240v switching mains to inverter

Peter and Jian · Member

240v switching mains to inverter

Peter_n_Margaret · Guru

Yes you can.
You need to consult a licensed electrician who is familiar with AS3001, "Transportable buildings".
A 3 way battery switch is NOT suitable.
Anyone who tries to tell you how to do it on a public forum could leave themselves open to very serious charges if/when it goes wrong.

Cheers,
Peter

Peter and Jian · Member

Thanks for that....good advice

Peter_n_Margaret · Guru

When you connect to the inverter, the RCD in the van becomes non operational (even though it will seem to test OK), so I would strongly suggest that you also change it for an RVD in order to maintain maximum safety levels.

Cheers,
Peter

Peter and Jian · Member

All too difficult,....I have read that the inverter is a floating 240v system and should not be earthed. therefore....no problem ill just run a power point from the appliance i want to run back to the inverter..

all good

thanks

Peter

Peter_n_Margaret · Guru

Peter and Jian wrote:
All too difficult,....I have read that the inverter is a floating 240v system and should not be earthed. therefore....no problem ill just run a power point from the appliance i want to run back to the inverter..
all good

thanks

Peter

It is not so hard.

It is quite safe to run a single appliance from the inverter, but not more than one at a time (unless they are double insulated). Exactly the same applies to a generator.

Yes, they are "floating" power supplies.

Cheers,

Peter

Mike Harding · Guru

Peter_n_Margaret wrote:
It is quite safe to run a single appliance from the inverter, but not more than one at a time (unless they are double insulated).

Why do you say that Peter?

Peter and Jian · Member

mike. I think Peter would be referring to perhaps power tools used outside the van perhaps.....

none the less however, I have received some valuable advice,

thanks to all

Peter_n_Margaret · Guru

Mike Harding wrote:
Peter_n_Margaret wrote:
It is quite safe to run a single appliance from the inverter, but not more than one at a time (unless they are double insulated).
Why do you say that Peter?

Because with an isolated power supply, the RCD will be ineffective which means that if there is a fault with 2 separate appliances and you happen to touch both then you could be electrocuted and the RCD will not protect you. An RVD operates differently and provides that protection. This risk does not occur if the appliances are double insulated.

Cheers,

Peter

El Gringo · Senior Member

This might give you an idea of what it should look like.
Mine switches between 3 sources mains, generator or inverter.
Done professionally by a tradesman who knew the regs.

Cheers,

oldtrack123 · Guru

Peter_n_Margaret wrote:
Yes you can.
You need to consult a licensed electrician who is familiar with AS3001, "Transportable buildings".
A 3 way battery switch is NOT suitable.
Anyone who tries to tell you how to do it on a public forum could leave themselves open to very serious charges if/when it goes wrong.

Cheers,
Peter

DITTO smile biggrin

oldtrack123 · Guru

Peter and Jian wrote:
Hi there, is there such a switch/terminal that can be used to switch 240v input between mains and the inverter.
I thought of a battery 3 way switch, but no one is game enough to say "yes you can" ...any ideas?

Peter

A battery 3way switch should NEVER be used on 240V !!!

Peter and Jian · Member

Thanks very much... nice to know it is possible and my thought process was on track.

peter

oldtrack123 · Guru

Peter_n_Margaret wrote:
Mike Harding wrote:
Peter_n_Margaret wrote:
It is quite safe to run a single appliance from the inverter, but not more than one at a time (unless they are double insulated).
Why do you say that Peter?
Because with an isolated power supply, the RCD will be ineffective which means that if there is a fault with 2 separate appliances and you happen to touch both then you could be electrocuted and the RCD will not protect you. An RVD operates differently and provides that protection. This risk does not occur if the appliances are double insulated.
Cheers,
Peter

Yes!!

Fully agree !

The safety recommendation is:

NEVER connect more than ONE class 1 device to an" electrically isolated power supply" [inverter or generator]

Multiple class 2 ,with one class 1 can be safely used ,with very low risk of shocks to earth

class 1 shall have a 3 pin plug Class 2 only require a 2 pin plugs

T1 Terry · Guru

Something to keep in mind, the caravan or motor home has a connection to the conductive material to the green and yellow earth cable and that makes it part of the earth circuit and therefore considered a class 1 appliance because the conductive area is connected to the earth cable.
Now the bit that needs to be explained by those that like to stipulate the inverter body must be connected to the chassis of the vehicle, if the inverter body is connected to the vehicle body conductive areas via a common link to the earth cable, is any class one appliance now safe to be plugged into the inverter? After all, the now common earth link between the inverter and the conductive area of the vehicle makes the vehicle the first class 1 appliance connected to the inverter, any thing else plugged in to the inverter would now be the second appliance.

