Safety Recall

[Phil Allison]

** Hi,

came across this warning on the Yamaha Music web site recently:

http://au.yamaha.com/en/news_events/proaudio/product-recall-2011/

" Hazard Due to the defect products can cause death or injury to the user "

Sounds pretty serious.

But how can an AC plug be wired wrong and the unit still work and not trip
ELCBs ??



.... Phil

 

[Rheilly Phoull]

On 12/17/2011 6:09 AM, Phil Allison wrote:

** Hi,

came across this warning on the Yamaha Music web site recently:

http://au.yamaha.com/en/news_events/proaudio/product-recall-2011/

" Hazard Due to the defect products can cause death or injury to the user"

Sounds pretty serious.

But how can an AC plug be wired wrong and the unit still work and not trip
ELCBs ??



... Phil

Well there are still some older homes without the protection, perhaps
it's to cover all bases ??

Rheilly

 

[Phil Allison]

"Rheilly Phoull"
Phil Allison wrote:

** Hi,

came across this warning on the Yamaha Music web site recently:

http://au.yamaha.com/en/news_events/proaudio/product-recall-2011/

" Hazard Due to the defect products can cause death or injury to the
user"

Sounds pretty serious.

But how can an AC plug be wired wrong and the unit still work and not
trip
ELCBs ??



Well there are still some older homes without the protection,

** All the products concerned are for professional / commercial use.

If they tripped ELCBs - owners would be unable to use them at all making
the re-call redundant.

Also note that some of the items ( the powered speakers ) have standard 3
pin IEC inlets.

None of the items are class 2 or double insulated, AFAIK.



.... Phil

 

[Phil Allison]

"kreed"

About the only scenario that comes to mind is the earth wire not being
connected,

** My initial thought - but that is very unlikely across all the examples.


though if some of the items have IEC inlets, then the wiring fault
might be in the unit itself and not the IEC cord.

** Has to be - but the notice says the plug needs rewiring.


Of course, they might have copped a bad batch
of IEC cords

** With what fault?

It cannot be neutral-earth swapped.

It is possible that they chopped the foreign plug off the (non-IEC)
cords, installed an Australian plug, and somoene messed up the job,


** Very unlikely and what is the actual mistake ????????



.... Phil

 

[kreed]

On Dec 17, 9:33 am, "Phil Allison" <phi...@tpg.com.au> wrote:

"Rheilly Phoull"









Phil Allison wrote:

** Hi,

came across this warning on the Yamaha Music web site recently:

http://au.yamaha.com/en/news_events/proaudio/product-recall-2011/

" Hazard  Due to the defect products can cause death or injury to the
user"

Sounds pretty serious.

But how can an AC plug be wired wrong and the unit still work and not
trip
ELCBs ??

Well there are still some older homes without the protection,

** All the products concerned are for professional / commercial use.

If they tripped ELCBs  -  owners would be unable to use them at all making
the re-call redundant.

Also note that some of the items ( the powered speakers ) have standard 3
pin IEC inlets.

None of the items are class 2 or double insulated, AFAIK.

...   Phil

About the only scenario that comes to mind is the earth wire not being
connected,

though if some of the items have IEC inlets, then the wiring fault
might be in the unit itself,
and not the IEC cord. Of course, they might have copped a bad batch
of IEC cords which could be
interesting if so, as they might end up being used on other devices.

It is possible that they chopped the foreign plug off the (non-IEC)
cords, installed an Australian plug, and somoene messed up the job,
though this doesn't sound viable on IEC inlet units compared to buying
in ready made cords, especially
with the prices that Yamaha would be able to get them for.

 

[Phil Allison]

"kreed"

I do see what you mean, 2 different types of cords, and there is a
recall on both types.

** No - there is a recall on the products.


Only faults I can think of that would be hazardous, but the gear would
still work would be no earth connection at the plug,


** You said that already.

or earth and neutral both connected to the neutral pin,

** Still trips ELCBs in a moment.


as it says "plug may have been wired incorrectly" and "rewire the
mains plug if faulty"

** Wrong to take that literally.

It was written by some moron in marketing you know.


The units could have come from China (or where ever they are made)
with the Australian plugs wired by hand there too.

** I have not seen a hand wired plug on anything from Asia in decades


If they didn't
have sufficient ready made cords, they may have hand wired a few plugs
onto existing ones to get the shipment ready to deadline.

