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153 posts

Master Geek
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  Reply # 1920457 16-Dec-2017 07:52
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gregmcc:

Lastman:


gregmcc:


Lastman:
gregmcc:



There’s plenty of You Tube videos demostrating just that but I’ll start by saying that RCDs are making ELFI somewhat redundant because you are not required to do one to test a circuit protected by an RCD. An actual physical test of the RCD trip is all that is required. I’m happy to provide a link for that if you require.

I never said the man in the street should be able to do electrical work. He will not have a meter to do an ELFI test, just that we should remove some of the archaic structures around these professions.


 


Thank you for proving that you really don't know what you are talking about, the question was never about RCD's, not all standard domestic power point circuits have RCD's the reason for EFLI is about ensuring protection devices trip in the correct time. This is the kind of skill that is learnt on the job.... the stuff apprenticeships are made of


 


 


 


 




https://www.electricalforum.co.nz/index.php?action=more_details&id=1510655103


 


 


I guess you forgot that I did say the test was *never* about RCD's, it was about how to preform a EFLI test with power and without power and what a pass result would be and what a fail result would be


 



Ok, I'll play the game ( haven't looked at other replies)...and give a longish answer. I don't have access to the standards (nor the time) so it will also be a general answer.


The NZ power system is predominately a TN-C-S system (or strictly described as a MEN-multiple earthed neutral), earth and neutral (PEN) come from the transformer as a single wire. At the distribution board the PEN goes to the earth busbar which also has a earth wire connected to an earth stake. The earth busbar is connected via a link to the neutral busbar and earth and neutral then go their separate ways in the building. Phase comes in via a single wire or three for 3-phase.


An earth loop impedance test is to ensure that the earth (and neutral) are A) actually connected and B) that the fault impedance is less than a certain value so that there is sufficient current in a fault condition that the circuit breaker will trip. That circuit is the journey from the point tested all the way through the transformer, back through the relevant return wire to the testing point.


Ze is the external impedance ie tested from the switchboard with power to the building off (and may require other earthing ie plumbing earths, to be disconnected). For TN-C-S you don't need to test N and E separately ie L to N fault as they are the same wire, for other earthing systems you may do.


Zs is the impedance at the final circuit e.g the power point. I don't now the exact details or the ohm value (again I don't have access to the standards). I assume though the meter tests the E and N paths (as they are now seperate) and uses the maximum of the two and that value would need to be less than a specified amount. This might depend on the specs of the circuit breaker as well or it might be standard.


I don't know the test for no supply available (but it is explained in the standards). I assume the impedance back to the switchboard is measured and added to a standard or general value of Ze to give an approximation. That is just a guess. This test is generally for electricians putting in new supplies where they don't yet have power. 


I did do brief research basically to remember some of the terms.


 


 



 


Fantastic, looks like a copy and paste from a standard, some of which is incorrect for NZ. Looks like you really don't have an understanding of why a ELFI test is done, or what a pass or fail test may be.


You did say "The electrical trade, especially in regard to house installations, is intellectually trivial. You could teach anyone the basis of it in a lazy weekend."


I am thinking that you really don't know much about the electrical trade. But if you do want to learn, the domestic electrical is a good starting point.


 


 



It was my own work. It is relevant to NZ. I don’t have access to the NZ standards for some of the detail.
It is wordy but expressed as a diagram (the earthing system to distribution) it is very simple.

I seem to have got under your skin. I will refrain from further discussion.

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  Reply # 1920462 16-Dec-2017 08:13
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Rikkitic:

 

Lots of hostility here. It does seem rather defensive. I have to wonder (don't know, of course) how much this just has to do with territorial protection. Unless a homeowner is doing a new install from scratch, I doubt things like earth loop impedance tests are going to be a major issue. I think the point being made (though I can't speak for that person) is just that a lot of specialised training isn't really necessary for a lot of everyday jobs. Maybe it is for some things, but not for everything. As an aside, it isn't for doctors, either. That is why nurses are being given more responsibilities.

 

 

I'm not a tradesman but I work with them on a daily basis in the building/construction industry. The tone of some of these posts, trivialising a tradesmans apprenticeship and skills, is quite frankly insulting. Good tradespeople are incredibly skilled and have a practical knowledge of how to make systems work that many professional people just don't understand. I'm an engineer by training and I've learnt more about building services from tradespeople than I have from study or the internet.