T1 Terry

Mike Harding · Guru

Peter_n_Margaret wrote:
Mike Harding wrote:
Peter_n_Margaret wrote:
It is quite safe to run a single appliance from the inverter, but not more than one at a time (unless they are double insulated).
Why do you say that Peter?
Because with an isolated power supply, the RCD will be ineffective which means that if there is a fault with 2 separate appliances and you happen to touch both then you could be electrocuted and the RCD will not protect you. An RVD operates differently and provides that protection. This risk does not occur if the appliances are double insulated.

A bit of a long bow I think.

This would require appliance number one to develop a fault which causes its chassis to become connected to active without tripping an overcurrent breaker and remain in that state indefinitely and, at some future point, appliance number two to develop a fault which caused its neutral to become connected to chassis without tripping a breaker and for both faulty appliances to be connected at the same time and then for a user to simultaneously touch both appliances....?

It is theoretically possible but I suggest one has a greater chance of being struck by lightning while in an underground mine, standing in a bowl of custard, and singing Advance Australia Fair to the tune of Three Blind Mince.

T1 Terry · Guru

Mike, consider this, all houses and systems that have an operative RCD have one leg of an otherwise floating system tied to the earth wire and therefore the conductive parts are already in what you call a fault condition. By linking one leg of the 240v to earth a floating system becomes an active/neutral system. This doesn't trip an over current breaker and no one feels an electric shock because only one leg of the AC is exposed. This connection is made before the RCD so it can sense another connection of the neutral to the earth after the RCD and trip the breaker.
In a floating system neither leg is tied to the earth wire, so there is just line 1 and line 2. Say a fault occurs inside the walls of the RV and either line 1 or line 2 come into contact with part of the conductive body work. No one will feel it and nothing in an RCD will sense it. Now all that is required is a fault in an appliance that makes the conductive area live to the other leg of the floating system. Same deal, no one would feel anything because again, it is only one leg and the RCD won't sense it. Now the person holding the faulty appliance touches the body. The body is connected to say line 1, the appliance body to line 2. The RCD still doesn't sense a fault and as long as the current passing through person now in contact with both line 1 and line 2 doesn't exceed the 16 amps limit of the over current circuit breaker, the RCD will just sense the person is another appliance with possibly fatal consequences.
Many of the better quality *UPS style inverters now have an auto switching earth/neutral link and built in RCD so the 240vac is always protected by an RCD.

T1 Terry

* uninterrupted power supply, switches to mains when available and back to inverter when mains power is lost

-- Edited by T1 Terry on Friday 20th of April 2018 08:45:48 AM

Bagmaker · Senior Member

you also need to isolate the external input plug point from 240v AC inverter feed.
wouldnt want little johnny fiddling with that whilst the rig is battery powered

oldtrack123 · Guru

Bagmaker wrote:
you also need to isolate the external input plug point from 240v AC inverter feed.
wouldnt want little johnny fiddling with that whilst the rig is battery powered

That is covered IF the inverter is being used correctly, OR is correctly PERMANENTLY wired in. accordance with the standards & as covered by the Electrical regulations of EVERY state carried out by a licensed person familiar with the appropriate Standard

That is why the inverter or generator should only be used in accordance with the AUs Standards & Safety recommendations

All should understand that even the smallest 240V inverter can KILL

oldtrack123 · Guru

Peter_n_Margaret wrote:
Mike Harding wrote:
Peter_n_Margaret wrote:
It is quite safe to run a single appliance from the inverter, but not more than one at a time (unless they are double insulated).
Why do you say that Peter?
Because with an isolated power supply, the RCD will be ineffective which means that if there is a fault with 2 separate appliances and you happen to touch both then you could be electrocuted and the RCD will not protect you. An RVD operates differently and provides that protection. This risk does not occur if the appliances are double insulated.
Cheers,
Peter

Peter is TOTALLY correct

The potential risks of electrocution when connecting more than ONE class 1 device, to an electrically isolated source has long been recognized

The safety recommendation for many many years has been & still is:

DO NOT CONNECT MORE THAN ONE Class1 device @ any time.

