Untested 15A Extension Leads

Nomad246 · Senior Member

Untested 15A Extension Leads

rockylizard · Guru

Gday...

Thanks Nomad .... timely, and wise, advice

Cheers - John

hako · Guru

I've had a few of those clear connectors overheat and burn internally due to poor mechanical connections....it turns black and eventually burns through the insulation so can be pretty dangerous. Mine were 10amp.

Yuglamron · Guru

Power boards can be dangerous too.

My house burnt down in'93 due to a power board.

Fire investigator said it was due to the little neon that shows power is on,When I put plugs in and out over a period of time it broke the weld between the neon and the live feed causing small arcs which set the plastic on fire.

It was all due to the design and the plastic used back then. I am told the plastic is different now.

But all electrical stuff plugs/boards should be looked at and replaced if they are old,cracked etc.

I was lucky we were at a drive in with the kids when the fire started.A few hours later.....................?

Nomad246 · Senior Member

That's true, power boards can be dangerous and a fire risk. You have suffered loss to testify to that.

Cheers

aussietraveller · Guru

I know its not mandatory to have caravan leads tested at regular intervals like it is for all portable industrial leads and equipment but the cost of not doing it could be catastrophic I have a son who is a licensed Test and Tag electrician and he said there is no way you can tell a lead is safe without proper testing, always best to be on the safe side even if it costs a couple of dollars.

patrolst · Senior Member

And if it tests OK you are fine, if not get an licensed electrician to repair the lead.

Nomad246 · Senior Member

aussietraveller wrote:
I know its not mandatory to have caravan leads tested at regular intervals like it is for all portable industrial leads and equipment but the cost of not doing it could be catastrophic I have a son who is a licensed Test and Tag electrician and he said there is no way you can tell a lead is safe without proper testing, always best to be on the safe side even if it costs a couple of dollars.

Very true Aussietraveller,,,, my reason for starting the post was,,,, I was told it was a good lead,,, looked good, felt good,,, but when tested it was below safe.

I'll bet there are many that take my old Uncles approach and have a defective lead,,,,, but hey it works!

Compliments of the festive season

E&OE

blaze · Guru

Trouble with test and tag is the lead can become faulty withing hours of test, people then pick it up and sight the tag and assume that its safe to use. Not saying its a bad idea but you should give a lead a visual check before use and periodicly when in continuos use.
cheers
blaze

Nomad246 · Senior Member

patrolst wrote:
And if it tests OK you are fine, if not get an licensed electrician to repair the lead.

Hi PatrolST ,,, can I add,,,, the cost of a new lead might outweigh having the old lead repaired at a cost to the owner.

In my case it cost over $20 for repairs without labour charges. New lead would have been about $40 or so.

My advice to most, without access to free qualified labour, would be buy a new lead and cut the old one into very short pieces and bin it.

However, on another tack, wouldn't it be good for properly qualified Nomads to offer a testing service for a cuppa as payment. (that'll open the gate for the "professionally" unqualified) And as law with the Electricty Act in Victoria you would need a Contractors Licence for hire or gain,,, even if the gain was a cuppa.

ST ,,, compliments of the season

Cheers

E&OE

Nomad246 · Senior Member

blaze wrote:
Trouble with test and tag is the lead can become faulty withing hours of test, people then pick it up and sight the tag and assume that its safe to use. Not saying its a bad idea but you should give a lead a visual check before use and periodicly when in continuos use.
cheers
blaze

Blaze, that's very true, something tagged today may not be the same tomorrow. It is the owners/operators requirement to have visual inspections inbetween tests.