 

The thing that seems to get missed by people trivialising tradespeople is that these jobs have physical skills that require a great deal of repetition to learn. The bespoke nature of the industry (nothing is ever the same from one building to the next) and the impact on life safety nature of the likes of plumbing and electrical work means that there are very good reasons that these are regulated industries.

 

The level of knowledge of building, and building services in particular, in the general population is pretty non existent. To realistically expect the lowest common denominator to install fixed wiring or sanitary plumbing is insane.

 

Your analogy of more limited work being conducted by less skilled people exists now, that is why there are ESA and EST qualifications available.

 

Innovation comes from designing out skills, not by lowering the bar so incompetent people can perform them. For example modular wiring systems don't necessarily need an electrician to install them as they are plugged and socketed. 


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  Reply # 1920466 16-Dec-2017 08:49
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MadEngineer:

 

It's all fun and games until someone runs some copper between two buildings and wonders why they get 415 volts.  Good luck learning how that may come about and the rest in a weekend.

 

 

This should really be flagged as the answer to the original question!

 

 




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Ultimate Geek
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  Reply # 1920482 16-Dec-2017 09:31
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sbiddle:

MadEngineer:


It's all fun and games until someone runs some copper between two buildings and wonders why they get 415 volts.  Good luck learning how that may come about and the rest in a weekend.



This should really be flagged as the answer to the original question!


 



The original question was is it normal practise to charge more labour when wanting to supply own quality pdl sockets and lighting which seems yes it is normal practise. I was not asking about the capability or skill level of a sparky. It does come down to design as well . The quote regardless of price I will be looking elsewhere as i wasnt in sync with the electrican from a design perspective . Thanks for all the views I was generally interested as have never been quoted this before the post wasn’t to debate the skill levels or cause offence to tradies

UHD

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Ultimate Geek
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  Reply # 1920508 16-Dec-2017 11:03
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I think charging more for labour when a client supplies may be normal for a number of tradespeople, most often those who haven't worked with you before.

 

I have a sparky and plumber I use regularly for rental repairs and other various projects who don't charge me more if I supply my own kit. They quote me the same hourly rate (either single guy or team of two depending on the job) and always just charge me wholesale on the materials or use what I supply. They charge a call out fee for any weekend or after hours work but nothing for business hours because they fit me in between other jobs.

 

This is possible because I work with them all the time and they know I won't toss them some Bunnings garbage to install then moan when it fails in 11 months time.

 

In OP's case of an extension with 50+ lights and a large number of power sockets you're saving $150 or so on the materials but given the size of the job it is just not really worth it. All it would take is a couple of calls from the sparky saying "hey, we actually need x more of this" and you having to run into town to make the "savings" nil.

 

Alternatively, I'd shop around til I can find someone who won't charge a mark up on materials. Keep in mind that you'll have less of a headache paying $2 per fitting installed by a reputable sparky than paying nothing and having them installed by a cowboy.




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Ultimate Geek
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  Reply # 1920545 16-Dec-2017 12:45
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UHD:

I think charging more for labour when a client supplies may be normal for a number of tradespeople, most often those who haven't worked with you before.


I have a sparky and plumber I use regularly for rental repairs and other various projects who don't charge me more if I supply my own kit. They quote me the same hourly rate (either single guy or team of two depending on the job) and always just charge me wholesale on the materials or use what I supply. They charge a call out fee for any weekend or after hours work but nothing for business hours because they fit me in between other jobs.


This is possible because I work with them all the time and they know I won't toss them some Bunnings garbage to install then moan when it fails in 11 months time.


In OP's case of an extension with 50+ lights and a large number of power sockets you're saving $150 or so on the materials but given the size of the job it is just not really worth it. All it would take is a couple of calls from the sparky saying "hey, we actually need x more of this" and you having to run into town to make the "savings" nil.


Alternatively, I'd shop around til I can find someone who won't charge a mark up on materials. Keep in mind that you'll have less of a headache paying $2 per fitting installed by a reputable sparky than paying nothing and having them installed by a cowboy.



