Installing cooktop - do I need an electrician - and if so why?

[silentC]

I got this from wikipedia (Electric shock):

It is believed that human lethality is most common with AC current at 100-250 volts, as lower voltages can fail to overcome body resistance while with higher voltages the victim's muscular contractions are often severe enough to cause them to recoil (although there will be considerable burn damage). However, death has occurred from supplies as low as 32 volts.

[Ashore]

rrich
Thank god he didn't say it happened a fortnight ago or you would have realy been lost

As to the electrical tape , it is only used to cover the BP ( Screwed Connector) not to join wires , this tape can also be a good indication of a hot joint as it will hardens and crack from the heat.
You refer to wire nuts if these are the twist on type then they won't pass some Australian rules
Earth wires have to be joined by open ended connectors and held by two screws etc

Silent is correct as to the amperage , and DC is more dangerous than AC, its just that theres not as much around.

[chrisp]

While I agree with the comment "if you have to ask them you shouldn't be doing it", I think the electrical regulations in Australia are too tight - and I suspect that it isn't purely due to safety concerns. My view is that if you can demonstrate the required knowledge and practical skills you should be able to obtain a wiring licence.

In my case I'm a tertiary qualified electrical engineer (and I'm employed as a design engineer). My knowledge of electrical theory goes beyond that covered in AS3000 (I work in research and I have explain technical electrical matters to fully qualified electricians). I'm reasonably competent with hand tools and can soon strip and join wires (I routinely make connections that are used up to 1000A in my work). I also have worked on high voltage equipment. Can I obtain a wiring licence to do my own work in Victoria? Damn near impossible!

I have spoken to the Office of the Chief Electrical Inspector (OCEI) some years ago and the regulations seem to be a bit of a Catch-22. (Details are bit vague now, but it went something like this.) I could, theoretically, go to a TAFE collage and do a course on sitting the wiring rules exam, but I would also need 80 hours practical experience to obtain the "Occupiers Licence" (which is what I was enquiring about). No problem I thought - I know an A-grade electrician and I could easily arrange to work along side him for the required time. But according to the OCEI, to work with the electrician I would first need a "supervised workers licence". How do I one, do another TAFE course, but I would have to be apprenticed to an electrician to be able to do that course. Bottom line was that to obtain a wiring licence I'd have to effectively do a 4 year apprenticeship.

Are the regulations intended to keep us safe or are they intended to maintain a closed shop?

(Ahhh, that feels better - good to get that off my chest )

Chris

[silentC]

DC is more dangerous than AC

I was reading a bit about that in Wikipedia. Because it doesn't cycle, DC 'grabs' hold of you and wont let go, so you can't let go of whatever it is that is electrocuting you. With AC, you get a chance to let go. The problem with AC is that the alternating current messes with your heart's pacemaker and so most electrocution deaths are from fibrillation and subsequent cardiac arrest.

I went to school with a guy who was walking home one day and he casually reached up and grabbed a cable as he walked under it. Turned out it was a high tension cable that had come down in a storm. He couldn't let go and his mates thought he was mucking about until the smoke started coming out his ears :eek: It burned off his left arm to just below the elbow and left huge burns on his back and the tops of his feet. Very luck to have survived.

[silentC]

are they intended to maintain a closed shop

I think we all know the answer to that

[Markw]

a leco with a multimeter has reason and knowledge to work on live electricals - a householder doesnt

A point of note here:

Under Regulation 2000 OH&S No electrician is permitted to work on a live installation. Special dispensation is granted to electrical workers employed by distribution authorities such as EnergyAustralia, Intergral Energy, Country Energy etc to work live low voltage (below 600V). Can't have the power company turning off the Sydney CBD just to replace a blown wire fuse

Silent

With regard to electrocution and Wikopedia I have a hard time believing that a supply of 32v is capable of causing injury. I have spent many many hours working on 36v and 48v forklifts without sustaining even a tingle and these units have the capacity of huge amperage from the battery system. Maybe under special circumstances ie had pacemaker, standing upside down in bucket of water to increase conductivety and subsquently drowned!

