Question For A Sparkie. Inverter Earth.

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Originally Posted by d2dave

So do how does this work with the Hz. US is 60 and Au is 50. The unit I am getting is 50Hz

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slectable from within the unit usually a twin pack of dip switches or jumpers.

one sets 220v/110v and the other 50/60Hz.

one basic unit one accessory piece and 5 silk screens and you have the ability to have 5 markets covered in one hit.

110v-115v at 60Hz
110v-115v at 50Hz
220-240V at 60Hz
220-240v at 50Hz
and univeral user selectable (plug in the accesory that allows the unit to be controled via the caseing without opening it)

what you most likely don't have is compliance in all of those markets. This is why your inverters manual doesnt come with AS colour codes or specs as the standard (awg VS mm2). One manual fits all models which is why at the back end of the manual it has the tec specs for both.

A transformer rated for 50 Hz will work OK at 60 Hz but not the other way around. It's all to do with the inductance of the transformer at the operating frequency.

Older 60 Hz iron cored transformers would overheat at 50 Hz as they'd draw excessive current.

Dunno about these modern items though.

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Originally Posted by d2dave

Back to my original question. With this plug in type of inverter where does earth go. If an appliance that is made of metal gets a short and is live to its body, where does the earth go?

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the key problem is that's not a plug in inverter its a hardwired inverter. If it was a plug in inverter this whole thread would be moot because you would just wire up the DC side and then plug into the output with a standard connection.

the only answer to your question is

"The earth goes to wherever the installation electrician you pay to do the install puts it."

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Originally Posted by Blknight.aus

the key problem is that's not a plug in inverter its a hardwired inverter. If it was a plug in inverter this whole thread would be moot because you would just wire up the DC side and then plug into the output with a standard connection.

the only answer to your question is

"The earth goes to wherever the installation electrician you pay to do the install puts it."

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I was now asking with a plug in inverter, where does earth end up?

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Originally Posted by d2dave

I was now asking with a plug in inverter, where does earth end up?

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That depends on the inverter, Most plug in inverters now have the -ve DC, inverter body and earth pins of the socket all bonded so long as the -vE DC is a good connection to the main body earth of the vehicle /van your good to go as is, most will earth in a hardwired (as in permanently mounted to the vehicle and permanently wired on the DC side) configuration through the body mounting screws of the inverter and some will have an external earth bonding lug. Connect that to a sound earthing point and youre good to go.

Some (and I havent seen one for a while) dont permit the -v DC and earth point to be connected. Typically these inverters use the body of the inverter to directly heat sink some of the internal components.

the manual for the inverter should tell you what you need to do.

heres a good exmple of the manual for what you should be looking for in your inverter

[ame]http://www.projecta.com.au/site/DefaultSite/filesystem/documents/Inverters/IM150-2000_instructions_Issue1.pdf[/ame]

this inverter series achieves its earth through both the body of the inverter and the DC-ve cable. for use in standalone applications (which is what i suspect to be the case for what you are doing) and earth bonding lug is provided on the body of the inverter.

d2dave, did you see my post?
When not hooked in the mains power it will require an earth stake.

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Originally Posted by Vern

If what ever you plug into it is double insulated then you can get away without earthing it.
Hooking it to the vans earthing system is fine as long as its plugged into the mains.
Not plugged in, then make an earth stake, same as a generator system.
I haven't read the whole thread though.

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That's interesting. I had never heard of the requirement for an earth stake with a generator or inverter. Note, I am not disputing it. I'm glad to know of it. I've never used one with my inverter or gene. Another addition to the camping kit! Does one get one of those long ones from electrical wholesalers? How far does one drive them (and still be able to get them out!)

I wonder how many generators are used at home to keep essentials running in a long black out and how many use a stake? At home it would be feasible/practical to drive in a permanent stake or does one run a cable to the existing stake (if there is one - my house doesn't appear to have one).

Ron, there is no way of getting an earth on the AC side with out it, unless the inverter is wired into the vans ac earthing system then plugged into the mains electricity.
Can't get an earth from the 12v side.

Yes, I understand that but I was thinking along the lines that the system is isolated from the mains - much like when I used to run a live chassis radio open on the bench, I used a 240v-240v isolating transformer. I don't think the earths were connected from primary to secondary. I'll have to check, I still have the isolating transformers in my electronics workshop. In the live chassis scenario, there was no earth lead to the radio.

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Originally Posted by Vern

Ron, there is no way of getting an earth on the AC side with out it, unless the inverter is wired into the vans ac earthing system then plugged into the mains electricity.
Can't get an earth from the 12v side.

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So this sort of answers my original question of how to earth an inverter. A stake in the ground is the only way.

So with a caravan, if an inverter is plugged into the "mains in", as I currently do and I am sure a lot of other people do this, all appliances are operating unearthed.

Vern, I am guessing that you are a sparkie yes? With it advent of the RCD (safety switch) is earthing still necessary?

My understanding of earth is to protect us from a non insulated appliance, in the event of an appliance becoming live, in which case it would short to earth blowing the fuse/circuit breaker.

If there was no earth the appliance would stay live but when touched the RCD would trip.

Am I correct here?

Ron, when I last did extensions they put in a new earth stake. Don't remember how long it was, but it was long, well over a metre and there would only be one foot above ground.

A while ago after a storm we lost power for quite a while, about 7 hours.
Having a caravan park this became an issue, as I need power for sewerage pumps and other essential things.

The SES lent me a generator, probably about 3 Kva and with it came an earth stake which they insisted I use.