The sparky I normally use doesn't charge more so was suprised when he told me. Appreciate the advise though

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Master Geek
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  Reply # 1920606 16-Dec-2017 17:02
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It really depends on the relationship you have with the sparky. For most jobs the mark up on materials would be considered to be part of the sparkys income. However where there is an ongoing relationship both parties would come to a mutually acceptable arrangement. It's a bit like the difference between a wholesaler and a retailer.

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Ultimate Geek
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  Reply # 1920736 17-Dec-2017 09:36
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FWIW, I was building in Glenfield, West Auckland and the Bays in the 60's - 70's. I only used subs who I liked and trusted.

 

Once I knew I could rely on each subby, I rarely asked them for job quotes, instead relying on my own estimate of each sub-trade so that I could quote the customer for the house.

 

So, essentially, the subs worked for me on a charge-up basis. It made for a happy job and good relationships all round.

 

And re markups, I didn't charge customers more than trade price for materials.

 

However, there wasn't the cynicism and hustle in the building business back then, nor were the crazy overheads of compliance, permits and OSH requirements.

 

 


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  Reply # 1920740 17-Dec-2017 10:22
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The overheads of compliance carried by every electrician just so Energy Safety doesn't have to manage the SDoc system. Why the importers and manufacturers don't produce their documentation to ES and get a registration number instead of every installer having to hold or have access to copies escapes me.

Then there's the issue of trade price. Some trade prices seem higher than Big Box retail. That's when it insults the customer.

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Master Geek
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  Reply # 1921471 18-Dec-2017 19:49
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Bung: The overheads of compliance carried by every electrician just so Energy Safety doesn't have to manage the SDoc system. Why the importers and manufacturers don't produce their documentation to ES and get a registration number instead of every installer having to hold or have access to copies escapes me.

Then there's the issue of trade price. Some trade prices seem higher than Big Box retail. That's when it insults the customer.


This reminds me of the time I bought a shower mixer via work trade account thinking that it would be the best deal then next week saw it at Bunnings for $100 less.

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  Reply # 1923129 21-Dec-2017 12:48
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Handle9:

 

 

 

Your analogy of more limited work being conducted by less skilled people exists now, that is why there are ESA and EST qualifications available.

 

 

 

 

Personally, the 60% pass mark is way too low, considering that they are working with lethal voltages, and customer appliances.

 

It should be 85% or better, the questions are not that hard ...

 

A gun license requires 100% pass, and has just as much lethal potential.

 

 





My thoughts are no longer my own and is probably representative of our media-controlled government


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  Reply # 1923173 21-Dec-2017 13:51
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SepticSceptic:

 

Handle9:

 

 

 

Your analogy of more limited work being conducted by less skilled people exists now, that is why there are ESA and EST qualifications available.

 

 

 

 

Personally, the 60% pass mark is way too low, considering that they are working with lethal voltages, and customer appliances.

 

It should be 85% or better, the questions are not that hard ...

 

A gun license requires 100% pass, and has just as much lethal potential.

 

 

 

 

The whole electrical exam system is stuck in the dark ages, books only and a race against time.

 

 

 

It's time to allow the use of computer/phone/tablets loaded with the relevant standards just like is already done in actual real life.

 

 

 

 


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  Reply # 1923251 21-Dec-2017 15:45
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richms:

 

If you're calling tradies and getting quotes, they will pad them out to the extreme to cover unforseens, and their time they take to make the quotes etc.

 

 

My recent work was time & material and if I want the contractors will provide timesheets. If that timesheet doesn't match actual work done it's either an unintentional mistake or it is intentional fraud. 

 

 

 

 


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  Reply # 1923252 21-Dec-2017 15:49
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sbiddle:

 

Electricians make money two ways - on labour and parts.

 

You don't go into a restaurant with your own steak and then expect the chef to cook it and give you a big discount..

 

 

Depends on your contract with your contractor. If it is for time and materials he can only bill for time worked and materials supplied, and he may well insist on supplying the materials. But he can't write down 100h on his timesheet if he did 80.

 

 

 

 


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  Reply # 1923253 21-Dec-2017 15:51
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sparkz25:

 

and when you do supply your own crappy arlec sockets and they fail who is the first person you blame? the sparky of course, stick with the pdl 600 series as its a good reputable brand and it works and has done for years, looks half decent too 

 

 

No I'd blame the socket not the sparky, and I'd expect to pay him to come and replace it.


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