One class 1 &/or multiple class 2 [ double insulated to Standards ]approved can be connected with a high degree of safety from shocks to "earth"

Shocks & electrocution actually occurred before this recommendation came in.

It was introducd many years ago

-- Edited by oldtrack123 on Friday 20th of April 2018 10:42:10 AM

oldtrack123 · Guru

T1 Terry wrote:
Something to keep in mind, the caravan or motor home has a connection to the conductive material to the green and yellow earth cable and that makes it part of the earth circuit and therefore considered a class 1 appliance because the conductive area is connected to the earth cable.
Now the bit that needs to be explained by those that like to stipulate the inverter body must be connected to the chassis of the vehicle, if the inverter body is connected to the vehicle body conductive areas via a common link to the earth cable, is any class one appliance now safe to be plugged into the inverter? After all, the now common earth link between the inverter and the conductive area of the vehicle makes the vehicle the first class 1 appliance connected to the inverter, any thing else plugged in to the inverter would now be the second appliance.

T1 Terry

I do not quite understand what you are saying

An approved FULLY isolated source [inverter or generator] has to meet very strict insulation "Standards "requireiments regarding both insulation quality /longevity etc between the high voltage & lower voltage sides & the higher voltage to "earth/frame"

Who stipulates that the portable inverter or generator body must be "earthed"??

The fact is that the regulations clearly say that such should not be deliberately '"earthed "to the general mass of earth

But there is a very obvious need for the metal frame of a generator or If the inverter has such ,for a good electrical bond between earthed conductive surfaces of the van back to the generator frame' as anyone who fully understands the risks would see

Correct "earthing" is a lot more complicated than many think.

More "Earths " is not always better

Incorrect earthing can have nasty outcomes

It can even increase the risks of shocks & fires

-- Edited by oldtrack123 on Friday 20th of April 2018 11:30:14 AM

T1 Terry · Guru

I'll try to draw the path. If the inverter body is connected to the vehicle chassis and so is the 240vac system earth wire connected to the chassis, effectively the inverter body is connected to the AC earth circuit. As far as the inverter or generator meeting very high insulation standards, I'm guessing any 240vac appliance must meet the same standards. If we are considering the possibility of an appliance having a fault to the conductive body then how can we ignore the possibility of the generator or inverter suffering the same problem?

T1 Terry

Mike Harding · Guru

Sorry, can't reply at present... too busy looking for a bowl of custard and the musical score for Three Blind Mice.

Honestly! You people need to get out more....

Peter_n_Margaret · Guru

It was YOU who asked the question. Clearly you know it all already if you are not interested in the answer?
And clearly the rest of us are not as smart as you........ so we might learn something from some of those others (and that was not a question).

Cheers,
Peter

oldtrack123 · Guru

T1 Terry wrote:
I'll try to draw the path. If the inverter body is connected to the vehicle chassis and so is the 240vac system earth wire connected to the chassis, effectively the inverter body is connected to the AC earth circuit. As far as the inverter or generator meeting very high insulation standards, I'm guessing any 240vac appliance must meet the same standards. If we are considering the possibility of an appliance having a fault to the conductive body then how can we ignore the possibility of the generator or inverter suffering the same problem?

T1 Terry

Hi Terry

You should get ALL the appropriate standards rather than make assumptions on a public forum biggrin

Totally different Standards apply to Fully isolated supply sources ,compared to non isolated supply sources

Just as totally different Standards apply to double insulated devices compared to single insulated devices ,ie those which require an earth connection

Are you again suggesting that you are wiser than all those highly qualified people who have input into the electrical Standards

Of course we can all dream up extreme situations where problems could occur .

NOTHING is FOOL proof!!

The safest way is to not have portable [plug & socket connected] generators or inverters or appliances, but to have them permanently wired in in accordance with the Standards.

But that is not always practical.

The next step will be for manufacturers to have to fit permanent earth leakage detection into the isolated supplies[ along the lines of a RVD] so that the source shuts down even for loss of isolation within the source

I may not see that cry as a Standards requirement, but it will not be long

In fact some small portable generators makers have already gone that far.