Obviously if the caravan park guests drove over my lead for days I would want a new inspection and possibly test

E&OE

Cheers and have a safe and happy Xmas

hako · Guru

I reckon a good test of whether the lead is in good condition is to check the temperature of both ends of the lead after it has been used on a moderate load - like running the A/C. If the active pin is hot then consider the cable to be dangerous and liable to short internally.
Tag and test may be a good system but you have to find an elec who has the time to do the test - take it to him and then return to pick it up. On a 10 amp cable it will cost more to tag and test than to buy a new lead and pretty soon the same will apply to 15amp cables the way prices have come down.
Regards
Denis

oldtrack123 · Guru

hako wrote:
I reckon a good test of whether the lead is in good condition is to check the temperature of both ends of the lead after it has been used on a moderate load - like running the A/C. If the active pin is hot then consider the cable to be dangerous and liable to short internally.
Tag and test may be a good system but you have to find an elec who has the time to do the test - take it to him and then return to pick it up. On a 10 amp cable it will cost more to tag and test than to buy a new lead and pretty soon the same will apply to 15amp cables the way prices have come down.
Regards
Denis

HI Dennis

ANY heat is a sure sign of problems with either load carrying components, but it does not in anyway check or indicate bad earth continuity

The real safety requirement against shock

Peter

Nomad246 · Senior Member

That's a very good point Oldtrack123, about a faulty earth in a lead.

Faulty earths in leads could render a ELCB inoperative.

Cheers

PeterD · Guru

Nomad246 wrote:
Faulty earths in leads could render a ELCB inoperative.

I doubt it. The ELCB has a core balance transformer in it. This consists of a ferrite core with equal numbers of turns of wire of both the active and neutral conductors. There is another winding with many turns that operate the switch. Whilst the current in the active and neutral conductors is identical the mains current flowing through the transformer the resultant opposing currents result in no magnetic flux being induced into the core of the transformer. If there is no magnetic flux induced into the core there is no current induced in the third switching winding. The switch does not operate under this condition.

If something happens in the active line like a high resistance fault or someone touching a live wire then all the current flowing flowing in the active will flow through the core balance transformer. However the fault current does not flow back through the transformer. With the two mains current in the mains conductors now not being equal there will be some magnetic flux induced in the transformer core. This magnetic flux will induce a current in the third winding and then trip the switch. It does not matter whether the fault current flows through the earth wire or direct to ground. The earth wire does not go through the transformer.

Big Gorilla · Guru

I am electrician and although I followed other pursuits in my working life, I've always kept my license current. I had been thinking of putting a sign on my Motothome that I test and tag leads. I charge $6.00 each. Reading this post perhaps I will go ahead with the sign. I wander around Tasmania and Victoria and occasionally into Qld and Sth. Aust. so maybe I would get a few requests. Also I'm getting lazy in my old age with a few aches and pains, and I guess I haven't put a sign up to date is that I really don't want to be crawling in, around and under vans fixing other electrical problems, although if anyone was really stuck, I most certainly would help out.

oldtrack123 · Guru

HI PeterD

Thanks for correcting my very senior moment disbelief

Of course the real problem with a high resistance earth, is faulty OLCB operation NOT RCD wink

Nomad246 · Senior Member

Big Gorilla wrote:
I am electrician and although I followed other pursuits in my working life, I've always kept my license current. I had been thinking of putting a sign on my Motothome that I test and tag leads. I charge $6.00 each. Reading this post perhaps I will go ahead with the sign. I wander around Tasmania and Victoria and occasionally into Qld and Sth. Aust. so maybe I would get a few requests. Also I'm getting lazy in my old age with a few aches and pains, and I guess I haven't put a sign up to date is that I really don't want to be crawling in, around and under vans fixing other electrical problems, although if anyone was really stuck, I most certainly would help out.

Good idea Big Gorilla, my earlier comment was testing only not including the cost of purchasing tags.

Just shows, once an electrician makes a gentleman for life.

Cheers

Nomad246 · Senior Member

PeterD, In your rush to provide an overview of the construction and operation of an ELCB you have overlooked a critical piece of this potential situation.

As in your summary "It does not matter whether the fault current flows through the earth wire or direct to ground."

Knowing that a caravan sits on rubber tyres, and possibly has no other confirmed and permenate current path to ground, a lead with good earth is the only path where the fault current would go safely.

OldTrack123 was on to it clarifying it as a high resistance earth and earlier as bad earth continuity.

