected by the van's RCD.
Furthermore, if , on rare occasions, I needed 240V power thru the 2500W pure sine inverter and ran a lead from inverter (in front boot) to the van power inlet, would the power points be protected by the van's RCD?
I have read about the dangers of running 240V power direct from inverters (which have no inbuilt RCD) to appliances via power leads.
Many thanks,
Ian
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Reply By: dbish - Tuesday, Jun 21, 2011 at 19:48

Tuesday, Jun 21, 2011 at 19:48
If you use a generator or inverter the vans RCD will not work as both sources are Isolated types of powersupplys. Also earthing the generator wont help either as the earth conection on the generator is only conected to the shell.
AnswerID: 458110

Follow Up By: new boy - Tuesday, Jun 21, 2011 at 19:59

Tuesday, Jun 21, 2011 at 19:59
Why if the genset is pluged into the normal 240 inlet (which is what I do) wont the RCD work would have thought 240 power whether genset or caravan park is the same.
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FollowupID: 731454

Follow Up By: oldtrack123 - Tuesday, Jun 21, 2011 at 21:22

Tuesday, Jun 21, 2011 at 21:22
Hi
The van RCD is definitely not operational with a standard portable generator or inverter plugged into the van power inlet socket
If you believe so ,because the RCD trips when you press the test button you are wrong
The test button only tests the RCD's mechanism .
IT does not check that everything is wired for correct operation

The mains , generator & inverter voltages are similar[240v ]

But the wiring /supply system is very different


You should use great care if using your generator / inverter plugged in via the van power inlet.
It is a general safety recommendation to only connect ONE class 1devise[ which requires a 3pin plug ]into a portable generator or inverter AT any time
Your van itself become that ONE class one devise .
EACH additional class 1 devise plugged into the van wiring increases the risk of possible shock in the event of possible faults in wiring or equipment.

The risk is low but the potential is there.

The other options are
[a] have your generator/ INVERTER PERMANENTLY FITTED WITH It's OWN RCD
[b]Have the generator /inverter permanently fixed & wired via suitable switching in the van or
You may use multiple class 2 devices [2pin plugs] with a very low risk..

MANY claim there is no risk. but people have died using portable generators & inverters

It's your decision . the requirements are not mandatory YET for private use

BUT all such generators & inverters MUST now be fitted with a permanent rCD
when used in the building , construction industry. etc

NOTE portable power boards etc fitted with RCD & other forms of plug in RCD's also do not function

,Peter
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FollowupID: 731471

Follow Up By: oldtrack123 - Tuesday, Jun 21, 2011 at 21:40

Tuesday, Jun 21, 2011 at 21:40
HI Ian
If you can post make & model number of inverter would help.

A word of caution.
Many manuals are not written for Aus requirements & in fact some information is totally incorrect & dangerous.

Peter
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FollowupID: 731477

Follow Up By: oldtrack123 - Tuesday, Jun 21, 2011 at 21:49

Tuesday, Jun 21, 2011 at 21:49
Hi Ian
One other point which may be contrary to the manuals
Do not use an earth stake: "It is not required or recommended "under AUS rules!
This includes deliberately earthing in any form except by the power supply lead earth connection

Peter
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FollowupID: 731481

Follow Up By: Member - iijmartin - Wednesday, Jun 22, 2011 at 07:25

Wednesday, Jun 22, 2011 at 07:25
Thanks Peter for the info. I will look into the URCD.
Regards,
Ian
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FollowupID: 731511

Reply By: Robin Miller - Tuesday, Jun 21, 2011 at 21:03

Tuesday, Jun 21, 2011 at 21:03
Inverters of that power level are not your normal cheapies Ian and I think we would need to know more about it before a definative answer could be given- does handbook refer to your case or describe its earthing status / System.
Robin Miller

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AnswerID: 458119

Follow Up By: oldtrack123 - Tuesday, Jun 21, 2011 at 21:35

Tuesday, Jun 21, 2011 at 21:35
Hi Bob
Unfortunately that product is on hold at the moment due to commercial matters.
But a sister product "URCD" is available which replaces your van RCD & you then have protection when any source is plugged into the van power inlet
Contact
"info@powerstream.com.au"

