Safety Recall

** Hi,

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

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" 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

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

Rheilly

Reply to
Rheilly Phoull

** 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

Reply to
Phil Allison

e

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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.

Reply to
kreed

"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

Reply to
Phil Allison

amples.

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.

Reply to
kreed

"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

Reply to
Phil Allison

Phil Allison presented the following explanation :

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.
Reply to
John G

kreed Inscribed thus:

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.
Reply to
Baron

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
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Reply to
Adrian Jansen

"Baron"

** 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

Reply to
Phil Allison

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

>
Reply to
terryc

Adrian Jansen Inscribed thus:

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.
Reply to
Baron

Phil Allison Inscribed thus:

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.
Reply to
Baron

terryc Inscribed thus:

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.
Reply to
Baron

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.

Reply to
terryc

terryc Inscribed thus:

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.

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.
Reply to
Baron

"Baron" Phil Allison

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

... Phil

Reply to
Phil Allison

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.

Reply to
JW

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.

Reply to
kreed

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