Power cables

oldtrack123 · Guru

Power cables

oldtrack123 · Guru

brickies wrote:
Well maybe Robo24 has been putting an 10 amp lead into a 15 amp power point at the caravan park

Hi

That, while unwise[ in fact could lead to a fire] would not be the reason for the plug falling out

The pins are still the same thickness, possibly the outlet's contacts' had lost tension

PeterQ

oldtrack123 · Guru

Aus-Kiwi wrote:
oldtrack123 wrote:
Aus-Kiwi wrote:
know what's done .. But can't recommend .. Wire size on some of these extension cables is just enough..
I bought twin and earth from Bunnings asked for 2.5mm I tell you it's NOT 2.5 mm ..
20 Amp yes ..

Hi
Perhaps tell us what size it is???
AS/NZS3199 Approved cables for 20A start @ 2.5mmx for length up to 30M for general use
or do as I suggested in above post
They can be penalised for selling non approved extension leads!!

PeterQ
As said twin and earth .. Not flex.. Wired up my two post hoist..

HI

You still did not say what size the cable was?

Or why you could not see it was not 2.5x

Where you carrying out licensed electrical work??

in any case not relevant, nothing to do with extension leads

PeterQ

Aus-Kiwi · Guru

oldtrack123 wrote:
Aus-Kiwi wrote:
The light circuit on most homes may not nessesary be through an rcd..
There's no fault through active and neutral either ..
{ Quote]"There's no fault through active and neutral either .."[end quote]
Just what do you mean??

But just like the Insulation deaths
Faults/shocks to earth can occur
That has changed the Rules
RCDs are now required on lighting circuits
The Standards were changed once a problem was recognised
PeterQ

PeterQ

-- Edited by oldtrack123 on Tuesday 9th of June 2015 11:39:06 AM

These where old buildings when your talking about the insulation deaths..

Can still get an elect shock between active and neutral . The RCD won't trip..

Btw the hoist is hard wired. Switch etc is on frame ..

oldtrack123 · Guru

Aus-Kiwi wrote:
[1] These where old buildings when your talking about the insulation deaths..
[2]Can still get an elect shock between active and neutral . The RCD won't trip..
Btw the hoist is hard wired. Switch etc is on frame ..

[1]Why would they only be "old" buildings???

[2]Yes, and there is no means of protection if one makes contact between ACTIVE wires

PeterQ

Aus-Kiwi · Guru

oldtrack123 wrote:
Aus-Kiwi wrote:
[1] These where old buildings when your talking about the insulation deaths..
[2]Can still get an elect shock between active and neutral . The RCD won't trip..
Btw the hoist is hard wired. Switch etc is on frame ..

[1]Why would they only be "old" buildings???
[2]Yes, and there is no means of protection if one makes contact between ACTIVE wires
PeterQ

Older buildings didn't have RCDs .. Only recent rules have changed to include all circuits on new homes..

Old VIR wire in steel conduit is bloody dangerous electrically to say nothing about asbestos on top..

oldtrack123 · Guru

Aus-Kiwi wrote:
Older buildings didn't have RCDs .. Only recent rules have changed to include all circuits on new homes..
[a]Old VIR wire in steel conduit is bloody dangerous electrically to say nothing about asbestos on top..

Hi

[a] They would be VERY, very old buildings if they had VIR & split steel conduit

Generally before about 1945

However such buildings would be much safer as far as the insulation problem where concerned, which was due to STAPLES being driven into unprotected TPS cables

A bit hard to drive a staple through even thin split steel conduit biggrin

PeterQ

Aus-Kiwi · Guru

Way off subject but yes .. The thing is the steel conduit is an earth and even if it wasn't it can become live real easy..
I would say if down lights have been fitted ? There's some bodgy work done .. Crawling around in roof area is not a safe place ..
Plus it doesn't take much to keep clearance around down lights .. Obviously people unqualified or NOT trained to do this work ...
What the wiring rules for houses is not the same for extension leads . The leads are thinner wire ...
Just be aware not to over load lead or leave rolled up when in use ... Particularly if it has wire type fuse...

Ontos45 · Guru

Electricity/ cables and the dangers of leaving it coiled up and plugged in?

First of all a coiled cable will not produce any electromagnetic field as long as no current flows on the cable. So even if its plugged-in but no electrical equipment is drawing power from it then no current flows.

Secondly, most commercial cables that come with your electrical equipment or even on commercial extension plugs are always duplex and/or triplex. That means two to three insulated cables bundled together. This is of course a safety feature against cable coiling. You see a single cable being coiled and induced with current flow will produce a large electromagnetic field. But bundle that single cable with another cable that is of the opposite polarity and no field will be produced as the two will cancel out.

You can test this fact with the use of a clamp ammeter. Plug your electric fan or any equipment that has a duplex power cord then switch it on. Measure the current in the power cord with a clamp ammeter and you will see that your current will be zero. But isolate a single wire on the power cord and your ammeter will have a non-zero reading.

From Yahoo7 answers.

(I've always used my cables un-coiled, not rolled up even on a drum)

oldtrack123 · Guru

Hi
Hmmm, some info gets even more confusing
Peter
You are correct
When the feed & return are run in close proximity to each other [As in multi core cables ] there is NIL magnetic/inductive effect
That simple means voltage drop will only be due to cable resistance & current flow, with no inductive losses & no heat generated due to that.
BUT cable heating due to IxIxR will still occur
ALL cables no matter if single or multi core should be unrolled for use
They are rated for use in free air that simply means air cooling over every mm of their length
If they do not have free air cooling they must be derated.

In the days of steel conduit &still where metal pipes,tubing or sheathing is still in use the sheathing SHALL have continuity over its full length & be solidly bonded to the EARTHING system
The metal conduit would only impose a risk if that continuity has been destroyed

In older houses with failing VIR insulating, shorting to the conduit blows the fuses
Of course ,often some one just wires the fuse with heavier wire, resulting in holes being burnt through the thin steel conduit wall.

Regarding cable sizes
2.5mm x cable is 2.5mm x cable
2.5 mm x TPS as fixed wiring in open air is rated @20A
2.5 mm x flexible cable in open air is rated @20.A

What has to be taken into consideration is the LENGTH & VOLTAGE drop over that length
The cable size may have to be encreased to meet voltage drop limits
That is why factory made extension leads will have heavier cables for longer length than would be required just based on current[ AS specified in AS/NZS 3199]

PeterQ