** IEC leads are prescribed items, each component must be approved ( and
labelled with the approval code number) for use in Australia - you cannot
just dodgy one up from bits.

Moulded ones with Aussie plugs ( same as China) cost tiny amounts compared
to paying someone to modify one with the wrong plug.



.... Phil

 

[kreed]

On Dec 17, 9:55 am, "Phil Allison" <phi...@tpg.com.au> wrote:

"kreed"

About the only scenario that comes to mind is the earth wire not being
connected,

**  My initial thought -  but that is very unlikely across all the examples.

though if some of the items have IEC inlets, then the wiring fault
might be in the unit itself and not the IEC cord.

** Has to be - but the notice says the plug needs rewiring.

Of course, they might have copped a bad batch
of IEC cords

**  With what fault?

It cannot be neutral-earth swapped.

It is possible that they chopped the foreign plug off the (non-IEC)
cords, installed an Australian plug, and somoene messed up the job,

** Very unlikely and what is the actual mistake ????????

...  Phil

I do see what you mean, 2 different types of cords, and there is a
recall on both types.

Only faults I can think of that would be hazardous, but the gear would
still work would be

no earth connection at the plug, or
earth and neutral both connected to the neutral pin,

as it says "plug may have been wired incorrectly" and "rewire the
mains plug if faulty"




The units could have come from China (or where ever they are made)
with the Australian plugs wired by hand there too. If they didn't
have sufficient ready made cords, they may have hand wired a few plugs
onto existing ones to get the shipment ready to deadline.

They wouldn't be moulded - if the technician will "rewire the mains
plug if faulty".








Finally another fault I found recently. When cutting an IEC lead to
hard wire it into a terminal block inside a cabinet, found that there
was no earth wire for about 8" inside the cord, but just a hole next
to the other 2 wires where it should have been. IT could not have
been removed at any stage after manufacture, as the outer insulation
was intact with no cuts or other damage visible. Also it was missing
in the middle of the cable, not at an end.


Were lucky to have cut it in the right place or this might not have
ever been discovered. I have never in nearly 40 years ever seen this
before in any 3 core flex cable that I have worked with.

This was a Japanese made cord probably of 1980s vintage, very light
grey in colour.

 

[John G]

Phil Allison presented the following explanation :

"kreed"

I do see what you mean, 2 different types of cords, and there is a
recall on both types.

** No - there is a recall on the products.


Only faults I can think of that would be hazardous, but the gear would
still work would be no earth connection at the plug,


** You said that already.

or earth and neutral both connected to the neutral pin,

** Still trips ELCBs in a moment.


as it says "plug may have been wired incorrectly" and "rewire the
mains plug if faulty"

** Wrong to take that literally.

It was written by some moron in marketing you know.


The units could have come from China (or where ever they are made)
with the Australian plugs wired by hand there too.

** I have not seen a hand wired plug on anything from Asia in decades


If they didn't
have sufficient ready made cords, they may have hand wired a few plugs
onto existing ones to get the shipment ready to deadline.

** IEC leads are prescribed items, each component must be approved ( and
labelled with the approval code number) for use in Australia - you cannot
just dodgy one up from bits.

Moulded ones with Aussie plugs ( same as China) cost tiny amounts compared to
paying someone to modify one with the wrong plug.

... Phil

I thought hand wired plugs were not permitted on Original supply power
cords for many years now.

However a VERY large computer company I worked for long ago had a few
IEC leads, supplied by a cable and tyre company, misswired but they
seemed to work (can't remmeber just what was wrong except the case was
live)
Thousands of cords were tested to find a very small number wrong.

I know GFCIs or what ever, are now required in the domestic situation,
but are they required or even effective in large office situations.

--
John G.

 

[Baron]

kreed Inscribed thus:

Finally another fault I found recently. When cutting an IEC lead to
hard wire it into a terminal block inside a cabinet, found that there
was no earth wire for about 8" inside the cord, but just a hole next
to the other 2 wires where it should have been. IT could not have
been removed at any stage after manufacture, as the outer insulation
was intact with no cuts or other damage visible. Also it was missing
in the middle of the cable, not at an end.


Were lucky to have cut it in the right place or this might not have
ever been discovered. I have never in nearly 40 years ever seen this
before in any 3 core flex cable that I have worked with.

This was a Japanese made cord probably of 1980s vintage, very light
grey in colour.