No financial or personal interest in the company but have followed the development of the product & INMHO the absolute best available solution for safety with portable generators & inverters
Peter
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Follow Up By: Member - iijmartin - Wednesday, Jun 22, 2011 at 07:22

Wednesday, Jun 22, 2011 at 07:22
Robin,
The inverter was sold as a pure sine 2500 w with Aust compliance stickers, not expensive. Says pure sine but I don't think I will ever trust it on computers etc. Needed this size to power partner's important piece of equipment - 240v hair dryer. I will have to put a timer on the vanity bench!
Cheers,
Ian
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FollowupID: 731510

Follow Up By: Robin Miller - Wednesday, Jun 22, 2011 at 07:42

Wednesday, Jun 22, 2011 at 07:42
Ian a good test anyone can do with inverter like that is to brieflly plug in a fan heater or microwave - if the appliance makes a different (generally rougher/louder) noise then the waveform is not sine.

In the world of electrical saftey their are different trains of thought and for each you can have arguements for and against. I prefer the double insulated path. Most likey your very important application , the hair dryer is such , and you should be ok.

Either way always insist that the user of the hair dryer has appropriate footwear on and get really mad if you see such a person with bare feet in a bathroom holding the dryer.



Robin Miller

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Follow Up By: Member - iijmartin - Thursday, Jun 23, 2011 at 07:18

Thursday, Jun 23, 2011 at 07:18
Thanks Robin, I will test the inverter with the fan heater.
The hair dryer!! For me it's not a problem..lost most of my hair yrs ago. Kath, on the other hand, has thick, frizzy and beautiful hair. Hence you can see my dilemma.
All the best,
Ian
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Reply By: Battery Value Pty Ltd - Tuesday, Jun 21, 2011 at 22:43

Tuesday, Jun 21, 2011 at 22:43
Hello Ian,

an RCD isn't needed if neither of the 2 wires from the 240V power source is connected to an earth wire (this is called a 'floating' supply).

As long as the wires are kept isolated from the earth (this includes structures you touch with your hand or feet), you could touch either one of them without getting zapped. But of course if you touched both of them at the same time, it's a different story.

Now consider a faulty wire insulation causing a connection between a wire and earth/caravan body/chassis etc. This wire then becomes the 'neutral' wire, while the other one becomes the 'active', or hot wire.
If you touch neutral, nothing happens, but if you touch the hot one, you could get zapped.

How would an RCD protect you in this situation?
You have to keep in mind, that the RCD senses the difference between the two currents in the two wires.
If everything's working as it should, there's no difference, but if one wire suddenly carries less current than the other one, then the RCD trips (opens the circuit).

So how could you make the RCD trip, i.e. how can one wire suddenly carry a smaller current when you touch the active/hot wire?
For this, you have to introduce a third current path, called the earth wire, and provide a connection at the power source between earth and one of the two main conductors, which now becomes 'neutral'. You'd also have to connect the earth wire to the caravan/towing vehicle chassis and gennie chassis, for full protection.

In case you touch the active/hot wire, a small current could start to flow through your body to the earth/caravan body/chassis and back to the power source via the earth wire.
It is this small current which is suddenly missing in the neutral wire going through the RCD, and it trips.

Note that an earthed system without RCD is more dangerous, than a non earthed (floating) system without an RCD.
The best protection is offered by an earthed system with RCD, because the RCD detects any insulation breakdown between active/hot and associated leakage current from this wire to earth. So there's no chance that something can become 'life'.
But if the RCD goes faulty, you end up with a dangerous earthed system without RCD, thus the importance of periodical tests carried out on the RCD.

In a nutshell, if the RCD is already installed inside your van, I'd connect the generator chassis, van and towing vehicle with an earth wire (common negative, or chassis ground is suitable). This earth wire needs to be connected to the 240V power outlet socket on the gennie, and to the neutral on the same socket, via the extension cord between gennie and van.
Ask an electrician who can tell you which one it is.
For the ultimate protection, also use a plugin type RCD at the gennie 240V socket.

