Another stupid sparky question

[Legion]

Great stuff. Can you give me a summary of 32A tables, since that's what I've standardised on?

[soundman]

I have not come across tables for flexes above 4mm2......I may not have baught that standard.....or quite likly its is not particularly specified for flexes over 4mm2.

But from a rough extrapolation on 32 amps
I expect
4mm2 to be good for about 30 meters general and 20 meters high start current
6mm2 to be good for about 50 meters general and 30 high start current
10mm2 to be good for about 80 meters and 50 meters

cheers

[Vernonv]

Here is a quote from AS/NZS 3000:2007. Make of it what you will.

1.4.36 Cord, flexible
A flexible cable, no wire of which exceeds 0.31 mm diameter and no
conductor of which exceeds 4 mm2 cross-sectional area, and having
not more than five cores.

[soundman]

Indeed correct.....but that is intended to apply to appliance cords typically single phase and single phase extension cords.

There are three phase cables heavier than 4mm2 square that while by definition are not "flexes" OR "flexible cords" are fine stranded and reality flexible cables.

regardless the voltage drop and current capacity issues remain the same.

cheers

[RustyArc]

I've got a couple of 60 or so metre 2.5mm2 3C+E orange circ leads that I think used to be for a bore pump. They're wired to 10A plugs with two of the conductors paired to reduce voltage drop.

I've used a welder off the end of the two hooked together (120m total) with no problems, although it's an inverter unit and only running 100A or so.

[Karl Robbers]

Seeing as we are talking cables and plugs here, I thought I'd drop in this little gem.
I recently acquired a welder and when I unrolled the power cable, in among the rolls of cable was an adaptor lead. 20A male 3 phase to 32A female 3 phase, connected by around 4MM 3C + E flex. I surely do not need to go into dramatic detail about how naughty this is, nor the pitfalls of such practices, but you will never guess what else I found on the lead. A genuine, bona fide, super dooper test tag
This welder originally came from a large fabrication workshop that exports work both Australia and Worldwide. I cannot categorically say that it was they who set up the lead and had it tagged, but I doubt that the private citizen who I acquired the welder from, (cost a fortune too - a whole six pack of Boags Premium Light!), would have bothered with testing and tagging.

[soundman]

I never cease to be amazed at what I see with tags on.

Frankly There have to be a lot of either dumb or wreckless electricians out there.

Don't they realise that by putting a tag with their licence number on it they are producing evidence that ties the blame directly to them.

So if some one gets killed or injured or the item causes property damage ....like a fire...putting a tag on something that is blatantly non compliant puts the owner of the licence number squarely in the frame......the electrical authorities will give em a spanking.......but the insurance companies will take their house..

I'd go as far as to say the majority of electricians out ther would not even know in detail what makes something compliant and what are grounds for defecting an item.

Most think that the contents of AS3000 and maybe AS3760 is all they need to know to test & tag

I think some of this has to do with the price of standards and the inability to access them without paying the rediculous prices.

As I may have mentioned..I have just coughed up for what I believe I need to have to know my busness..and that cost me $1200 in round figures....& I'm not full ticket sparky and there is lots of stuff I don't need to know.

Not so long ago, if you looked on the dash or front seat of almost any electricians van/truck, you would have found a beaten copy of AS3000.....these days there are plenty of electricians who would not have even seen a coppy in the last 12 months let alone owned a current copy.

But that is no excuse for tagging something that is blatantly noncompliant and illegal.

Here is a thing......the standards no provide a lega and safe way to do what that dodgy adaptor did...and that is to allow an item with a higher rated plug.....but not drawing maximum capacity to plug into into a lower rated socket

Its simply a matter of fitting an appropriatly rated circuit breaker in the cable...from memory that breaker also has to provide earth leakage protection as well.

But back to test & tag......serioulsy most test & tag work that is done is token effort......yeh they may have a quick look at the item and they might run the megger or pat tester over it.