Caravans and motorhomes are constructed in a way that is (electrically) above ground, hence my statement that normal operation of safety devices could be affected.

jimricho · Guru

Nomad246 wrote:
PeterD, In your rush to provide an overview of the construction and operation of an ELCB you have overlooked a critical piece of this potential situation.
As in your summary "It does not matter whether the fault current flows through the earth wire or direct to ground."
Knowing that a caravan sits on rubber tyres, and possibly has no other confirmed and permenate current path to ground, a lead with good earth is the only path where the fault current would go safely.
OldTrack123 was on to it clarifying it as a high resistance earth and earlier as bad earth continuity.
Caravans and motorhomes are constructed in a way that is (electrically) above ground, hence my statement that normal operation of safety devices could be affected.

Apart from the fact that I disagree with your premise anyway, I point out that when my rig is parked and set up for "camping" the metal corner jacks either rest directly on the ground or on wooden blocks which may sometimes be wet.

Any current that does not pass through the elcb, rcd, safety switch (or whatever name you give it) will trip the breaker. That residual current could well be flowing through a very fine specimen of homo sapiens hence the value of these devices.

As guardian of the forum's literary standards perhaps you can explain what the word "permenate" means for the benefit of we (us?) lesser mortals. wink

oldtrack123 · Guru

HI
Re

"OldTrack123 was on to it clarifying it as a high resistance earth and earlier as bad earth continuity"
I should point out that:
[1]
The earth fault loop impedance [resistance] requires special attention for the safe operation of OLCBs

[2] MAx impedance is determined by the trip characteristics of the overload CB being used.
The total earth loop impedance cannot exceedthose specified in the standards[9.5Ohms for a 6Amp type"B"olcb
for a 16A olcb the max is .59Ohms for type "B'
Those loop impedance values will give a max 0.4secs trip time

A 16A type" D'the max lop impedance SHALL be 1.15Ohms for 0.4sec trip time

[3] those values are far from a HIGH resistance in the usual context

[4] all practical purposes the metal legs sitting on wet or dry ground cannot meet that requirement/
An OLCB is very unlikely to trip

[5]re SHALL be a complying metallic equipotential earthing connection THROUGHOUT the system

[6]t includes extension leads connecting all Class 1 appliances /devices[inverters ,generators, vans camper,trailers,Motor homes tents etc

where ever a ac voltage of 50V plus is involved

Peter

ps I would suggest "permenate" is a typo & "permanent" was intended wink

-- Edited by oldtrack123 on Tuesday 25th of December 2012 04:06:06 PM

-- Edited by oldtrack123 on Tuesday 25th of December 2012 04:09:23 PM

oldtrack123 · Guru

hako wrote:
What is an OCLB?......it's not a typo as it's been mentioned a few times.
I Googled it but found nothing in the first 3 pages .

HI hako

should be OLCB'[OVER load circuit breaker]

Hang on ,I just checked back I did have OLCB

,But is a problem I have when typing/ writing where my brain & fingers are not synchronised [I jump letters ahead & getting worse]

Spell check often finds them ,but not always

Peter

-- Edited by oldtrack123 on Tuesday 25th of December 2012 10:50:15 PM

hako · Guru

What is an OCLB?......it's not a typo as it's been mentioned a few times.
I Googled it but found nothing in the first 3 pages .

Big Gorilla · Guru

wasn_me wrote:
Nomad246 wrote:
My van has an external power point (which i think is pretty standard). I use toaster, kettle, frypan, drill from this piont. I'm standing on the ground when using them, therefore a path to earth

I have an external outlet also. If your van is correctly wired, you will find a Certification attached somewhere in your Van, usually next to the house batteries. The Certification is by a Licensed Electrician that the van/motorhome is correctly wired and components correctly installed, meaning the installation is electrically safe.