No you must first have sufficient energy (joules) to electrocute and the voltage must overcome resistance. The amperage at a high enough voltage to cause defibrillation can be measured in milliamps - Think of modern day automotive high voltage systems (spark plug leads), these can and have cause defib. As to household systems, all RCDs are set to activate at lower than 100mA which can still provide a nasty tingle up the arm - just ask my builder, he found a loose wire in a wall cavity with his bare knuckle - the wire had been cut off and hanging in space by the previous owner who mustn't have liked the old GPO position.

[Markw]

With AC, you get a chance to let go. The problem with AC is that the alternating current messes with your heart's pacemaker and so most electrocution deaths are from fibrillation and subsequent cardiac arrest.

You DON'T get a chance to let go. At 50 cycles per second your muscle will just contract and not extend/contract at 50 times each second; all the time while the electricity is charring the point of entry and the point of exit - usually your hands and feet respectively. You might note that by charring, the flesh is carburised and thus making an even better conductor.

At least with high voltage you will probably be blown clear by the blast. All you have to contend with is the 2000 degree C plasma gases and blast debris which will incinerate your lungs and throat.

I've commissioned and viewed low voltage arc testing
415V - 25kA - what our people work with daily and it's really scarey. Don't ever want to be a conductor.

[pharmaboy2]

Apology not accepted.:mad: poor tiling never killed anyone

I have no problems with people such as yourself going for it with domestic wiring but don't ring a sparky when it doesn't work OR you don't know how to do it so can't finish it OR you electrocute someone OR your house burns down. You will deservedly get a short answer. If the guys you have used in the past are crap then tarring the whole trade with the same brush is obviously easier for you than dealing with the issues & people at the time.

Well, adding another apology obviously wont help if the first didnt. Possibly, more info will help (though it may not) - the phone call was on a sunday (try getting a trade on a sunday!) after the flappin wires fell out of a triple switched light, while changing over a cover plate (2 architrave switches to one) - simple answer was like getting blood from a stone from this relo with a 10 minute lecture - so not all are maybe as understanding as some.

"by the guys we used" was an attempt to make clear that I was speaking "in my personal experience" not generally. There are only 2 trades we are forced to use - sparky's and plumbers. Anyone else stuffs up and the builder can fix it on the spot (within reason) except for those 2 - rest assured, if you were waiting on your final 20k payment because someone mucked up and you cant get them back to the job site inside of 6 weeks - you'd be too!

chrisp, - have 2 electrical engineers as friends, its a pretty strange world at times - one says when going round plant, he feels like a King with his own "food tester" LOL! - design it, just dont touch it!

[Auld Bassoon]

Letting any mug do his own wiring is a dumb idea. .

I was once chartered to take a sixty five footer sloop-rigged yacht from Durban to Cape Town, with two other crew; the voyage (about +/- 4 days) was also to include 5 or 6 'guests' of the owner.

Being mindful of the state of some yachts, I and the bosun gave the boat a thorough examination about a week before we were due to sail. This included not just the hull, spars, standing & running rigging, but all the navigation, safety equipment, pumps, water systems, mechanicals - and electricals.

Like most larger yachts she had 24v lighting and domestic, but she also had an Onan 6KvA genset.

On opening up all of the circuit access ports we found that all of the wiring was black, and all the same size. :eek: Not only that, but a bank of 8 very large lead-acid batteries, with open copper terminal interlinks were sitting just under (I do mean 'just' - i.e. about 20mm) the fabricated steel platform that the genset was bolted to, and that the batteries were unsecured vertically. Clearly someone had forgotten that boats to move up and down, not just fore & aft....

On querying the owner, he 'fessed-up that he had "refurbished" the boat himself - with clearly not a clue (or brain cell) being used anywhere.

Needless to say we declined the charter

Auld Bassoon - Thread Pirate

[Pulpo]

I wired up a small shack using DC from solar and battery bank.

I knew little to nothing on the subject but the shop that supplied just about everything was most helpful.

They also stated that no requirement, when installing DC, for a sparkie.

Still do not know why there should be any minimum time limits for doing any apprenticeship.

