Adding a new power circuit

[thatirwinfella]

I had no intention of being rude or of questioning your intelligence. the implication of what I was saying was that if you have to ask for cable sizes or the best method to do the job then you are obviously not an electrician.

A tafe course with some basic circuitry [certificate I perhaps?] is definately not enough for you to rewire a house, particularly anything involving switchboards. I have done a similar course before starting an apprenticeship and the one i did was not advanced enough for anyone to think about doing osmething to what you have proposed. Just because you thought a course was easy does not imply that rewiring a house will be.

Your choice of cable sizes is also questionable, but forgiving if you have misplaced AS3008. 10mm is overkill. 6mm is overkill. If it's just a laundry 4mm is likely overkill... although you could just have a rather large washing machine for all I know. There you go, thats some advice.

You will probably have a hard time getting an electrician to sign off on another persons work even if they test it. Thats just something I've come across.

I understand people would not want to give home renovators detailed electrical information as they might not understand the basic principles of electricity.

I agree with what boban and Sturdee have said, if you ask an electrical question you're likely to get a poor response due to the safety aspects and legality.

[Pulse]

Hardy, I like your second post, because I think that people with the knowledge should be allowed to do wiring in their own home with certain regulations and supervision. I also think it would be safer than having houses full of split steel conduit and cotton insulated wires.

You have the right standards to do the job safely. I've found AS 3018 for domestic installations a bit more useful than AS 3000 since it only gives you the details you need for that sore of installation.

I'd be happy to help you with any other questions. People need to know that their information is being understood and applied safely, which given your background would be. Boban's point about us not knowing where you were coming from is where it's at.

Cheers
Pulse

[Metal Head]

"I think withholding knowledge on the basis that someone will harm themselves as a result of that knowledge is paternalistic and at times arrogant"

Surely it is better to give that person the knowledge so they see that the job is hard and then leave the decision up to them....

..knowledge is power...
power is freedom...

Cheers
Pulse

Hi Pulse,

Have you ever heard of the saying "a little bit of knowledge can be dangerous"?. With a lot of trades I would agree with you that people should (or could) pass on their knowledge here but ELECTRICITY NO. Especially when we are talking about the amount of wiring to be done in this case. As was suggest previously, he should get the advice off the electrician who is going to to "sign off" the job.

I read the magazine that is sent out by energy safe and it is sad to see how many lifes have been lost because they had little knowledge of what they were doing. One such case was highlighted in a thread recently by me, where a young lad of 16 was electrocuted. This happened as a result of only taking globes out of holders in a car yard.

Regards
David
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[echnidna]

I don't see why you need to remove bricks.

Drill a hole through the brickwork say an inch or so. Any size will do as long as the hole can be covered by the switch and mounting block.

Immediately above the hole drop a stringleline with a fishing sinker down the cavity.

Fish the stringline out with a piece of wire with a hook on the end.

Tie the stringline to the new cable and pull the cable through the cavity.
You'll probably need someone to feed the cable while you pull the stringline.

[journeyman Mick]

Hardy,
just in case you haven't already, it would be wise to talk to your sparky first and run what you want to do past him first (ie: you fit, he signs off on work). I've done the same in the past as I've got some sparky mates, but you may find it difficult to get someone to sign off on the work if you just present them with the finished job.

Mick

[Strungout]

Why did I do a 4 year Electrical apprenticship.??

I Could have saved myself a few years doing the courses Hardy did.

[echnidna]

Why did I do a 4 year Electrical apprenticship.??

I Could have saved myself a few years doing the courses Hardy did.

The theory is the easy part.
Regulations can confuse very competent electronics people.
And there is the practical experience of an apprenticeship

Thats why!!

[Pulse]

I found an interesting article about DIY wiring in the US:

Even considering the issue of safety offers more questions than answers with regards to how do-it-yourselfing has become such a contentious subject. It seems that every electrician and inspector — including those interviewed for this story — has encountered at least one homemade wiring job that would bolster the case for outlawing DIY electrical work altogether. Yet almost all of that anecdotal evidence comes with a happy ending that involves fixing the problem and averting disaster. Rarely, if ever, do you hear, “If only we'd gotten there a day earlier.” The factual evidence offers scarcely more help. In 1999, only 29 of the 170 nationwide electrocution deaths were attributable to household wiring, circuit breakers, or fuses. Bill King, chief engineer for electrical and fire safety for the Consumer Product Safety Commission, will allow that DIY projects gone wrong are responsible for some of those deaths, but the details are sketchy.

