RCD's What do you use What do you think

[Rider]

The test button on a RCD (GFCI) is only there to test that the device itself can react to an imbalance in the active/line/live and neutral current. It does this by, typically, hooking a resistor between active and neutral across the sense transformer so that there will be an imbalance in the current flowing the active and neutral winding in the sense transformer. That's all it does. It is not testing any other part of the wiring and earthing system. That it trips is no indicator at all of the overall safety of the entire system.

A test plug that you put in a socket to see if it will trip the RCD is again only a partial test. It only shows that the neutral and ground are bonded upstream of the RCD under test and that the RCD can detect the imbalance caused by passing current around it via the earth wire. Its important to understand that this is not a full test of the installation. If the earth system is not to spec as per local regulations the RCD can not offer the full level of protection it normally would.

Gotcha.

 

[gnubie]

Even worse if the neutral ever has a fault, everything will continue to work but you'll have all the current on the ground, which also means that you can now be electrocuted by touching the panel chassis, for example, peace.

There have been several instances of this happening in Australia where we use the MEN system. A lot of houses have galvanised pipe plumbing and use it as the earth stake. If the neutral into the premises faults or goes open all the load in the premises will be returned via the earthing system. This can result in the entire earthing system being raised up to dangerous voltages.

I know of a unlicenced tradie in my own town that had one of his crew replacing the gal pipe in from the street. The person did not follow, nor was even aware of, proper procedure. There was a neutral fault, he cut the pipe which while not fully breaking the earth return allowed dangerous voltages across the break, and then he grasped either side of the pipe and received a severe shock, fortunately non fatal and no permanent harm.

A neighbour across the road had a neutral fault develop while she was in the bath. She reached up to the tap to run some more water and found her hand latched onto the tap and could not release. The current path was across the earthed water pipes and the metal drain pipe because someone had not correctly wired the premises. That danger lurked for nigh on 30 years before making itself apparent.

A well publiicised event recently where a neutral fault developed in a housing commission (government funded housing) house caused the plumbing of the house to raise up to dangerous voltages. A young girl received permanent brain damage as a result of grasping the handle of an outside tap.

 

[offgriddle]

There have been several instances of this happening in Australia where we use the MEN system. A lot of houses have galvanised pipe plumbing and use it as the earth stake. If the neutral into the premises faults or goes open all the load in the premises will be returned via the earthing system. This can result in the entire earthing system being raised up to dangerous voltages.

I know of a unlicenced tradie in my own town that had one of his crew replacing the gal pipe in from the street. The person did not follow, nor was even aware of, proper procedure. There was a neutral fault, he cut the pipe which while not fully breaking the earth return allowed dangerous voltages across the break, and then he grasped either side of the pipe and received a severe shock, fortunately non fatal and no permanent harm.

A neighbour across the road had a neutral fault develop while she was in the bath. She reached up to the tap to run some more water and found her hand latched onto the tap and could not release. The current path was across the earthed water pipes and the metal drain pipe because someone had not correctly wired the premises. That danger lurked for nigh on 30 years before making itself apparent.

A well publiicised event recently where a neutral fault developed in a housing commission (government funded housing) house caused the plumbing of the house to raise up to dangerous voltages. A young girl received permanent brain damage as a result of grasping the handle of an outside tap.

Oh my those are chilling stories to be heeded. To properly ground is divine. We have to all be cautious when working our own electrical systems and not everyone is proficient at all things and when it comes to electrical safety we have to know for certain what we are doing or we cannot play electrician, no matter what our ego tells us.

 

[b.james]

So can somebody please answer my question as to what works to ensure my inverter trips if a little hand sticks a fork in the outlet?

I want to be sure no one can get electrocuted by my inverter supplied power . I use a cheapie chinese made 2000 watt atm. What do I need to buy and attach?

 

[offgriddle]

So can somebody please answer my question as to what works to ensure my inverter trips if a little hand sticks a fork in the outlet?

I want to be sure no one can get electrocuted by my inverter supplied power . I use a cheapie chinese made 2000 watt atm. What do I need to buy and attach?

Hmmm to ground is divine:
~~ Firstly, follow the manufacturers recommendations for connection and grounding.
~~ Directly connect the inverter negative and positive DC cables to the battery, fuse the positive cable.
~~ Directly connect the negative and positive DC cables from your charging source(s) to the battery, fuse the positive line.
~~ Run the AC output of your inverter immediately through a GFCI, (a standard 15 or 20 amp gfci outlet available at hardware stores will suffice).
~~ Test the GFCI to make sure it operates with your inverter.
*****************************************************************************************************************************************
~~ If this is not a stationary application, it's a good idea to ground the battery negative battery terminal to an earth ground.
~~ Note: many inexpensive consumer-grade AC inverters will NOT allow the Neutral output conductor to be grounded. That is because the internal DC-DC converter is not isolated from the output stage. In these inexpensive inverters, the Line & Neutral terminals alternate in polarity between the DC ground line and the high-voltage positive output of the internal DC-DC converter. Attempting to ground the Neutral output conductor results in either blown fuses or blown output switching devices, (in other words keep the neutral and ground separate).

 

[offgriddle]

There have been several instances of this happening in Australia where we use the MEN system. A lot of houses have galvanised pipe plumbing and use it as the earth stake. If the neutral into the premises faults or goes open all the load in the premises will be returned via the earthing system. This can result in the entire earthing system being raised up to dangerous voltages.

I know of a unlicenced tradie in my own town that had one of his crew replacing the gal pipe in from the street. The person did not follow, nor was even aware of, proper procedure. There was a neutral fault, he cut the pipe which while not fully breaking the earth return allowed dangerous voltages across the break, and then he grasped either side of the pipe and received a severe shock, fortunately non fatal and no permanent harm.

A neighbour across the road had a neutral fault develop while she was in the bath. She reached up to the tap to run some more water and found her hand latched onto the tap and could not release. The current path was across the earthed water pipes and the metal drain pipe because someone had not correctly wired the premises. That danger lurked for nigh on 30 years before making itself apparent.

A well publiicised event recently where a neutral fault developed in a housing commission (government funded housing) house caused the plumbing of the house to raise up to dangerous voltages. A young girl received permanent brain damage as a result of grasping the handle of an outside tap.

"An Unlicenced Tradie", lol I love that term, I so love quaint colloquialisms!!
~~ You are correct, people who work with dangerous utilities that could maim and kill definitely need to know what they are doing and either be sufficiently experienced or be working under the direct supervision of sufficietly experienced and licensed personal and also have access to obtaining *reasonable experience and credentials for themselves.
~~ *Reasonable Defined: Some of the U.S. states may be reasonable in the area of licensing I'm not sure, whilst others require paying a pound of flesh to the state Commmunistic authorita and the lowest common denominator private labor cartel that controls the state's licensing processes. In other words, a capable individual seeking to become a professional electrician shouldn't be forced to go into hock to the state's Communistic education monopoly just so that the Communista can have jobs and fleece the common core clueless slave proletariat intentionally created by the communistic, public, education monopoly, such as has generally happened in the states! It's extortion I tell yah! Stay Free!

 

[svetz]

Short Circuits vs. Ground faults
A short circuit is what happens when a hot wire touches a neutral, ground, or out-of-phase wire. Normally, all hot wires are fused (or on circuit breakers), so the current flowing through the hot wire should cause the fuse to trip.

But, if the resistance is high enough, you can have a lot of current running though a wire that will NOT trip the fuse. GFCIs (aka RCDs) are for Ground Faults. They open the circuit when there is an imbalance in current flowing as depicted below.

​

Note that in the diagram above, if the fault occurs before the GFCI the GFCI will not interrupt the circuit.

How does a ground wire keep you safe?
If the hot wire comes lose and makes contact with a grounded surface it will short-circuit and trip the circuit protection. If it weren't there, you could be it's path to ground. Note that the "Earth" has a lot of resistance, so the ground wire is also bonded to the neutral wire (usually at the load center). Metal appliances (e.g., toasters) have the metal shell bound to ground for the same reason - if your toaster doesn't have a ground wire and the hot wire touches the shell, you become the ground for it.


Why doesn't my GFCI tester trip the GFCI?
Defective or wired backwards. ref If the tester creates the imbalance by resistance-shorting to ground, and there is no ground wire ref

So can somebody please answer my question as to what works to ensure my inverter trips if a little hand sticks a fork in the outlet?

That's what I got from my internet searches anyway. Seems like your best bet is an RFD, a good ground, and keep the breaker amps as low as possible. Hope that helps.

 

[b.james]

Yes it does svetz Thanks

However I have now been sufficiently frightened by obvious posters to wonder, well how do I connect my inverter and indeed my compete solar system to earth safely without blowing up my inverter . Putting an earth rod in is no problem or attaching to the houses earth rod ,simple enough.

The present system (this inverter and solar panels ) is not earthed yet and I'm wondering how to test that without destroying my inverter?

 

[b.james]

I got a little more by watching this guy in the States discussing a Pulse Modified Wave Inverter being attached to a house wiring system .

It discusses the waveforms on the active and the neutral and the ground system (again in the States where neutral is tied to ground in the meter box) so I'm gonna see if I can find a way to test my inverter. My power here is Single Phase 240 Volts. My inverter is a Pure Sine Wave type. So apart from testing resistance , neutral to ground I don't think I can get much more from this. We'll see.

How NOT to Connect an Inverter to Your House Mains - Xantrex ProWatt Inverter part2

 

[svetz]

Happy to help, I'm sure the image helped.

Modified vs. pure sine wave really doesn't have anything to do with the safety aspects AFAIK. What the video is showing generally a bad idea and in the states can get you into trouble. If you want to do that I suggest an ATS.

I'm not sure what your trying to accomplish? Is it that you want to test the RCD you have to make sure it is in good working order? Or is it that plus your house doesn't have a ground (earthing rod)? If your climate is really really dry, there's a thread I saw on an ufer ground that might interest you; you should be able to find it by searching.

 

[b.james]

I'm not sure what your trying to accomplish?

svetz.
I would have thought that anyone reading the thread would have known my question clearly by now so you are obviously being facetious and trying to bait me and avoiding an answer altogether.

My house is earthed thank you . My grid is 240 Volt single phase thank you .
My solar is not earthed thank you . My environment is the wettest place in Australia and I get 6 meters of rainfall a year average so no I don't think you would describe it as dry albeit it is as dry as it ever has been right at the moment thank you.

I want my RCD to work so I need to know whether to earth my inverter or not and my panels.
I wish to accomplish a safe environment if my kids stick a fork in an outlet that I have provided from my solar.

Now if that's not clear enough for you I suggest you start at post 1 and read it through again to your post which is number 30 thank you.

Everyone on this forum feeds power to their appliances and equipment if they have installed a solar system and those people need to know if they are going to electrocute their family or not ?

 

[svetz]

svetz.
I would have thought that anyone reading the thread would have known my question clearly by now so you are obviously being facetious and trying to bait me...

Wow! Sorry you feel that way.

Good luck getting help from anyone when you insult those trying to be helpful. Here's my advice, go out and pay an expert to answer you.

 

[b.james]

Good luck getting help from anyone when you insult those trying to be helpful. Here's my advice, go out and pay an expert to answer you.

So thats a bit contradictory isn't it ? You don't want to answer me because you feel insulted but I should follow your advice and seek an expert.

Hmm OK . I'm not insulting you . I can do much better than that.
What I'm seeing is a moderator "wall" up to protect each other and back up each others posts .
Nothing wrong with that either and its nothing personal but I am still looking to answer the original post after 32 indifferent posts now.

I'm finding out for myself what is needed in Australia to ensure toddler safety anyway and frankly it should be considered a very serious matter of safety and should be covered by clear and unequivocal answers to advise members what to do in each and every country that might be represented on this world wide board.

Its easy to start up a board at the moment and have it broadcast to the world . Along with that comes a responsibility then to run it in a fashion that is suitable for a worldly audience not just an American audience.

I'm leaning toward the reason for your reluctance being more Insurance motivated . Probably stemming from being instructed not to go into anything that might bring legal repercussions . Thats OK too .
The only point is why not own up to that being the reason and stop the subterfuge and malarkey.?