Inverter RCD test and explanation 

Hi, Neil from Oz. Placed my ute camper(truck camper) on a tandem trailer because of weight issues. As a retired electrican, I set about upgrading electrical system. New code says inverter must be protected by rcd and have a remote control, I had already bought a new inverter and it is centre tapped. It did my head in about the Rcd protecting the circuit. The inverter is not neutral earth bonded and manufacturer was very vague on earth faults except recommending I earth it to trailer. The inverter is stand alone and powering two stand alone inverter outlets. It did my head knowing an RCD would not trip on fault. After a lot of research came across a very expensive approved device called an RCD DUO which works on sensing 40 volts to earth which about 10 ma. Your video is very good in letting a lot of people know that RCD's do not protect most inverters. The RCD DUO is also used on inverter generators.

A VERY simple explanation of a dark art that shouldn’t be a dark art.

Just wanted to say thank you for this. I have been scouring the internet and reading through old forums but none if it quite made sense until this video. This is exactly why I won't be installing my modified sine wave inverter by Krieger. 'Twas expensive, but I'd rather bond my wallet to victron instead of my body to the van. Thank you!

Great video, thanks for sharing your knowledge and experience. Glad to see I have wired the setup in our Motorhome the same way. Although, I am using a cheapish Chinese pure sinewave inverter, the chinglish destructions advise the case to be grounded to the vehicle chassis. So now the geek in me needs to get an RCD tester and Martindale to see how safe and efficient it is.

Very brave of you to tackle this on YT nicely done ✔️ 👍

Cheers for that, very informative. I do like a good public service announcement 😁

Even though you know in yourself that you have made a very good electrical system in your own van, along comes Jeffers with another in depth testing video to cast a tiny nagging doubt in your mind. Tomorrow’s task: insert wet tongue into van 13 amp socket to test trip switches again.

We use an RVD in Australia to give earth fault protection on the 250v output of an inverter, our regulations don’t allow for neutral earth bonding of the output side of an inverter, the RVD(Residual voltage device), the RVD is a combination 2 pole, DIN rail mounted unit, with overload, short circuit and reverse polarity protection included. It covers all your electrical protection requirements in one device.

Earthing the van is even more important when using shore power. When using 110v Centre tap (tool) power supplies double pole MCBs are used to protect both live conductors.

"If you get DC wrong it burns your van down. If you get AC wrong it kills you, then burns your van down" 🤣 Brilliant (and true!).

Nice couple of vlogs - testing you have done. Been doing a lot of research on this myself. Shocking how some inverters provide no PE protection and people fit RCD and think they are safe. From What I can see so far Victron and Sterling are the only inverters I know that provide the PE setup unless you know of any others. I expect the centre tap in the Sterling is as you said reduced voltage shock to below 110Vac which is below lethal voltage legally but but would not want to test that 😂. In Australia they have a RVD safe system which looks good for converters. I think Sterling might have this as well but not checked yet. Anyway thanks for doing the Vlog looking at a larger off grid system so will need the RCD protection

By the way. Short-circuit protection (overcurrent) ( Fuse or MCB) are devices that the user should have installed. Usually placed everywhere in-line between all power sources and all power consumers. Its like saying the inverter should have its own RCD ??? Perhaps one day ? Nuff said !

Very interesting... plenty for people to think about. 2 comments to make... 1.. where's the intro..!! 2. .. loving the "action" call.... maybe "cut" could also be added at the end... 😁😁 Cheers 👍🏼😊

At 11.55 good description of the concept, but it also relates to Neutral and earth faults equally.

Hi Geoff. I just bought a 3kw Inverter (Double Insulated) it says Class II only, but I intend to make it TN S (Earth Neutral bond) as I may at some time want to use a Class I device. I intend to use proper distribution, so it will have Double pole MCB and a type A RCD. I use a robin RCD tester. I was testing Caravan hook-ups on a local site, at one particular stand, yes the mechanical button worked, but my Robin said NO!. Upon further investigation, I discovered who ever installed that particular point, did not connect the CPC from the source. (So no Earth), a couple of hours later, I found it further up the line. Yes it was TT, but there was no connection at all to CPC. The Robin tester was only £30.00 and has proved very useful. David in Skegness Lincolnshire

The reason the Renogy inverter does not work in the first case scenario, is that it is designed to work with double isolated loads, like computers, phone chargers, etc. Thus, it's not intended to connect e.g. a refrigerator, electrical hand tools, etc. The more (expensive) ones allows you to use the RCD in this latter load case. Cheers, and I and cannot agree more. I find way too much misinformation floating around on YT on this subject. Subscribed.