No doubt electricity is dangerous but so is a dodgy 4m high deck. For any job, if it is done properly then it is safe. The availability of wiring stuff is testament to the amount of DIY wiring done.

Surely having information to enable this to be carried out safely is better than no information at all?

Nothing like an interesting debate revisited.
Cheers
Pulse

[spartan]

Pulse,
I agree. Australia has one of highest instances of electrical death in first world countries. Interestingly, the US, UK, and New Zuland all over lower instances.

Each of those nations (ok the UK includes more than one country) allows DIY electrical. They have decided that education is better than legislation. As my dad used to say - you can't legislate against stupidity - as soon as you make something idiot proof - they go and build a better idiot...but I digress. I little bit of knowledge can be dangerous - unless it is put into context - by giving people confidence to do something and the knowledge of what is way beyond their capabilities.

It recognises the fact that people will attempt this work, regardless of the law - so far better to ensure that they do it as safely as possible - in New Zuland you can do 4 day electrical safety courses. This instructs people to do basic home electrical work - again nothing touching a switchboard. They teach you about installing lights, powerpoints, fans etc - and scare the #$%@ out of you about safety and the need to stay away from modifying circuits and opening up your switchboard - they also encourage certification by licensed electricians. - So everyone wins.

I think Australian states need to revist this.

We all know many people who have undertaken this kind of work I'm sure so it is very common. Anyone can buy the requisite gear from a hardware store etc.

[felixe]

I came across this extract while researching workplace health and safety for my current employer, written in plain english it clearly covers the law in Qld regarding "DIY" electrical work:

"Thinking of doing your own electrical work? Think again

Every year, Queenslanders are injured while performing electrical work without a licence.
The Electrical Safety Office regularly investigates these cases, and others where unsafe unlicensed work has been carried out.
Queensland’s Electrical Safety Act 2002 is clear on who can carry
out electrical work – qualified, licensed electricians. Anyone else
carrying out electrical work is breaking the law.
The law exists for a simple reason – electricity can be dangerous
and care should be taken with its use. Even if you are a confident
do-it-yourself you should never take risks with electricity.
The Electrical Safety Office recommends that all electrical work be
carried out by a licensed electrical contractor.
Want to find out whether the electrician you have selected is
appropriately qualified? Visit www.dir.qld.gov.au."

The above extract was taken from "Safe" magazine, the May 2006 edition which can be downloaded from the Qld Dept Industrial Relations website. This legislation, the electrical safety act of 2002 only applies to Queensland, however it is clearly stated in plain english where you stand if you carry out any electrical work in Queensland and do not have the appropriate licence.
I am not trying to stir up any past threads, or to question the "ability and knowledge" of other members in completing their own electrical work, but I thought this would help clarify the issue for QLD members.
(If you get caught, the fine will far outweigh the cost to hire a sparky!)

If in doubt, then contact your state department for clarification.

Regards,
Felixe.

[felixe]

What the?

Sorry guys, that was cut and paste, I don't understand why the font size is so large, can't change it in edit - so if a moderator can help out, then much abliged. (oops! - not shouting, honestly!)

[hardy]

Thatirwinfella the power circuit in question is for the laundry, kitchen and one bedroom.

Quote from Ashore
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</TD><TD class=alt1 id=td_post_341173>Would it be easier to get the existing wireing replaced with a 20 amp circuit as you could use the existing cables to pull the new cables at each point.<!-- / sig --></TD></TR><TR><TD class=alt2></TD></TR></TBODY></TABLE>

When wrote 10mm cable i meant for rewiring the existing power circuit for the laundry, kitchen and bedroom and replacing the existing circuit breaker with a 32A. I will have to refer to AS3018 for domestic installations to find the maximum demand allowed on a power circuit.
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I don’t have the statistics for it but I believe electricians have one of the highest fatality rates from electrocution. As an electrician you obviously know the theory and abide by the standards and also have the experience. The only thing i can attribute this to is an electrician completing the same jobs daily and therefore becomes more confident and as a result might make mistakes trying to save time. Whereas I myself understand the rules and standards and will take my time and double check my calculations as I am not as experienced as an electrician.
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Strungout the computer engineering degree I did was a five year degree. I might not have found the tafe courses so easy had I not done my degree. The only difference between computer engineering and electrical engineering is 5 subjects and I completed 4 of these as electives. Electrical wiring was not part of my degree and that’s why I completed by tafe course. Obviously the practical experience obtained as an apprentice is important.

