General > General Technical Chat
Adding earth and RCD to two pin inverter
<< < (3/3)
motorhomer:
So the RVDs look good and a good way to protect on this system. I assume these are not on sale in the UK. Has anyone fitted these
Zero999:

--- Quote from: james_s on August 09, 2021, 07:32:31 pm ---This is one case where it probably makes more sense to refer to "ground" rather than "earth". In a rolling vehicle there is no connection to earth unless you're plugged into shore power. The vehicle chassis is ground but it isn't earth ground.

--- End quote ---
Ground also implies earth to me. They are different words for the same thing. Ground, is more commonly used in the US and Canada and earth, in the UK and Australia. For example, in the UK modern cars are referred to has having a negative, rather than positive earth, as was the case for some vintage models.

If you really want to be unambiguous, you should refer to 0V, common, or chassis, rather than earth, or ground.


--- Quote from: motorhomer on August 09, 2021, 06:16:17 pm ---Ok so I did get wrong terminology,

I agree the RCD will not work without the earth and the way I was going to overcome this was to connect the neutral direct from the inverter to an earth wire giving the three live earth and neutral connections. This will then pass through an RCD and to any appliance so the appliance will have an earth. I do not see any issue with this at first until you get a live conductor short out to the vehicle bodywork then there is a potential lethal voltage on the bodywork which will not be detected until a person touching this body work then touched the earthed appliance.

To over come this connecting the earth/neutral connection to the chassis will make it all safe, but then someone pointed out some inverters are not true isolation between input and output so when the neutral switches to high it will be a short to the battery negative.

On more expensive inverters there will be an isolation like a transformer I expect. So cheap inverters are either to be kept with no earth to make them safe or do not use them

--- End quote ---
The problem is, it's possible the output from the inverter floats, at a DC voltage, with respect to earth/the 0V input terminal, which would result in a short circuit, if you connected the neutral to the chassis.
motorhomer:

--- Quote ---The problem is, it's possible the output from the inverter floats, at a DC voltage, with respect to earth/the 0V input terminal, which would result in a short circuit, if you connected the neutral to the chassis.
--- End quote ---

Thanks I realise the problem with this if the converter does not have an isolating output. We use large inverters at work but they have isolating transformers on the output stage so the negative can and is connected to a chassis for a earth return.

I expect this is the problem with buying cheap inverters. The guy that was asking be the question is now considering buying a different inverter which supplies the correct protection circuits and a earth point
Navigation
Message Index
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod