RCD - How safe?

[shakergt]

Can you imagine me calling an electrician to Cue from the nearest town Meekatharra just 115km away and asking to have my home electrics checked out. I might get lucky and actually get onto somebody who cares enough to tag my job on to somebody else's but the best chance is that we'd both be charged 3 hours travel for a job that could likely be knocked off in under an hour. Even that mightn't be too bad if you actually got a decent tradesman but I know the odds

Moneybox get your electrics tested. I know what you are saying about travel but you will kick your self if someone gets seriously hurt or killed just because you did not get your electrics checked out. I have sent you a private message regarding a voluntary recall on a RCD manufacture. Hopefully this is the case for you. I will also add that the recalled RCD will sometimes function fine when the test button is used.

 

[19.3]

Crikey - sounds like you've been having fun!
Not surprising the first test (with the stainless connection) didn't work - concrete was probably not conductive enough. If it was wet it probably would have worked - but that could also prove fatal for the tester!

The RCD has 2 modes of tripping - the first is if the current flowing thru the wires exceeds the current rating of the unit - this is probably feeding several of your house circuits and therefore quite a high rating - which would explain why it didn't trip on the first flash in the wheel barrow.
The second mechanism is the current that leaks to earth which was not high enough - presumably since the path to earth from the stainless cabinet was too high resistance. A short flash between active and earth wire in the wheel narrow would prove your rcd earth leakage was working - but your test button on the rcd would also do this - and would not put your life at risk.
...and seriously, I would not be using the grinder again until tested by an electrician with the proper test gear which accurately measures leakage current. You don't get 'immunised' by getting a few 'belts'!

 

[Booney]

Hey Moneybox , sounds to me like you have created enough earth potential with your body and the wet concrete to allow some current to flow through your body giving you that shock . But not enough , less than 30 ma to trip the rcd with residual fault current . You are very lucky my friend and I dont need to tell you how dangerous that situation was and you should never trust an rcd or work with power tools in a wet environment .There could have been many factors at play here , not enough water or clean water to make true earth , concrete on plastic , fault in electrical circuit , moisture in soil who knows . But one thing for sure you are one lucky bastard , to get a shock through the heart can be Fatal . As electricity takes the shortest path it may have travelled down the outside of your body though sweat or damp cloths again who knows but your heart is just a mussel and will contract with electric shock and sometimes not start again. Scary stuff , Please do not try simulate a fault this could easily go wrong.
I do agree your wiring needs to be checked but understand your remote situation. Here is something you can do if you can get your hands on one of these its a cabac polarity and Earth leakage tester . There are better and more sophisticated testers on the market this is just a basic and good indicator of polarity and fault current . First press the trip button on rcd allow to cool then reset.
Plug in tester to power circuit check polarity center and right side indicator light should be on all good turn dial to add 5 ma of fault at a time till rcd trips allow to cool , reset and test next outlet and or lead .
Rcd should trip out at 25 - 30 ma if not or in doubt call electrician ASAP . Bit far for me to come but could post my tester if required.
Cheers mate stay safe Booney

 

[Nightjar]

MB, Here is a tragic example resulting in a death and a near miss.
Back in the 70's a work mate was erecting a patio on newly built home. The drill he was using had the chuck key wired to the electrical cord. He used the chuck key and fell off the ladder. His young boy new something was wrong because his father was writhing on the ground. The boy ran next door to raise the alarm, the neighbour came running and removed the extension lead from the socket. Unfortunately the father died at the scene.
A colonial inquest found the chuck key being wired to the drill lead and the continual flexing of tightening and loosening the chuck had worn through the insulation exposing live wires. Natural reaction when receiving an electric shock is your muscles contract. In this case his fingers tightened around chuck key and was locked in his had. Tragic loss of life!
Move forward 12 months, the mining company I worked for organised for electricians to install the then new RCD units in any family and friends houses who were interested.
Purchase the RCD and it was installed free.
My parents lived in a pre WW2 home and I organised the installation. Some time later my father informed me he had called an electrician to come and remove "that stupid device" I had organised because their power tripped occasionally. Needless to say I explained to Dad that there must be an electrical fault.
I rocked up with a company electrician and he turned the mains off, refitted the RCD and removed every device plugged into a power point. Then power back on and all the utilities and gadgets plugged back in one by one. The power didn't trip.
Mum offered myself and the electrician a cup of tea which we accepted. All went well until Mum opened the fridge and low and behold the power tripped.
An investigation revealed condensation was collecting around the interior light and the power leak tripped the RCD.

 

[PabloP]

Too many people, and many of them tradesman, are just doing a job for the sake of having a job and the outcome is rarely good. Then I suppose these people may need somebody to hold their hand when it comes to looking after the gear as well. Never mind, it's a practice I don't agree with.

I do understand your point and in fact there are other related matters that may be worth mentioning.
One of the people who does vollie work with the same organisation as me, was an electrician until a couple of years ago, but he was not keen to do any test and tag work, said it was too boring and time consuming.

I ended up working out that the real reason was that he didn't really understand the nature of the issues that Test & Tag were trying to find, and was not confident in his abilities. He had worked in a job that was "cookie cutter" type sparkie work that he knew and understood and didn't keep up with the wider scope of work that a sparkie may have to do. So his response was the correct one. Those responsible for the effective completion of Test & Tag work, must be confident that the person conducting the work, is capable and competent to effectively carry out the work required. So just because someone is a sparkie doesn't mean that they can do the work properly. Besides purchase of copies of the Standards to bone up on things is not cheap, which is one of my main bug-bears.

Following on from the actual experience that you had, there are special tests that must be carried out on equipment that is operated in a submerged environment especially for Class 2 gear (Double insulated and typically no earth pin), and many people (sparkies) are not aware of these tests or their required use as they were only introduced in a modification to the re-written AS/NZS 3760 standard in 2011 I believe.

Now while your Xu1 was not actually immersed, the potential for water to bypass the double insulation properties clearly did exist, so the situation that you experienced is not one that is likely to have been considered by the manufacturer and would not show up with normal test & tag work.

As an aside the number of electrical standards that exist and their special applications, is quite extensive, with AS/NZS 3000 being the base one then AS/NZS 3001 that basically cover trasnportable structures & vehicles; and AS/NZS 3002 shows & carnivals; AS/NZS 3760 for so called "Test & Tag", etc. Even within the Test & Tag standards there are variations that cover special cases, such as medical equipment. To add more confusion specific industries have implemented practices to address what they believe are higher risks and they even confuse the inspectors. eg. get an inspector with a building industry background inspecting a campground environment and you are likely to get a bun fight, as he may apply his practices rather than those applicable under AS/NZS 3001.

As you can see it is an area that is open to a lot of "disussion" and my approach is always to do what will avoid an issue that could cause damage to people an/or equipment.

Rob P.

 

[Moneybox]

Hey Moneybox , sounds to me like you have created enough earth potential with your body and the wet concrete to allow some current to flow through your body giving you that shock . But not enough , less than 30 ma to trip the rcd with residual fault current . You are very lucky my friend and I dont need to tell you how dangerous that situation was and you should never trust an rcd or work with power tools in a wet environment .There could have been many factors at play here , not enough water or clean water to make true earth , concrete on plastic , fault in electrical circuit , moisture in soil who knows . But one thing for sure you are one lucky bastard , to get a shock through the heart can be Fatal . As electricity takes the shortest path it may have travelled down the outside of your body though sweat or damp cloths again who knows but your heart is just a mussel and will contract with electric shock and sometimes not start again. Scary stuff , Please do not try simulate a fault this could easily go wrong.
I do agree your wiring needs to be checked but understand your remote situation. Here is something you can do if you can get your hands on one of these its a cabac polarity and Earth leakage tester . There are better and more sophisticated testers on the market this is just a basic and good indicator of polarity and fault current . First press the trip button on rcd allow to cool then reset.
Plug in tester to power circuit check polarity center and right side indicator light should be on all good turn dial to add 5 ma of fault at a time till rcd trips allow to cool , reset and test next outlet and or lead .
Rcd should trip out at 25 - 30 ma if not or in doubt call electrician ASAP . Bit far for me to come but could post my tester if required.
Cheers mate stay safe Booney https://www.prospectingaustralia.co...3544_9ca7c491-5147-42df-90c1-e06d4977467f.jpg

Ok Booney, now you've got my attention. How does this look?

A SOK36AU Professional Socket, Earth Loop, Polarity & RCD Tester is an ideal accessory for any Portable Appliance Tester. It is designed to identify a variety of faults with socket wiring, but most commonly used to reveal sockets with poor earth. Simply use your PAT Tester to test one socket of an extension lead and use the SOK 36 Professional Socket, Earth Loop, Polarity & RCD Tester to test the rest! A Socket Tester really speeds up PAT Testing.

Bright LED's out-perform fragile old style neons
Easy to use 5 test functions
Tough smooth contoured construction
Logical "Green for Go" LED indication
New circuitry means no tripping RCD's
The first socket tester to show where the actual fault is Live , Earth or Neutral
New patented "Fault Locate" electronics gives clearest indication yet of good plus 17 wiring fault conditions - more than any other known socket tester
Continuous or strong warbling tone gives positive quick indication of good or faulty wiring
Built in self check at start of testing gives confidence in correct operation at all times
The first socket tester to also test true earth loop impedance
Compact design encourages more frequent socket safety checks
Audible tone indication gives clear indication of good socket or problem socket
Test for total supply system polarity safety
Operational check of 30mA RCDs
Full earth loop check

I appreciate the offer but I won't borrow gear

 

[condor22]

1. Typical home wiring in Australia is performed with "Neutral Earth Loop" when done to Aust Stds.

This means that the Earth and Neutral at the meter box are connected.

2. A RCD does NOT need an Earth connection to operate effectively..... RCDs work by sensing an imbalance between Active and Neutral and as Earth is a part of the Loop either wire connected or at fault with Active will trip the RCD. Pretty well all home earths are a metal stake into the ground, not the water piping.