Pulpo

[Markw]

I was once chartered to take a sixty five footer sloop-rigged yacht - all of the wiring was black, and all the same size. :eek:

This reminds me of the very early dodge scout vans and some of the early International Harvester Acco 1940's. They were both wired in a pasty yellow colour :confused: . Admittedly there were some other colours with the IH Acco but mostly yellow. At least the wires had numbers on them which you could sort of follow. Still its a very dumb way to identify different circuits and DC circuits burn really well if crossed.

[Ashore]

I think the electrical regulations in Australia are too tight - and I suspect that it isn't purely due to safety concerns.

Must agree 100% , on a ship I am qualified to handle all electrical work , from 3.3KV to 10 volt and all in between, have worked on breakers and power generation systems big enough to power a town .
Plus the electronics , all the accomodation wireing , dealt with dc power generation and motors, approved as a lecturer regarding ships electrics, and yet am not allowed to change a three pin plug at home,
Some of the so called qualified people I have seen work and others I have had to employ I would have sacked at sea
It's a closed shop like plumbing but I think there should be a weeks course type thing to allow you to gain a limited licence to undertake certain limited work on your own Home.

[silentC]

With regard to electrocution and Wikopedia I have a hard time believing that a supply of 32v is capable of causing injury.

You should go and update it then if it's wrong: http://en.wikipedia.org/wiki/Electrocution

[Exador]

They also stated that no requirement, when installing DC, for a sparkie.

Pulpo

There is no requirement to be licensed to work on ELV, which is <50V. It doesn't matter whether it is AC or DC and I have worked on some solar installations in which the battery bank was wired as 240V, simply to minimise transmission losses. Of course, as I'm not a sparky, I must have been imagining it, I reckon .

Still do not know why there should be any minimum time limits for doing any apprenticeship.
Pulpo

I can see a need for it, simply because the average pimply-faced youth needs to have everything drummed in several times before it even sinks in that a rule exists and then a few dozen more times to recognise when it applies. In the case of those with prior experience, such as our electrical gingerbeer friends, or a TA with experience, it is a bit stupid and largely intended as a measure to protect those already in the business from open competition. In my own case I feel quite competent to cable and connect my own home / business in accordance with AS3000 because of other background that I have, although I've never worked in the field directly.

[lnt9000]

A point of note here:

No you must first have sufficient energy (joules) to electrocute and the voltage must overcome resistance. The amperage at a high enough voltage to cause defibrillation can be measured in milliamps - Think of modern day automotive high voltage systems (spark plug leads), these can and have cause defib. As to household systems, all RCDs are set to activate at lower than 100mA which can still provide a nasty tingle up the arm - just ask my builder, he found a loose wire in a wall cavity with his bare knuckle - the wire had been cut off and hanging in space by the previous owner who mustn't have liked the old GPO position.

I think your builder is a very lucky man, one of the first things I learnt when learning electronics was: (don't quote me on the figures but they are close)
1 microamp = tingle, 50 microamp will throw you a few meters away, 1 milliamp and you wont see the sun rise, this is all pertaining to 240volt, I think the potential was there but the duration was too short.

Here is an extract from an article published about 3 years ago, to back up my previous post.

Further to my previous letters, I spent almost the whole of March in New Zealand and I had a very informative and productive meeting with a senior official of the Energy Safety Service within the Ministry of Economic Development. Here is a brief summary of some of the things I discovered.

(1). In a comparative study of international annual electrical fatality statistics done by the New Zealand Energy Safety Serv&ice, Queensland consistently had the highest levels of electrical fatalities in Australia. Much more interestingly, Australia had higher levels of electrical fatalities than any other country studied, with the exception of Northern Ireland.

This New Zealand study confirmed the results of a similar study done by the German government, so the results are corrobo&rated. The country with the lowest electrical fatalities (by a huge margin, varying from year to year between 0.5 and less than 0.1 deaths per million of population), is The Netherlands, and this is one of the many countries that allow householder DIY wiring). Australia has the second highest levels of annual elec&trical fatalities (varying between 2.5 and 4 deaths per million of population).