Legal disclaimer:
All the above is given on 'technical information only' basis.
Due to the legalities covering all matters 240V, I can't be made responsible for any actions resulting in damage or personal injury/death.

cheers, Peter




AnswerID: 458130

Follow Up By: Member - iijmartin - Wednesday, Jun 22, 2011 at 07:33

Wednesday, Jun 22, 2011 at 07:33
Hello Peter,
As you can tell by my original post my knowledge of electrical circuits is very limited. However, I have always had a healthy respect for all 240v setups. It is great to get all this info on forums..so myself and others can make their own risk assessments.
Cheers,
Ian
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FollowupID: 731512

Follow Up By: Dennis Ellery - Wednesday, Jun 22, 2011 at 10:35

Wednesday, Jun 22, 2011 at 10:35
Peter,
What you are saying is illegal - dangerous stuff advising unlicensed people to jerry rig a genset to trip out on an RCD.
People would do well to follow oldtracks advice, as he is an expert on the subject and the legal requirments that go with it.
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FollowupID: 731527

Follow Up By: oldtrack123 - Wednesday, Jun 22, 2011 at 10:45

Wednesday, Jun 22, 2011 at 10:45
Hi Peter of BW
Re:"quote"Note that an earthed system without RCD is more dangerous, than a non earthed (floating) system without an RCD.
The best protection is offered by an earthed system with RCD, because the RCD detects any insulation breakdown between active/hot and associated leakage current from this wire to earth. So there's no chance that something can become 'life'.
But if the RCD goes faulty, you end up with a dangerous earthed system without RCD, thus the importance of periodical tests carried out on the RCD[end quote]

Exactly the reason I post that floating systems are not as safe as some believe or make out
An insulation fault can exist & lie dormant, without ANYONE knowing they now have an earthed neutral system .
The fault can be anywhere in the system INCLUDING equipment & THAT is the main reason for only having ONE CLASS 1 DEVISE CONNECTED
THAT has been the long accepted safety practise for many many years.
It does not matter how good the soource's insulation is, the earth fault can /does / has occuured elsewhere.
This is something that many do not seem to understand.
This is the reason that it is now mandatoryfor buiders , constuction ,tc to have PERMANENTLY fitted RCDs to ALL generators

Accidents , including deaths did occur with the supposidly safe fully isolated sources .

BUT I cannot agree with this
[quote]"
In a nutshell, if the RCD is already installed inside your van, I'd connect the generator chassis, van and towing vehicle with an earth wire (common negative, or chassis ground is suitable). This earth wire needs to be connected to the 240V power outlet socket on the gennie, and to the neutral on the same socket, via the extension cord between gennie and van.
Ask an electrician who can tell you which one it is.
For the ultimate protection, also use a plugin type RCD at the gennie 240V socket[end quote]

The standards demand that if the portable generator has an earthed neutral then an RCD Should be PERMANENTLY FITTED & WIRED to the generator.
A plug in RCD is not acceptable.
Under no circumstances should ANY ONE other than a qualified electrician attempt such modification.
Doing so is illegal & leaves the person open to expensive & serious charges
A further reason is that some inverter gennys require a specific RCD for correct operation
The common earth wire should only be the the one in the connecting cable,[extension lead ]no other is required or needed
& should ONLY BE CONNECTED TO THE EARTH PINS!!

Peter
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FollowupID: 731528

Follow Up By: oldtrack123 - Wednesday, Jun 22, 2011 at 11:03

Wednesday, Jun 22, 2011 at 11:03
Hi Ian
Just a clarification. many of the posts just refer to generators , anything that applies to generators in this context also includes inverters.

Peter
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FollowupID: 731530

Follow Up By: Battery Value Pty Ltd - Wednesday, Jun 22, 2011 at 11:08

Wednesday, Jun 22, 2011 at 11:08
@ Dennis,

spreading technical information isn't illegal.
Read the disclaimer.

@Peter,

agreed.
So if the gennie manufacturer provides a connection between 240V socket earth, and gennie chassis, he's obliged to fit an RCD to the gennie.

I'd assume so, otherwise you'd have an earthed system with no RCD - dangerous.