Odd this should come up ! I've just replaced the mains lead on an 800W
bench circular saw. Intermittent fuse blowing. Turns out that the
mains lead has had the live and earth wires migrate through the
insulation where the lead had been folded when the saw was originally
packaged.

I admit that I had to cut the cable in short chunks to actually find
where it was shorting. At each bend in the cable the two conductors
had migrated through the insulation.

I've put a new mains lead on and all is fine now. The original lead was
very hard, stiff plastic, not soft and flexible like you would expect.
I also found that the blue insulation was bonded with the outer jacket
and the brown live insulation, making it impossible to strip the
insulation from just one wire without damaging the others.

--
Best Regards:
Baron.

 

[Adrian Jansen]

On 18/12/2011 6:01 AM, Baron wrote:

Odd this should come up ! I've just replaced the mains lead on an 800W
bench circular saw. Intermittent fuse blowing. Turns out that the
mains lead has had the live and earth wires migrate through the
insulation where the lead had been folded when the saw was originally
packaged.

I admit that I had to cut the cable in short chunks to actually find
where it was shorting. At each bend in the cable the two conductors
had migrated through the insulation.

I've put a new mains lead on and all is fine now. The original lead was
very hard, stiff plastic, not soft and flexible like you would expect.
I also found that the blue insulation was bonded with the outer jacket
and the brown live insulation, making it impossible to strip the
insulation from just one wire without damaging the others.

Sounds like it was subjected to enough heat to partially melt both the

inner insulation and the outer jacket. Poor quality insulation, with a
low melting point ?

--
Regards,

Adrian Jansen adrianjansen at internode dot on dot net
Note reply address is invalid, convert address above to machine form.

 

[Phil Allison]

"Baron"

I've just replaced the mains lead on an 800W
bench circular saw. Intermittent fuse blowing. Turns out that the
mains lead has had the live and earth wires migrate through the
insulation where the lead had been folded when the saw was originally
packaged.

** Though it sounds frightening, the only likely result of the conductors
inside an AC power cable coming into contact is fuse blowing, circuit
breaker tripping or ELCB tripping.

After all, that is what they are there for....


..... Phil

 

[terryc]

Adrian Jansen wrote:

Sounds like it was subjected to enough heat to partially melt both the
inner insulation and the outer jacket. Poor quality insulation, with a
low melting point ?

Folded too soon after construction?
Or as you suggest, the cable just wasn't up to the job of carrying the
current.
>

 

[Baron]

Adrian Jansen Inscribed thus:

On 18/12/2011 6:01 AM, Baron wrote:


Odd this should come up ! I've just replaced the mains lead on an
800W
bench circular saw. Intermittent fuse blowing. Turns out that the
mains lead has had the live and earth wires migrate through the
insulation where the lead had been folded when the saw was originally
packaged.

I admit that I had to cut the cable in short chunks to actually find
where it was shorting. At each bend in the cable the two conductors
had migrated through the insulation.

I've put a new mains lead on and all is fine now. The original lead
was
very hard, stiff plastic, not soft and flexible like you would
expect. I also found that the blue insulation was bonded with the
outer jacket and the brown live insulation, making it impossible to
strip the insulation from just one wire without damaging the others.

Sounds like it was subjected to enough heat to partially melt both the
inner insulation and the outer jacket. Poor quality insulation, with a
low melting point ?

Yes I completely agree with you !
Trouble is, you don't find out there is a problem until you have a
problem. If you know what I mean...

--
Best Regards:
Baron.

 

[Baron]

Phil Allison Inscribed thus:

"Baron"

I've just replaced the mains lead on an 800W
bench circular saw. Intermittent fuse blowing. Turns out that the
mains lead has had the live and earth wires migrate through the
insulation where the lead had been folded when the saw was originally
packaged.


** Though it sounds frightening, the only likely result of the
conductors inside an AC power cable coming into contact is fuse
blowing, circuit breaker tripping or ELCB tripping.

After all, that is what they are there for....


.... Phil

I do agree ! The question that springs to mind, is what if the earth
conductor was OC or partially missing. There is/was the risk that the
whole saw could have become live. Also with a moulded on plug there
wouldn't be any guarantee that the insulation wasn't compromised
inside.

--
Best Regards:
Baron.

 

[Baron]

terryc Inscribed thus:

Adrian Jansen wrote:

Sounds like it was subjected to enough heat to partially melt both
the inner insulation and the outer jacket. Poor quality insulation,
with a low melting point ?