Where there might be a problem in domestic wiring is if it is very old wiring or not done to Standards or if an older house previously owned by another that has done some "unauthorised" modifications.

i.e. Many years ago I did the electrical trades certificate, but never worked as a sparky, so never held a license. I keep my electrical work to low voltage DC and although capable, pay a licensed sparky to do the other stuff. I have on a couple of occasions done the work, but had it checked with a compliance certificate issued by a licensed sparky. (Mates Rates etc)

FYI and in simple terms - If you draw a hypothetical line on the outside of a power point, light fitting or mains power board, you need a license for anything inside that line. Items you plug in or extension leads no license is needed, even so, if you don't know how, DON'T.

RCDs should be tested a couple of times a year in my opinion, they are after all, an electrically operated mechanical device.

 

[Moneybox]

Ok guys you've convinced me. There's good value in having the place checked out but Booney might have given me the best option. I trust my own work more than the average tradesman regardless of his profession. It's not that there are not good tradesmen, of course there are but you never know until some time after the job is done if you got a good one.

I had a problem a few weeks back where the tenant in a house in Geraldton had a roof leak over the laundry. Fortunately it was leaking onto ceramic tiles but there was a good chance the ceiling would soon be destroyed. I did the Google thing and found the best plumber, five stars and lots of good feedback. He was good, arrived in no time at all and changed out a couple of roof tiles. While he was at it I had him go over the road and clean the drains on vacant the duplex pair. I'd had problems there earlier but pulled a big long chunk of grass out of the exterior vent and sorted that out.

Anyhow the outcome was good. The roof leak was fixed and the report from over the road came back as all drains free and clear. The total of the bill was less than the cost of fuel for me to drive there and back.

I turned up there last week and walked out the back. There was one of those little 5" plastic exterior vents lying on the ground right beside the vertical union it was meant to be covering. I just had to slip it back in the hole and give it a slight turn to the right to lock it in. I wasn't surprised just disappointed. I don't know how people can put up with this type of thing over and over again :argh:

 

[madtuna]

While a Tag & Test won't stop you chopping through your lead, it'll sure as hell remove some leads and power tools from a job site that should never have seen the light of day.

 

[LONEWOLF]

I have been a Safety Officer and First Aider for quite a few of Australia's biggest Air-Con Companies in QLD and NSW. I have seen many times, people including Work mates who have suffered Shocks from Faulty Equipment... Testing and Tagging SAVES LIVES.. Yes it is a pain but a pain that Should be taken very Seriously AND IT IS ..
There are SEVERE Penalties for falsely tagging an electrical device.... That includes Gaol time for employers of the Injured person.. Even Safety Reps are 'open' to these penalties ... There are heaps of on-site Deaths that you never hear about...

I personally have had several near misses as one should playing with sharp metal, elect leads and power tools every day and one resulted in a Hospital Visit for 2 Days... I have also seen Fellas that have been burnt to Death from an Electrical Shock... Blackened and charred... Not a pretty sight... And a very sad Preventable one...

Me?, I never want to go through it again... The pain I suffered during my 2 weeks off was agony.. It took me 3 days to be able to get out of bed... And Mine was only a small boot like yours MB...

I started My working life as an Apprentice Electrician... Only did 16 months as I saw 2 guys get fatal shocks.. So no more playing with something that you cant see for Me...
I can see your 'Ideas' of how and why things work MB and your 'curiosity', I know with what you are doing in your 'Testing' methods will only have One Sad outcome...

Surely Someone else near you needs a sparky to do some work as well... if you get a few together it will be well worth it for a sparky to travel out there, and perform your Testing for You...

Please get a sparky out there... Something is not right... Perhaps your Power point you plugged into is NOT on the RCD Circuit... That was the reason I got Zapped... And that was on a Major Site, here on the Gold Coast in 2008...

I have even rented a house where all house circuits were NOT Connected to the RCD's... only the large shed... An Electrician nearly Died when he grabbed bare wires after he thought he had Disabled the Circuit that he was working on...

There are Millions of Homes in Australia that have 'Electrical Faults' in them, just waiting to start a Fire or worse, Kill some-one...

LW...

 

[Solid Luck]

Can you imagine me calling an electrician to Cue from the nearest town Meekatharra just 115km away and asking to have my home electrics checked out. I might get lucky and actually get onto somebody who cares enough to tag my job on to somebody else's but the best chance is that we'd both be charged 3 hours travel for a job that could likely be knocked off in under an hour. Even that mightn't be too bad if you actually got a decent tradesman but I know the odds

Depends how much you value your life mate.

 

[deepblue]

Just a point to remember MB is that the sparkie would have tested the home as the test required but where you where working is not under the tested area. When I was working over in the west we found that the ground was very dry and earthing presented all kinds of problems. I some situations we could not get the low reading required for the test and had to put earth grids in so that protection circuits could work. This would involve running a copper bare earth wire back and forth in a trench for sometimes 50 metres just to get a good conductivity reading. What I'm trying to say is that the distance between where you were grinding and the earth stake may have been to great. The conductivity through the ground could have been to high for the protection circuit to work. A good sparkie would be able to test the conductivity of the ground from the earth stake with a megger.
Hope this helps
Cheers DB
A electrician for 50 years contracting to Mining and Construction.