But do they unroll every extension cord and examine every inch, do they do a multiple point earth continuity test to make sure all exposed metal parts are properly earthed..and I could go on....realy business does not want to pay to have "in servce electrical compliance inspection and testing" done properly.

I don't know what the going rate is at the moment, but a few years ago there where companies quoting $5 an item to test & tag.......That would have meant each worker would need to do 12 to 16 items an hour to make a profit on labour alone.......I would be flat out filling out the book and sticking that many tags on in an hour.

cheers

[Vernonv]

The test and tag could have been done by a non-electrician, who had done an "appropriate" test and tag course.

[Karl Robbers]

When you think of it, you don't even need a test and tag course.
You can buy the tags over the counter or online and it is not too hard to copy someones details off a tag. Illegal, immoral, naughty and despicable as that may be, how many inspectors on a worksite would ever realise?
In a previous workplace, we only ever tested and tagged as we loaded the truck to go onsite. Grab the tags and pen out of the bosses office drawer, use the licence number and details from the motor re winder next door, (who knew what we were doing and gave us his blessing), check the leads, (sort of, depending on who did it) and away we go. In ten odd years working there and on site, my leads were never scrutinised by anyone onsite.
The testing and tagging industry in its current incarnation is purely a money maker and achieves nothing.
I support proper testing and tagging, although that really only covers the equipment on the day it was tested, the insulation could be cut the following day and the tag still be valid for another three months.
I guess education is the key and complacency the enemy.
Anyone who has seen a 1000V cable blow under load will never underestimate electricity again.
True story. For reasons best known to themselves, a jumbo operator had a 1000V pump cable running over the work platform that he was standing on. Somehow, we will never quite know how, because that 3-400mm section of cable is now vapourised, there was a short circuit and the cable arced through the platform. Standard procedure being to stay on the rig and await the underground sparkie to verify all as dead, that is what he did. The radio call was the humorous part for us though.

"Copy shift boss."
"Yep, copy."
"Uh, boss, I've had a cable blow out. I'm okay and the sparkie is on his way."
"Uh, right, I'd best come down then."

"Uh, you still there boss?"
"Yep."

"Uh boss, before you come down, could you go up to my locker and get some clean overalls, I've s#@t myself."
"Yeah, that would have been a shock, ha ha."

"Uh, no boss, I've actually s#@t myself.............."

Electricity, you can't see it but it ouches!

[soundman]

Now here is the thing.

The obligation is on the electrical worker to controll the use of his licence number and document his work.

The tag is only a superficial sign of the whole deal.
The details of the tag..... the workers licence number.......the date AND the workers signature are suposed to be recorded in the log book. I addition the worker is suposed to issue a cerificate of test ( warrant of fitness in NZ) AND keep coppies.

Thus, a complete paper trail should exist proving who and when the tags where affixed.
Further that paper trail, in particular the log book should show a history of compliance.


There was a question in an exam on a skills maintenence course I was on......."there is an electrical incident, you have been identified from your number on a tag on a cable that was involved.....What do you take with you to the hearing to prove your inocence?

The answer is...your work diary, detailing work for the day of the date on the tag, coppies of your certificates of test and examples of the tags you use.




NOW...here is how government regulation works these days.......they don't pay large numbers of inspectors to go out and routinely inspect things....and catch people doing the wrong thing......they frame rediculously large penalties and wait for something to go wrong...then the inspectors come out a start kicking asses.

So when there is an "electrical incident"...the inspector will go thru the place like a dose of salts.......matching up the tags to the log book and the log book to the certifcates of test.

So Mr Motor rewinder.....this lead has your number on this tag...prove to me why you should not be prosecuted.

Mr motor rewinder says.....Not my tag.....not the brand of tag I use....the tag number does not show up in my certificates of test and that is not my signature in the log book..( if the long book exists.

So Mr Foreman..you are the responsible person in this workshop........

So Mr business owner........

and thus the invectigation proceeds.