Folded too soon after construction?
Or as you suggest, the cable just wasn't up to the job of carrying the
current.

The cable has been binned and replaced now.

A point that occurs to me is, since the conductors are welded to the
pins inside the molded plug, could the wire itself have become the
return path for the welding current. If so that could explain the way
the insulation was bonded to the jacket and other wires. Possibly the
wires could have become hot enough to cause the migration seen.

Either way its a potential hazard that would be completely hidden from a
user until it caused a problem.

--
Best Regards:
Baron.

 

[terryc]

Baron wrote:

Sounds like it was subjected to enough heat to partially melt both the
inner insulation and the outer jacket. Poor quality insulation, with a
low melting point ?


Yes I completely agree with you !
Trouble is, you don't find out there is a problem until you have a
problem. If you know what I mean...

Unlesss you just happen to pick the cable up at the right moment and
realise there is a hot spot.

BTDT and snip snip nip to the copper recycling bin. Most you just smell
or wonder where that smoke is coming from.

 

[Baron]

terryc Inscribed thus:

Baron wrote:

Sounds like it was subjected to enough heat to partially melt both
the inner insulation and the outer jacket. Poor quality insulation,
with a low melting point ?


Yes I completely agree with you !
Trouble is, you don't find out there is a problem until you have a
problem. If you know what I mean...

Unlesss you just happen to pick the cable up at the right moment and
realise there is a hot spot.

In this case the first sign of any problem was a blown fuse ! Following
replacement some time passed before the fuse blew again. Each time the
machine worked satisfactorily following fuse replacement. It was only
the last time the fuse blew almost immediately that it was realised
that flexing the cable was the culprit.

BTDT and snip snip nip to the copper recycling bin. Most you just
smell or wonder where that smoke is coming from.

Yes it did end up in the scrap cable bin. I don't recall that there was
any smoke or oder at all.

--
Best Regards:
Baron.

 

[Phil Allison]

"Baron"
Phil Allison

** Though it sounds frightening, the only likely result of the
conductors inside an AC power cable coming into contact is fuse
blowing, circuit breaker tripping or ELCB tripping.

After all, that is what they are there for....


I do agree ! The question that springs to mind, is what if the earth
conductor was OC or partially missing. There is/was the risk that the
whole saw could have become live.

** That is what ELCBs are for......


.... Phil

 

[JW]

On Fri, 16 Dec 2011 16:55:46 -0800 (PST) kreed <kenreed1999@gmail.com>
wrote in Message id:
<953d782e-6c75-45e2-b441-7f3dbade5b81@t36g2000prj.googlegroups.com>:

Finally another fault I found recently. When cutting an IEC lead to
hard wire it into a terminal block inside a cabinet, found that there
was no earth wire for about 8" inside the cord, but just a hole next
to the other 2 wires where it should have been. IT could not have
been removed at any stage after manufacture, as the outer insulation
was intact with no cuts or other damage visible. Also it was missing
in the middle of the cable, not at an end.

A few months ago I cut off the end of an IEC cord to put spade lugs on it
for testing a 6031A power supply. Imagine my surprise when the inside
conductors were 26ga wire. The cords had a 10A 250V rating on it and a UL
stamp, likely forged.

 

[kreed]

On Dec 19, 8:25 pm, JW <n...@dev.null> wrote:

On Fri, 16 Dec 2011 16:55:46 -0800 (PST) kreed <kenreed1...@gmail.com
wrote in Message id:
953d782e-6c75-45e2-b441-7f3dbade5...@t36g2000prj.googlegroups.com>:



Finally another fault I found recently.   When cutting an IEC lead to
hard wire it into a terminal block inside a cabinet, found that there
was no earth wire for about 8" inside the cord, but just a hole next
to the other 2 wires where it should have been.  IT could not have
been removed at any stage after manufacture, as the outer insulation
was intact with no cuts or other damage visible.  Also it was missing
in the middle of the cable, not at an end.

A few months ago I cut off the end of an IEC cord to put spade lugs on it
for testing a 6031A power supply. Imagine my surprise when the inside
conductors were 26ga wire. The cords had a 10A 250V rating on it and a UL
stamp, likely forged.

I think it is a good idea to do the "electric jug test" on these
things. The cable will heat up
real quick in this case, and can be easily spotted as insufficient
cross sectional area of conductor.