Echnidna thank you for your message and advice.
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Pulse I agree with you and I was planning on referring to AS 3018 for domestic installations. Firstly thank you for your message and advice.

The reason why the16A circuit breaker is tripping is because recently we replaced the old porcelain fuses with the plug in circuit breakers and also bought some new appliances including heaters. My maximum demand calculated on this power circuit is about 34A so the 32A circuit breaker would not be sufficient but the 10mm cable might be alright still have to find my AS3008 to check this. I can't find the power requirements on the self heating dishwasher , condenser dryer and 5kg washing machine, could you tell me what input power i should use for my calculations?. On the ID for fridge it uses 325W of input power does that sound right? I have given the above appliances guessed values so i could determine my maximum demand calculation of 34A using 50% of the load for each one above including two microwaves at 1600W each and a 2400W heater + 10A for GPOs on circuit. It is a high demand power circuit as all of the above appliances are on the same circuit. Did i calculate the maximum demand correctly?

[thatirwinfella]

in most cases the largest appliances used in a home are located in the laundry and kitchen, and the trend nowadays is to seperate the circuits, in many cases having the kitchen on two circuits.

if you get the circuit split you'd possibly get away with two 16 amp breakers, or a 16 and a 20.

10mm cable is still pretty big stuff and there'd be getting it to fit into socket outlets and switch terminals. using multiple smaller circuits will allow a smaller cable to be used, givving cost benefits... i don't know about 10mm but even a 6mm circuit of any length gets pretty expensive. 16 amps can usually be done in 2.5mm unless voltage drop is an issue.

also, 10mm twin and earth [if you can get it, the largest i've seen is 6mm] would be extremely bulky and there would be difficulty replicating the path of the existing circuit... most sparkies use a 25mm diameter auger bit for going through studs and noggins.

is there another power circuit you can plug your heater into... thats 10amps gone then and your breaker may stop tripping.

also, as you do seem to be making an effort to get everything compliant, you'll need an RCD if you don't have one already. That complicates things, but if you're getting a sparky to test it it wouldn't take them long to do.

I still strongly believe and suggest that a licenced electrician should do it.

[Ashore]

The reason why the16A circuit breaker is tripping is because recently we replaced the old porcelain fuses with the plug in circuit breakers and also bought some new appliances including heaters. My maximum demand calculated on this power circuit is about 34A so the 32A circuit breaker would not be sufficient but the 10mm cable might be alright still have to find my AS3008 to check this. I can't find the power requirements on the self heating dishwasher , condenser dryer and 5kg washing machine, could you tell me what input power i should use for my calculations?. On the ID for fridge it uses 325W of input power does that sound right? I have given the above appliances guessed values so i could determine my maximum demand calculation of 34A using 50% of the load for each one above including two microwaves at 1600W each and a 2400W heater + 10A for GPOs on circuit. It is a high demand power circuit as all of the above appliances are on the same circuit. Did i calculate the maximum demand correctly?

Hardy as to your calcs starting load on motors can be as high as 6 times running load and Un fortunately the plug in circuit breakers will trip on instant loads in a shorter time frame than the old porcelain ones.

How ofter is all the load on at the same time ?Did you notice any one item coming on line that causes the breaker to trip.

If you have axcess to the existing circuit could you run another circuit to the kitchen or laundry along side the existing one and put a second GPO next to the original to run the fridge washing m/c etc using the existing cable as a pull through ?

One thing about your original post why do you need a 300mm x 300mm trench, that is why so big for 20mm conduit? :confused:


Rgds

[journeyman Mick]

Felixe,
WRT the legislation, the law allows for work to be carried out by people who aren't licensed electricians if it is done under the supervision of a licensed electrician. Otherwise apprentices would not be allowed to do much at all . Also, on many of the larger jobs a company will have one licensed electrician who is ultimately responsible for that job and a swag of other electricians, some licensed, some not as well as apprentices and trades assistants. I'm not sure if the law requires that the license holder has to be there looking over my shoulder as I do the work, but if anyone ever asks, then yes he was.