Thread: Electrics & Plumbing - What Am I Allowed To Do?

Originally Posted by mick101

Dont worry about not understanding how a basic household MEN system works & its relation to keeping your family alive...its that pesky red wire thats the only one that you think kills anyway 'eh ? ...you need to save money, thats all thats important.

I've got a fairly good understanding of the MEN system. I'm just asking you to substantiate your claim in your scenario. It's not too much to ask, is it?

Originally Posted by chrisp

I've got a fairly good understanding of the MEN system.

No you dont...you just proved it in writting mate...not having a chop at you but if you dont know what im talking about (any 1st apprentice year house sparky should) then you are the perfect example of why we are so flamin' ???? scared of any industry deregulation.

Thats really it this time...heat the pizza up for someone else.

Mick, you seem to be spending a lot of time NOT answering the question .
I also would be interested in the answer. What's wrong with educating the electrically inept? Do you think the answer will some how encourage us to rewire our entire house?

Mick,

The only reason I keep replying to this thread is that I think what you have posted is alarmist.

If you can explain a scenario that can end up with the results stated then please do.

If not, please retract the alarmist comment.

I'm out of here for now - I've got to go.

Have a look at page four of this document, issued by Workplace Standards Tasmania.

http://www.wst.tas.gov.au/electricit...ulletin4-6.pdf

Edit: Page one explains a bit too!

Originally Posted by Tas_Dean

Have a look at page four of this document, issued by Workplace Standards Tasmania.

http://www.wst.tas.gov.au/electricit...ulletin4-6.pdf

Edit: Page one explains a bit too!

Yep, I understand that loosing the Earth-Neutral bond bit and how it results in tinkles.

But, walk me through the scenario:

1. The kid has a tooth brush, let's make it electric,
2. the tap is turned on.
3. one hand on the tooth brush, or brush in their mouth,
4. other hand in the water...

and explain how "you can find your kid dead beside the bathroom sink with the bloody toothbrush still in their hand" because of a neutral problem.

chrisp, here's an answer.

assume the house doesn't have an rcd [many still don't] and that the toothbrush is a plugin, not battery powered. if the neutral wasn't connected, the only possible return path for current would be through any exposed metal of the toothbrush [unlikely that the brush is either metallic or plugin]. the metal is hence inside the kids mouth, right near the brain. it's wet. so there would be a reasonable current path into the kids mouth. the path continues down the arm to the tap or water. the water going down the drain, or the pipe will be bonded to earth at somepoint. this completes the current path.

the kid now receives a belt through the mouth, possibly causing brain damage. this overload will only stop if the current racing through his body [and the rest of the circuit] exceeds the rating of the breaker or fuses. there is a longer time delay for fuses too. this kid has now recieved a fair amperage to his brain. also through his chest, lungs and heart. there will be sever burns to his hands and mouth.

this faulty neutral could have been anywhere within the circuit, swithboard or even the toothbrush itself.

even if there was an rcd, the kid will still receive a belt of 30mA, which while not considered enough to normally kill an adult [it's around 300mA i think, severe injuries would still occur] the situation [a kid in wet circumstances getting a belt to the head and chest] could still cause death.

does that answer your question?

chrisp, you probably know my feelings enough on the bulk of the topic so i won't delve into that, there are pages enough of my ramblings.

here's your answer ( one of many scenarios). PS im a plumber.

In a house it is entirely possible that electric current through earth leakage can travel down through water pipes (and sewer aswell if is lead or gav.)

This current is present in all the water pipes when there is a earth leakage present and the house - as in all old houses and some new ones- is earthed through the water.

Why- sparkys used to earth all houses through the water because the water would eventually go to ground ( street mains).
Now they are supposed to use an earth stake or something.

If there is an earth problem in your house, your power board may not trip.

If you touch the taps (connected to water supply and earth) you may be an easier path to ground than the rest of the water supply, you will become the earth for your house, you will get shocked.

As i understand it is difficult to test for an earth that is still going to ground, but in a way other than intended. The end result is the same.