Now Northern Ireland is an extremely turbulent society. Yet by the German and New Zealand comparative studies, Northern Ireland is the only country with higher levels of electrical fatalities than Australia! The Australian statistics reflect the gross irresponsibility of the great Aussie tradition of allowing powerful vested interest groups to "regulate" themselves.

(2). Prior to 1992, it was illegal for any electrician in New Zealand to explain any technical aspect of electrical wiring to anyone who was not a trainee electrician, or not otherwise li&censed to do "electrical work". This prohibition was seen as a serious impediment to the new electrical safety regime and was eliminated in the 1992 changes to the NZ electrical safety re&gime. (It appears there is no similar prohibition in the current Queensland legislation).

(3). Anyone can assist an electrician to do electrical work in New Zealand, without the electrician having to look over that person’s shoulder. So for instance, after an electrician has agreed to supervise your work, you could bolt up the control panel and connect the house cables to it on your own and the electrician would just do a quick check on your work when it is finished.

(4). Only completely new work and extensions, etc, are required to be inspected in New Zealand. You can replace and relocate wiring, power points, switches, etc, without notifying the au&thorities as long as cable lengths are not altered. The exception is wiring in metal conduit. New Zealanders are not allowed to work on systems run through the old metal conduit systems. Howev&er, they can remove all the metal conduit and then rewire the house with modern cable and components.

(5). Interestingly, the overwhelming majority of additions to houses in New Zealand are done on an owner-builder basis, there&fore much of New Zealand DIY electrical work is the wiring asso&ciated with such additions. Of course, entire houses are built by owner-builders in New Zealand and in these cases almost all the wiring is done by the owner.

(6). Specially certified "inspectors" do all required inspec&tions, not ordinary electricians. The "inspectors" are liable for the quality of the inspection but not for the quality of the work. If and when the work appears to be particularly shoddy or unsafe the inspector can refuse to do the inspection.

New Zealanders are advised by their Energy Safety Service to secure the services of an "inspector" before they begin their DIY electrical installation work. These "inspectors" are private operators, not government employees, and of course, the homeowner has to pay for the inspection service. These inspectors advise the homeowner on the technical aspects of the installation if they feel such advice is needed.

(7). The senior NZ Energy Safety Service official I spoke to made it clear to me that homeowner DIY wiring will not change in New Zealand as a result of all the ongoing reviews, which are now largely concerned with the health and safety of electrical work&ers in industry. The attitude of the New Zealand authorities is that there is no danger whatsoever when DIY electrical work is done according to law.

(8). The New Zealand Energy Safety Service has the attitude that old cables, switches, power points and other fittings need to be able to be replaced at low cost. They believe the sorts of dan&gerous situations where people continue to use cable and fittings of questionable serviceability are dramatically reduced by allow&ing householders to replace these items themselves.

(9). Before 1992, electrical engineers and associate engineers in NZ were authorized to do all "electrical work". This has now changed for new graduates though all licenses current in 1992 continue. Recently graduated engineers and associate engineers can apply for electrical contractor licenses after fulfilling appropriate (minimal) training.

In Australia, there is no way to avoid the four-year ap&prenticeship. Let’s face it, which electrical contracting busi&ness would take on an adult trainee on adult wages when they can get a teenage apprentice at slave labour rates?

So effectively, there is no practical path to an electrical contractor’s license for engineers and associate engineers in Australia.

(10). When New Zealand decided to reassess its electrical safety regime they sent an official overseas to study the electrical safety regimes in other countries, including the United Kingdom and USA systems. In the National Competition Policy review of electrical safety in Australia, there is no requirement whatsoev&er to even look at "world’s best practice".

(11). In the United Kingdom, electrical licensing is relatively weak and electrical standards compliance is primarily enforced through insurance. The UK, which has long had householder DIY wiring, has annual electrical fatality levels below 1.0 per million of population. Compare that to the Australian figures!

My extensive interactions with New Zealanders were such that I can wholeheartedly confirm the comments of I. Morrison in the January 2001 Mailbag. New Zealand really is a much kinder, fairer society that is much more protective of civil liberties than we are in Australia. So please, wake up Australia!

Well after that what can you say?, the proof is in the pudding!!!