Thread: Giandel Pure Sine Wave Inverters

On site, all Gensets have a ground stake driven and it becomes the tie in for portable buildings.

Originally Posted by Tombie

On site, all Gensets have a ground stake driven and it becomes the tie in for portable buildings.

Yes but dependent on application. Gensets that have an MEN fitted are not required to have an earth stake and the regs say 'is not required nor recommended' but local inspectors and site requirements may add one but all fault currents will return to the star point of the alternator.

Driving an earth stake in this situation can in fact increase fault levels if one occurred and cause slower tripping of the main breaker or cause the genset to be unable to supply enough fault current to trip the breaker in a worst case scenario.

Hi folks and first off, until I got involved with RVDs I had no idea that RCDs had so many limitations and short falls.


I am NOT an electrician so I was not aware of how RCDs worked, beyond the basics, but more importantly, how they didn’t work. Their biggest drawback is that in many wet situations, they do not function as expected and in many cases, they just don’t work at all.

RVDs correct this problem.


Another drawback and again, something I was not aware of, is that RCDs will only give full protection for just one single Class 1 appliance, and for every additional Class 1 appliance connected to the same circuit, you get a proportional reduction in protection.


Put another way. You get full protection when only Class 1 appliance is connected to an RCD, If a second Class 1 appliance is connected to the same RCD, then you halve the RCD’s ability to protect that circuit. Add a 3rd Class 1 appliance and the RCD’s ability to protect this circuit is now down to one third of it’s intended protect.


Whereas with an RVD added to the RCD and you now could have one hundred Class 1 appliances connected to the one RCD and because the RVD is in the circuit, all one hundred appliances are FULLY PROTECTED at all times.


Now to inverters and how to set them up.


First thing, and this needs to be done by a competent electrician, the MEM link needs to be REMOVED, then an RVD-EI, mounted on a suitably sized RCD, is connected to the output of the inverter.


Again, this is a job for a competent electrician, not a job for a home handyman!


By installing an RVD in this manor on an inverter or generator, they then become a floating circuit and L1 and L2 are fully protected.

Sorry Drivesafe but ALL electrical installations SHALL - by law - have an MEN link fitted. Caravan installations are not exempt from this. When a new van is built here in Vic it requires a Certificate of Electrical Safety - which involves checking the MEN link is in place on the isolated supply side (not the mains connection side) amongst other things when an inverter and changeover switch for a genset is fitted.

RVD's are an important safety feature depending on the installation yes but they cannot replace or override Australian Standards.

As an Electrician myself that advises a National company and its customers there Electricians and Inspectors about the correct installation of generators in a multitude of applications, I cannot advise this under any circumstances.

If you read the latest release of AS3010 you'll see there is a huge amount of info on how isolated electrical systems should be wired and all of them include an MEN.

And your summation of how RCD's work is also incorrect. They act on a balanced circuit so as soon as it sees a difference of 30mA in any part of the downstream circuit between active and neutral they will trip regardless of how many appliances are connected. We can have over 100 appliances running on a circuit at an event and one slightly dodgy appliance will still trip the RCD and testing these circuits shows they are all protected.

Hi Homestar, and the RVD-EI is approved in Australia under the existing standards, for use with inverters and generators, as I posted.


RVD-EIs have been approved for the last 5 years, but, MEM use is now being questioned because of safety reasons, where having an MEM in some inverters can allow 240vac to connect to 12 batteries in certain fault conditions, and this is one of the reasons why AS3017, which was out earlier this year, is now being held over while the standards are being examined.

This has nothing to do with RVD use, but removing the MEM to make an inverter safe against 240vac getting into the 12v system makes RCDs useless unless an RVD is installed with the RCD.


BTW, when an RVD-EMR is installed in a caravan in Victoria, you no longer need to fit double pole switches and power points. Victoria is the first state to introduce this.

As I pointed out, I am not an electrician but I need to keep up with what is happening and I do this by keeping in touch with those working in this area.

Not saying RVD's are a bad idea - far from it. You'll get no argument from me there - they provide a level of protection above RCD's - that's not in question.

My problem is removing the MEN link - this illegal under current Australian standards - including the brand new AS3010. The new version of 3000 will be out in the new year but I would be surprised if it goes against another standard that's just been released. Our company sits on the standards committee for 3010 but not 3000 so I've only seen the draft.

I see where you're coming from - but until the standards say you can or can't do something - as a qualified Electrician with 20 years full time doing isolated power supplies, I can't endorse the kind of system you are describing in its entirety.

Yes, get an RVD fitted when you get an inverter fitted - no argument there.

Hi again Homestar and I think the problem is that I am not explaining their use properly, and I will leave it at that.


But they are being installed in new ambulances and fire trucks. QR has been using them in the work trucks for a few years now and they are being used in special services police vehicles in NSW, to name just a few areas where they are in use and where they have to meet the standards.

Interesting discussion guys, thanks.

I will be fitting a RVD-EI with a 15A RCD to the output of my inverter. As I am not installing a changeover switch, it will require the normal caravan power lead to connect from the inverter output to the normal caravan mains input (KISS principle, can't plug more than 1 plug in at a time). This way will prevent accidental connection of shore & inverter power simultaneously.