Earth Pins on Power Tools

[Barry_White]

Our's is not to reason why. Our's is but to do or die.

[Bleedin Thumb]

Are you sure that it is a requirement to have earthed powertools on site.

I know there is a requirment for fully molded plugs that have to be trip tested and tagged monthly.. and I dont recall ever having a 2 pin tool knocked back..... is this a requirement of AS/NZ 3012 or a State WorkCover requirement?

It seems a bit silly when around 50% (my guess) of tools are double insulated.

Because of the reqirement of the fully molded plug my cords are getting shorter

[rat52]

There is no requirement for double insulated tools to be earthed on building sites.

The RCD will not trip until it detects a leakage to earth thru your body or if you cut thru a extension chord with an earth wire

This sounds deadly but the current trips out in less than a 30th of one cycle and our current runs at 50 cycles per second. You do the math. You don't even feel it.

Always check you house RCD at least once ever 6 mths

Remember also that your light circuit may not be RCD protected

[Burnsy]

Are you sure that it is a requirement to have earthed powertools on site.

I know there is a requirment for fully molded plugs that have to be trip tested and tagged monthly.. and I dont recall ever having a 2 pin tool knocked back..... is this a requirement of AS/NZ 3012 or a State WorkCover requirement?

It seems a bit silly when around 50% (my guess) of tools are double insulated.

Because of the reqirement of the fully molded plug my cords are getting shorter

I am not 100% sure you know how sleepy you get in those Blue Card training courses - now don't get me started on that. It may have been extension cords that required earth, not tools. I know there was allot of talk about how many extension cords get damaged by being run over or having the bricks and the like dropped onto them.

I just found it strange when I cut the cord and found no earth wire but three pins and thought it was in a way "false advertising", never mind, it has a short cord now that won't reach the blade and the extension cord certainly is earthed! It makes sense now though given that some of the old power points required three pins.

[Binary]

50 cycles per second = 20ms, yeah thats cool. 30th of 20ms, 0.66ms?? How many RCD's have you tested that trip that fast? I have never seen one even close to that

Remember everyone - RCD's improve/increase saftey by tripping when there is a eath fault. They do NOT limit the fault current to 30ma, you can still DIE. Most the time we are not barefoot in wet ground are we?

Just found this some people may be interested in:
http://en.wikipedia.org/wiki/Electric_shock

This sounds deadly but the current trips out in less than a 30th of one cycle and our current runs at 50 cycles per second. You do the math. You don't even feel it.

[wheelinround]

Read in SMH this morning
http://www.smh.com.au/news/national/...833598179.html
Tests fail to pick up dangerous electric products


Kelly Burke and Arjun Ramachandran
July 12, 2007



SUBSTANDARD imported electrical goods are slipping through the testing net and threatening the safety of Australians, according to manufacturers.
In the past four months, one-third of the more than 60 recalled products have been cheap imported electrical or electronic goods, data recorded by the Competition and Consumer Commission shows. The products range from faulty power adaptors putting users at risk of electrocution, to computer battery packs prone to overheating and igniting.
In one of the most recent recalls, issued nationally late last month, almost 70,000 power sockets were found to be so poorly made that when a power plug was inserted or removed, the protecting plate fell away exposing the live terminals in the socket.
The commission does not record the country of origin of recalled products and many companies the Herald contacted either refused to reveal the country of origin of the recalled product, or were unable to be contacted. But of those companies which supplied the Herald with information, more than half said the faulty product or part had been imported from China.
Bryan Douglas, the deputy chief executive of the Electrical and Electronic Manufacturers Association, said the industry had become increasingly concerned about the poor level of monitoring in relation to the quality and safety of some products imported from China.
Mr Douglas cited recent examples such as portable lights with faulty earthing, and miniature circuit breakers and safety switches which failed to work.
"There is a flood of electrical and electronic goods coming into the country," he said. "Some of it is patently unsafe but we do not have enough mechanisms in place to deal with the unsafe products."
Mr Douglas said there were even problems with some Chinese products subject to mandatory certification under the "inherently dangerous" category, because the certification logos and labels were counterfeit.
The Competition and Consumer Commission collates the details of product recalls, under Australian regulations.
However, each state, working with the Customs Service, is responsible for monitoring the safety of imported manufactured goods and supervising product recalls.
Gunther Theisz, the president of the Electrical Compliance Testing Association, said there was evidence to suggest inferior products were being dumped on the Australian market because compliance regulations such as mandatory on-site factory inspections did not exist here, whereas such regulations were strictly policed in the US and the European Union.
Mr Theisz agreed with the Electrical and Electronic Manufacturers Association, saying a lack of resources meant electrical safety regulators felt that they were unable to monitor thoroughly all potentially dangerous products entering the country.
"Very often, the regulators are just relying on competitors to dob each other in," he said.

[pedro the swift]

Double insulated tools are not required to be "earthed". In fact some are marked "do not earth".
Three pin plugs on such tools are a historical fact not a operational necessity.
RCD devices will protect against active to earth faults and trip quickly enough to protect against shock but will not protect against getting caught across active to neutral. That will surely result in injury or worse since the only protection is the fuse/breaker. This only protects against current overload (16 to 20 amps or thereabouts).
Extension leads need an earth pin since there is no control over what appliance/tool will be connected to them.
They also need to be regularly tested, as with tools.

[malb]

Double earthed items are not be fitted with an earthed lead because in the event of a problem within the double earthed enclosure, an earth lead provides an exit path for electricity, negating the benefit of double earthing.

As previously mentioned, many double earthed tools have a two core cable fitted with a three pin plug. In this instance the "earth" pin is a dummy to activate shutters on power boards. When power boards were first available in Aus, they were the 4way individually switched type, allowing users to isolate equipment before unplugging. The next generation dumped the switches, and had a spring loaded shutter that obstructed the active and neutral ports until an earth pin pushed the shutter aside as the plug was connected. Now we seem to have power board without switches or shutters.

Your RCD (safety switch) did not disconnect because you did not provide an alternate earth return path for the current. Had you touched the active while providing an earth path through another tool, a metal fixture or bare feet on a damp floor, the RCD would have disconnected power almost immediately. You most likely would have wondered why the lights went out and the other machinery stopped, rather than 'whats that odd tingling sensation'.

[Burnsy]

Thanks for the responses guys, it makes sense now.