Ahead of the pack & the Standards

Something along the original concept of Ian's RVD [when he first raised the idea & was seeking comments, from such as myself], [not switching the load,but deactivating the control system]

Relatively easy with inverter generators & inverters biggrin

-- Edited by oldtrack123 on Friday 20th of April 2018 10:38:47 PM

-- Edited by oldtrack123 on Friday 20th of April 2018 10:40:52 PM

Aus-Kiwi · Guru

Thing is thereâs 3 phases or alternating supply . Not the same as 12v or DC where there is no wave form . So two AC power sources CANNOT be joined ., Even us lineworker shave issues with different power sources ! In a caravan it can be catastrophic! Burning to ground in no time . Itâs not a matter of knowing what your doing ! It just cannot be done with out altra safe switching auto switching which takes the human fail out of it making it fail save .

T1 Terry · Guru

Sorry Peter, from now on I'll add a note to all appliances and inverters that I fit that it is against the standards to have a fault to the conductive part of the body and they should not even consider doing such a thing. Not sure how I should word it, maybe "Thou shall not fault to and conductive surface lest though suffer the wrath of Peter Oldtrack123 and the fury of the standards police" would that cover it?
But then that would negate you rule of only one class 1 appliance in a floating supply because all appliances would no better that to have a fault to earth :roll:

T1 Terry

oldtrack123 · Guru

T1 Terry wrote:
Sorry Peter, from now on I'll add a note to all appliances and inverters that I fit that it is against the standards to have a fault to the conductive part of the body and they should not even consider doing such a thing. Not sure how I should word it, maybe "Thou shall not fault to and conductive surface lest though suffer the wrath of Peter Oldtrack123 and the fury of the standards police" would that cover it?
But then that would negate you rule of only one class 1 appliance in a floating supply because all appliances would no better that to have a fault to earth :roll:

T1 Terry

Well I read & reread above & it still make no sense!!

You would obviously have great difficulty in understanding the whole 700 odd pages of As/NZS 3000

The Standards &rules make very good sense IF you can retain more than one line @ a time.

"Fitting appliances & inverters ""?

Are YOU doing Licensed Electrical Work ?????.

Regarding Standards ,from a post on another forum

"A bit off topic , but last night I had a run through on an Australian electrical forum that I am a member of.

As usual ,I was astounded by some of the questions & comments made by some licensed "Electricians ?
Mainly in regard to the new Standards which give considerably more leeway on subjects like circuit loading ie more onus on the electrician to understand the intent of the rules
That means using their brains & teck knowledge :roll:
I am afraid at the obvious LACK of some basic knowledge & understanding exhibited from some "electricians" :shock:

Terry posted

"I'll try to draw the path.

[a]If the inverter body is connected to the vehicle chassis and so is the 240vac system earth wire connected to the chassis, effectively the inverter body is connected to the AC earth circuit.

As far as the inverter or generator meeting very high insulation standards, I'm guessing any 240vac appliance must meet the same standards. If we are considering the possibility of an appliance having a fault to the conductive body then how can we ignore the possibility of the generator or inverter suffering the same problem?"

I will have another go

[a] If it is an approved fully isolated the inverter, the Standards require an extremely high level of electrical . isolation of the 240V part from the inverter body. AND all the 12V

It does not matter that the inverter body or generator frame is in contact or connected to with the vehicle earthing system .

In fact it is a Shall requirement,& occurs via the Earth cable in the connecting lead. AND THAT is the only "earth" connection required. No connection to mother earth [ NO earth stake]

No connection to electrically earthed structures

It is not just a SHALL requirement, but a basic requirement for safety purposes & full correct operation of the RCD [ if fitted to the generator ]under virtually all foreseeable circumstances

Perhaps a little clue for you to consider "Shunt earth leakage currents"

Perhaps you are thinking about the inverters which have been banned for YEARS in Aus ,that were not fully isolated & led to many accidents including deaths???

[B]No ,There are substantially different requirements ,substantially different STANDARDS for fully isolated sources such as portable generators & inverter. as compared to generall electrical appliances etc

Perhaps you do not really know the full extent of ALL the Electrical Standards.?????

There are different Standard for:

large portable fixed wired generators[ emergency supply units]

for large inverters permanently wired in

for ups

for inverter chargers

Of course depending on what your risk assessment is we could call for triple or quad or even higher levels of isolation. but @ this stage it seems there is no valid reason to go that far

For Instants there are even further requirements covered by specific Standards for ALL electrical equipment used in patient areas Wards etc in hospitals

How far do you want to go?????

-- Edited by oldtrack123 on Sunday 22nd of April 2018 04:11:32 PM

Mike Harding · Guru

You people need to get out more.

oldtrack123 · Guru

Mike Harding wrote:
You people need to get out more.

You, have previously made the same comment .