Grounding Bonding and earthing are often interchanged but each means totally different things.

Great explanation Geoff really enjoyed it hop you both have a wonderful New Year!

Would be really interesting any videos on DC breakers more interestingly the polarity type and arc quenching devices ,its still a misunderstood topic :-)👍

Hi, thank you for this video. My guess is that, in the case of a center-tapped inverter, the RCD is not tripping maybe because a 30 milliamps current leakage between L (or N) and earth/ground at 115 V (that is what the RCD tester will cause) is half the power (30 milliamps at 230 V) of what the tester is calibrated for (so maybe when it is set to 30 mA it is leaking just 15 mA between L and Ground). I would make a test setting the residual current at 60 milliamps or more, and see what happens. Another thing I would love to see, if you can, is investigate how a 120V RCD (that should be what is used in USA) behaves with the same 30 milliamp leakage. Thanks a lot in advance for any response, Attilio

Very informative and well explained 😀👏love your work 🤩just subscribed 😀

Absolutely brilliant Geoff very well explained and solved a long mystery for me 👍 it would be good if there was a socket tester that works for the inverter type/wiring scenario ( rather than using the adaptor device for the multimeter ..was it a marydale )

Did you hear that,.... A penny just dropped... Finally!! an explanation; nice to know I did it right and connected the inverter Earth wire to the van. Now i just need to know why my portable induction cooker trips the Van rcd sometimes when I use the inverter. perhaps it's not a realy good "pure sine wave"??

I did a really long ( but informative) comment but my crappy windows laptop just blue screened on me. Essentially, the inverter is not at fault, its the lack of Earth-Fault-Loop-Impedance capability. The inverter would need a Neutral to Earth Bond ( maybe via a relay/contactor for Grid hook-up disconnect) . My house has a 20kw battery and 3.6 kw inverter, which can power my home using off peak electricity saved for use during the daytime.. Even that needs an NE bond in case the Grid is switched off ( in island mode during a power cut) reason the mains trips the RCD is because the generator at you local substation has the neutral and earth combined and/or centre-tapped so they meet at the source. The RCD measures any imbalance in the circuit via Current leakage through the CPC ( earth connection)(circuit protective conductor) and disconnects its (looped) mains supply. The inverter ( as most are) is meant by design ( for safety ) to power class 11 appliances ( double insulated) so a neutral to earth bond BEFORE the consumer unit is needed to achieve the same test function. Many folk including some sparks don't consider this ! And I would say YES to separately "bonding" the Consumer unit output earth (CPC) to the vehicle metalwork/chassis so any AC fault conditions ( wire rubbing against metal parts of the van) will be detected by the RCD and disconnect that supply. The DC circuits usually have chassis "grounding" to serve as the negative for the whole vehicle ( see battery negative bolted to your vehicle ?) This is perhaps why Double-Pole ( Line & Neutral) AC breakers are now called for. Always keep these AC / DC Bonding connections separated though, and "bright and tight" is the way to connect! Id say get a qualified and/or competent person to check and test the entire installation before use !

Really useful. Just need to add that to the tick list of what inverter to buy when I have saved enough to get my new van

Hi guys really enjoying the videos. Been a while since this one came out when is your next instalment? Hope your all ok x

Sorry bud only just watched this (never came up on my reminder for some reason 🤔) Excellently explained matey 👌👍😎"👊".

Great flix guys. Happy new year. X.

Mains polarity ( especially when abroad) needs to be confirmed when hooking up. Proper leisure Consumer Units have a neon lamp to confirm this for you. Also the correct rcd and Miniature Circuit Breakers (MCB) ratings will be fitted . Usually 30ma Rcd at 16 amps. 1 x MCB at 10 amps plus a second mcb at 6 amps. All in a properly labelled, insulated (lightweight) plastic enclosure. Going to leave you all alone now ...LOL

My dad lives on a boat, as you know, and every 4 years you have to get a saftey certificate, last year my dad's failed. and one of the things it failed on was the plug tester showed there was no earth so it failed. I did some research and found out that a nuetral earth bond was needed. He has a victron. So in the plug for the inverter I neutral earth bonded that and it passed and has worked ever since. So in theory you can just do that rather than buy the sterling? That's at least what many others had done when I google it. Very helpful vids though Adrian! Learning lots as I don't know so much about 230v AC! Thanks!