AND everbody in the chain is liable for presecution seperately and for every occurance...and you can bet ya that the bloke at the bottom of the chain is not going to carry the can when he is threatened with prosecution on multiple levels of responsibility.






Then there is the complete and utter cop out, that inpsction, testing and tagging is only good for the day it is done.

There was never bigger crock.

Inspection testing and tagging is intended to locate and identify faults before they kill or injure someone.

The way the electrical system in Australia is engineered and regulated, it is very, very hard to get killed or injured because of a single fault or non compliance.
The system contains multiple levels of protection and in general at least two hazards must exist to represent immediate danger.


I have never...not once.....done a test & tag session and not found something that needed attention..yesterday it was a cable that had stretched and was no longer properly strain relieved at the plug......there is no way it was possible to get killed or injured from that lead.....even though it was non compliant & I rightly failed it...because there where other levels of protection inherent in the situstion.

BUT if that lead continued unrectifed, in due course it may develop another fault OR another situation may occur to make that lead.... with one layer of protection removed.....deadly.


Inspection testing and tagging is designed to ensure that all the levels of protection are in place and to detect faults and damage that has occured since the last inspection....faults that may remove one or more layers of protection.

OH..and remember...every worker.....every time...is suposed to conduct their own visual inspection of every electrical item before they use it.

cheers

[Karl Robbers]

I hope you didn't get the impression that I condoned what went on. I certainly did not and do not. I was purely pointing out that the current system is widely abused and flawed in that it is reactive. Bums are kicked after the incident.
We agree that every worker is expected and legally obliged to carry out a pre start check on every lead and tool prior to use and during use if there is reason to suspect that there has been a change that may affect serviceability. Which really does coincide with my comment that a test and tag is really only 100% relevant at the time of inspection, as are drivers licence tests and roadworthy inspections. Events occur that render them invalid.
Don't get me wrong, I support testing and tagging, but it is only a very small part of the overall picture in practical terms.
Why do we not have a system where your licence number is required to purchase tags? Why do site supervisors not check tags and leads when they check the date on your hard hat?
The average worker still does not understand their responsibilities under the relevant acts and regulations, nor the potential penalties they face and a great many small businesses do not want to know.

[Legion]

I like the way this thread has evolved. I have learned a lot, from everyone. This is why I ask dumb questions, so that when I make decisions I can justify and feel more confident in my reasoning.

[Karl Robbers]

No such thing as a dumb question and a day without learning something is a day wasted.

[soundman]

No doubt Karl you are just pointing out what goes on......and hell yeh it does go on.

BUT this "testing and tagging is only good on the day its done" is a very commonly sprouted pile of crap..and a lot of people believe it.

The events that occur after inspection do not take away from the validity of the tag......the tag should show, that at the time of inspection, that item complied and thus had the multiple layers of protection in place...thus it should be capable of providing protection against moderate unfortunate events.

AND remember IF an item is subjact to rough handling or arduous use, its inspection peroid should be more frequent...in some cases as little as 30 days.

There is no licence required to purchase tags, but every electrical worker is required to put his own licence number on every tag he affixes.

There are situations where a non licenced person can affix a tag.

A trained but non licenced person has limited ability to attach tags.

An untrained unlicenced person can affix a tag to a "NEW" item and record same in the log....there is an asumption that a "new" item is compliant.

as far as the site super checking tags...... any site super that values his own ass most dertainly does.

As far as people not knowing the regulations that apply and their obligations....weeell...that is another government attitude thing.......no government seems to be interested is adequate public information campaigns when regulations change ( in any area)....they will just say its your respinsibility to know........and yes...the rediculous price of standards.

cheers

[Michael G]

Getting back to only being slightly off topic,

There are three phase cables heavier than 4mm2 square that while by definition are not "flexes" OR "flexible cords" are fine stranded and reality flexible cables.

What is the definition of a "flexible cord"? I have a 8m 3 phase extension cord that I use for my mill (20A). I've always wondered whether it should be replaced as while it flexes it looks more like the sort of cable you would strap to a tray.

Michael