What is worse than this is if the current goes through you and then back to the electrical system.
- why - because then there is no earth fault and the rcd wont trip.

If you don't follow this then i suggest the most you should do is lick a 9volt battery to see if its charged.Apparently that will hurt you so dont really do it.

Originally Posted by chrisp

Yep, I understand that loosing the Earth-Neutral bond bit and how it results in tinkles.

But, walk me through the scenario:

1. The kid has a tooth brush, let's make it electric,
2. the tap is turned on.
3. one hand on the tooth brush, or brush in their mouth,
4. other hand in the water...

and explain how "you can find your kid dead beside the bathroom sink with the bloody toothbrush still in their hand" because of a neutral problem.

I suspect the kid would only get to level 2, and that would be with an ordinary plastic Oral B!

As for tinkles - tinkles may sometimes be a warning, but in this scenario, at its worst, the kid would still be hanging on to the tap with his/her teeth chattering. The path, for those interested, has nothing to do with the toothbrush but is a circuit from the metallic tap, through the body to earth - in this case, probably bare feet and a damp floor. Carpet might slow it down somewhat and result in the tingle.

I've spent all afternoon reading this thread from the beginning. I'm a renovator and lay much of my own wiring but generally get a sparky to wire up fittings etc.

I've just looked at the wiring diagramme on the tas.gov document -- UM -- Surely running an earth wire to a water pipe is incredibly stupid ???!!!!???

A few houses ago (3 years ago) I found such an earth connection and as I was going to get a new box put in I got the sparky to remove the connection. He didnt seem one bit surprised that the earth was running through the water pipe.

DD

I was trying to think of cases involving tingles - how's this:

Electrician who worked for the Hydro Electric Commission in Tas in the '80s, walking into a substation yard was feeling the tingles in his feet (through his boots). Turned around and walked out, reported it. His supervisor thought he was skiving, so came for a look and also felt the tingle - turned out to be a fairly major fault and defective earth protection. Very lucky boys, the substation was carrying 110 000 volts (or 220 000, can't recall, but it was a main substation dealing with transmission from the Hydro dam down into Hobart).

Originally Posted by Dirty Doogie

I've spent all afternoon reading this thread from the beginning. I'm a renovator and lay much of my own wiring but generally get a sparky to wire up fittings etc.

I've just looked at the wiring diagramme on the tas.gov document -- UM -- Surely running an earth wire to a water pipe is incredibly stupid ???!!!!???

A few houses ago (3 years ago) I found such an earth connection and as I was going to get a new box put in I got the sparky to remove the connection. He didnt seem one bit surprised that the earth was running through the water pipe.

DD

Incredibly smart - an earth bond is required on the water pipe and forms part of the earth protection (MEN system). Basically, the earth system protects you from the scenarios above - ie live tapware, sinks etc. The idea is that fault current passes to earth and trips the circuit protection. If you don't have a good protection system, then the current will pass through you to earth.

Crisp.

As a master plumber, gastfitter and builder in S.A. i recieve a magazine published by the OTR called regulation roundup.

Here is a PDF file of the latest issue
http://www.technicalregulator.sa.gov...RR19_Apr07.pdf

Look at page 4, and page 6 for the technical explaination of what can happen. Notice on page four the there doesn't even need to be an earth fault for the shock to occur, too much resistance can make it happen along with other things.

Eg you do your own conversion from one light globe to 4 or 6 downlights- the draw on the power is roughly the same but the resistance is multiplied by 6 or more due to the voltage drops and so forth ( remember im not a sparky). The DIY peanut thinks he's ok coz he's using less power but in fact he's designing a system that can easily fail in the newish ( 60's-70's)super dooper mens system of earthing.

Hope this acces to new and correct info doesn't make you over confident.
Look on page 6 as to how many people are shocked in one month by tap ware or other items connected to water supply, or roller shutters or T.V sets or what ever.

Ps : just incase your curious : if you lick a 9 volt battery- it tastes funny, dont do it.

Hi Cauterize,

Do they still earth to waterpipes on new builds?

DD