Its called E.E.B.A.D.S Earth Equipotential Bonding Automatic Disconnection of Supply

Very useful - many thanks

Hi there, Love your videos and sorry for the two dumb questions...1. when you say "you should earth your van" how in practice is this done given that the van is isolated from earth? 2. Does the van have to be earthed (as above) for the NE Bonded Inverter to work, or if not, how does it actually work please. Many thanks

Great explanation, Renogy have said not to use an RCD on the inverter output, but it has inbuilt safety but won’t elaborate on what that it. Not sure if i should get rid of it it just accept it’s safety limitations and double insulate everything. It seems a great inverter otherwise. Also theres an earth/ground screw on the inverter that again isn’t explained in the installation instructions.

So, i have a victron multiplus inverter/charger, which has a neutral/earth bonding relay, which operates depending on whether it is being grid fed or inverting only. The casing of my inverter/charger, plus my MPPT solar charge controller casing, plus the DC cable link to the negative side of the battery all go to an earthing(grounding) busbar, and then a single cable from the busbar to the vehicle chassis. I have read however, that i need a seperate earth cable from the inverter casing to a seperate vehicle chassis point, for the 230v earthing. I've had the RCD testing done by an electrician(not an auto electrician, only household) and he was very surprised at how quickly it tripped without an earth rod connected. Is this 'extra' earthing cable definately required from the sole 'inverter casing' earthing point or does the current cable connection, but through the grounding busbar suffice? It seems weird to me to have two different earthing cables connected to the one casing connection, but to two different points on the vehicle chassis at the other ends. Appreciate any pointers given. The Victron 'wiring unlimited' guidance is as per what i have, but many sparky's are saying that a seperate 230v earthing cable is needed.....not shown on victron guidance. Appreciate any clarity you might offer.

Thank you for the explanation and duly understood, however, being the owner of the same renogy 2000w inverter, what is the solution to the problem when off grid and no earth is present rendering the RCD useless, at home in an off grid scenario, you simply link the earth and neutral together inside the consumer unit creating TN-S, but what if there is no earth, i.e. in a van with no shore power connection?? many thanks.

you did a video before where you fit the renogy inverter to your van that a lot of people followed, with no information at the end that it was only suitable for isolated devices or emergency situations, but here you are with a video of the dangers of that same inverter you fit into your van, is it not a good idea to go back to the video of you fitting the renogy inverter into your van and referencing this video?

Hi. Cheers for the informative video. I’ve got the same inverter and was going to install a double cut RCD consumer unit to output of the inverter for my self build van. Will earthing the RCD to ground help.

If you have got an inverter that is not n/E bonded, can you n/E bond at the consumer board?

Could you do a further test with the Renogy setup and gradually increase the RCD current. I think it should trip at about 60mA. I noticed on a site transformer that had an inbuild RCD there was a label that said not for 240v use. As the centre tap on the inverter is giving +/-120vAC rather than +240vAC maybe the RCD test needs more leakage current to trip.

GFCI Ground fault circuit interrupt

We made one that going in motorhomes at Roadpro

Hi, I have just spent an hour on the phone to Renogy US. They have confirmed that an RCD does not work with the Renogy inverters. They have however stated that there is a build in GCFI (American equivalent of RCD) which works both on battery and EHU. How would I go about testing this (as in would you be willing to test this)?

Is there any SAFE way to use centre tapped earth inverters? What’s the point in them if they’re this dangerous?

I have just order a 3000 watt renogy inverter, how would I set it up to trip the rcd? Cheers

Did you ever try connecting the inverter chassis ground to the AC earth circuit? My understanding was this is how it should be installed and woudl trip the inverter if there was an earth leak?

In the renogy example can you not earth the inverter side of the RCD?

Either way, the van's getting burnt down😂😂😂

Aww. I just unsubscribed because despite your vast knowledge, not all that you are preaching is accurate ! Sorry mate. Cant support vague guidance.