The usual method is that the van/motorhome frame is connected to an earth wire. The fact it is on rubber tyres is irrelevant. This earth will run back thru the inlet, thru the cord back to the power point into which you have plugged your van/motorhome. The electrical installation at the house or caravan park supplying the power point will have the earth wire connected to the neutral (return) wire, and also be connected to an earth stake or G. I. waterpipe in the ground. Any fault in the van will usually trip the ELCB in the van, however if for some reason it doesn't, the return path thru the power point you are plugged into will trip the circuit breaker, or blow the fuse supplying power to that power point. You are therefore quite safe using your appliances plugged into the external outlet.

I hope you can understand this explanation. Without getting technical, I've tried to explain how the earthing system works in simple language.

-- Edited by Big Gorilla on Wednesday 26th of December 2012 10:37:27 AM

wasn_me · Guru

Nomad246 wrote:

Knowing that a caravan sits on rubber tyres, and possibly has no other confirmed and permenate current path to ground, a lead with good earth is the only path where the fault current would go safely.

My van has an external power point (which i think is pretty standard). I use toaster, kettle, frypan, drill from this piont. I'm standing on the ground when using them, therefore a path to earth

jimricho · Guru

oldtrack123 wrote:

Spell check often finds them ,but not always
Peter

-- Edited by oldtrack123 on Tuesday 25th of December 2012 10:50:15 PM

Yew will knot find any errors in this post width yore spell cheque because their aunt any!

oldtrack123 · Guru

Hi Big Gorilla

thanks for a good simple explanation ,which shows the importance of having a low resisrance, correctly WIRED earthing return system right back to the supply point.

IN fac,t the VAN camper trailer ,Motor home etc should not be deliberately connected to the earth we stand on ,by any other means than that approved & tested WIRED cabling

Incidental contact with the ground by stabilser legs does not count as they do not form an effective earth for electrical protection purposes

BUT a deliberate connection , by an earth stake or connection of the van to another earthed structure, including water pipes should not be done,

"It is neither recommended or required"

It serves no useful purpose & can actually introduce problems

More is not always better

Peter

pricey43 · Guru

Another point to consider is that a 15 amp lead will not pass and be tagged unless it has the plastic rim on the end attached to the caravan. The caravan therefore needs an inlet point which accepts this. Despite our van being only 6 months old the inlet does not have this provision. This is something we will take up with the manufacturer next service time.

PeterD · Guru

Nomad246 wrote:
PeterD, In your rush to provide an overview of the construction and operation of an ELCB you have overlooked a critical piece of this potential situation.
As in your summary "It does not matter whether the fault current flows through the earth wire or direct to ground."
Knowing that a caravan sits on rubber tyres, and possibly has no other confirmed and permenate current path to ground, a lead with good earth is the only path where the fault current would go safely.
OldTrack123 was on to it clarifying it as a high resistance earth and earlier as bad earth continuity.
Caravans and motorhomes are constructed in a way that is (electrically) above ground, hence my statement that normal operation of safety devices could be affected.

Nomad, If the van was perfectly insulated, you came in contact with the active conductor or a metallic appliance with a fault and you did not trip the ECLB then what is the problem. If you did not trip the ECLB then you would not have drawn enough current through your body to harm you. After look at all those linesmen working on live open wire mains supplies. They don't get electrocuted as they too are insulated from earth.

On the other hand, if there was enough current drawn via any capacitive coupling to earth to harm you then there would be enough unballance in the current through the ECLB to trip it.

Either way you would be safe, so what's your problem?

Nomad246 · Senior Member

The one and only point of my original post was to encourage people to be safe with portable power on extension leads.

I've seen "if" from one member,,, I've seen "metal on maybe wet wood blocks" from another member, both are stupid when you see the good argument from others on the requirement of having a properly functioning extension lead (including earthing) to provide the required safe outcomes.

I applaude Big Gorilla for offering his talents and qualified expertise to test leads of others, I'm of the same mind. It's all about safety.

My original post was about safety ,,, not about spell checks, correct circuit explanationation of an ELCB, nor character assassination, or who's up their own arse.

Let's test the leads to make sure they are safe

Cheers