But plugging in an additional RCD device provides an additional layer of safety because if the inbuilt one fails, the plug in one still can protect.
The plug in type RCD does in no way make the system unsafe.
But it makes it potentially safer.

cheers, Peter

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FollowupID: 731533

Follow Up By: oldtrack123 - Wednesday, Jun 22, 2011 at 12:12

Wednesday, Jun 22, 2011 at 12:12
Hi Peter

RE :"But plugging in an additional RCD device provides an additional layer of safety because if the inbuilt one fails, the plug in one still can protect.
The plug in type RCD does in no way make the system unsafe.
But it makes it potentially safer ""


No argument there.
My point was that a plug in RCD is inoperatable with an isolated supply which as you & I both know ,is correct
Although some may be mislead by the articles on generator & inverter safety on this forum
Peter
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FollowupID: 731535

Follow Up By: Dennis Ellery - Wednesday, Jun 22, 2011 at 12:36

Wednesday, Jun 22, 2011 at 12:36
Peter
I will rephrase that - what you are advising people to do is illegal - dangerous stuff - unlicensed people wiring a 240V genset to trip out on an RCD.
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FollowupID: 731536

Follow Up By: Member Al (Sunshine Coast) - Wednesday, Jun 22, 2011 at 13:37

Wednesday, Jun 22, 2011 at 13:37
To 'Peter of Battery Value' and to 'Oldtrack123 Peter',

What Dennis Ellery has said re giving advice on electrical matters that are subject to Regulations has some merit.

Appending a 'Disclaimer' to your expression does not necessarily absolve you from legal responsibility. This is especially so if you are a licensed electrical worker or an electrical professional person. There are legally enforceable rules imposed on these people.

Each of you make expressions which could easily be misunderstood or misinterpreted by the reader and lead to inappropriate action or behaviour. I decline to define here those expressions to which I refer otherwise we will enter into another interminable argument. I will simply repeat my previous recommendation that such subjects should not be discussed on an open forum and the inquirer should be directed to seek specific advice from a licensed electrician.

Cheers
Allan

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FollowupID: 731544

Follow Up By: oldtrack123 - Wednesday, Jun 22, 2011 at 13:58

Wednesday, Jun 22, 2011 at 13:58
Hi Al
Now, you do have me confused
I have reread my posts & see nothing that would encourage anyone ,other than a licensed elecrician ,to carry out such modifications
I do not post explicit details for that very reason.
I do believe I am correct in posting why such should not be done & that RCDs will not work in certain situations'
I see nothing particular wrong in Peter of BW explaining how ,why a shock can occur with the SUPPOSEDLY SAFE ISOLATED SUPPLY

I do not /did not agree with the additional details on how to overcome the problem!!

Perhaps you have misread the "quotes" in my posts as being mine???


Peter
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FollowupID: 731547

Follow Up By: oldtrack123 - Wednesday, Jun 22, 2011 at 14:24

Wednesday, Jun 22, 2011 at 14:24
Hi Allan

Re :"{quote} the inquirer should be directed to seek specific advice from a licensed electrician. end quote

Always provided THAT licensed electrician knows about the requirements of the appropriate standards
Many are not even aware they exist
Have seen THAT many times
An incident quite recently
A Brisbane electrical test & tag company were recently modifying Clipsal orange power boards to work as a plug in RCD for a Brisbane Honda generator dealer
Who when questioned. guaranteed they complied with the Standards because they had been tagged & tested
A quick email by me to the Electrical safety office got a quick response.
The dealer had to recall & refund all those that had been sold

I would suggest that anyone who has been sold such a devise return it immediately for refund
They do not have approval , they do not comply with the standards.

But so much for seeing your licensed electrician, when a test & tag co were not aware of the regs & their obligations

Peter
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FollowupID: 731551

Follow Up By: Dennis Ellery - Wednesday, Jun 22, 2011 at 14:58

Wednesday, Jun 22, 2011 at 14:58
Hi Oldtrack and Battery Value.
My comments were directed at the Peter of Battery Value.
My apoligies, as I should have been more specific
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FollowupID: 731562

Follow Up By: oldtrack123 - Wednesday, Jun 22, 2011 at 15:57

Wednesday, Jun 22, 2011 at 15:57
Hi Dennis
No problem ,
I understood, as I believe did Peter of BV.


Peter { not the BV one]
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FollowupID: 731568

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