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When is a spark an arc? OR - When is an arc a spark?

Just watched some chap on the E5 youtube channel visiting Eaton in Austria. Eaton AFDDs have been something of a subject of ridicule in youtubeland, with various respected electrical content providers demonstrating through various real-world means that they don't function. So, off this chap goes to Eaton's HQ in Vienna where they provide him with a aluminium case full of test kit, complete with the Eaton logo and fitted out with various Eaton devices inside.

One of the devices is the Eaton AFFDD which has famously failed to operate on numerous youtube video presentations.

Of course, it trips when tested with their own test kit. After all, no point in trying to sell something which isn't really needed unless you can demonstrate that it actually works, so Eaton helpfully provides the 'right' arc signature so that the device can trip on command in front of all those cynical doubters.

Apparently, all those heath robinson youtubers have been getting it wrong because they have unhelpfully been simulating real world arcing events which these devices won't actually pick up. You see, according to the 'experts' you need an arc instead of a spark to trip the device! What the hell is the difference?

Oh how I laughed! Is this how far they'll go to flog you some old tat you don't really need?

Just how many different arcs and sparks are there out there? Has anyone told David Attenborough of all these new species to explore?

Feel free to jump in!

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0 Former Community Member over 5 years ago

mapj1:

That is interesting to know, thought it simply transfers the question to be asking if the EN standard 'arc' fault waveform actually represents the sort of current waveform you would get with a real fault of the kind you should disconnect.

This is very different to testing RCDs where we are all agreed that the test rig and the faults are similar, here I suspect there are real loads that look like arc faults, and arc faults that have signatures nothing like the standard test waveform.

With modern electronics it is possible to interrupt and reconnect in almost arbitrary speed and precision, so making an AFD tester that spits out a very complex set of test waveforms is a technically trivial matter - the hard work is agreeing what the waveforms should be.

I'm not sold on the idea myself, I thing we are some way from a useful item.

It's not so much a standard arc waveform but a description of the criteria that need to be met, & a standard test "wire" to simulate the fault.

Along side their development rig Eaton had racks of different products which they had been using to develop the firmware, as in to recognise their arc signature as friendly arc's Siemens have been doing the same.

I think the issue with developing a standard test device is that the specifics of the detection mechanism, i.e. how the hardware and firmware respond the same to the same stimuli, or just give the same end result.

As far as RCD's go, with all the new non linear loads that have developed and the RCD's that have been developed to identify those leakages and react to them, are our "standard" RCD tests adequate any longer?...

As far as "some way from a useful item" goes, I'm not going to argue, especially when you think that the minimum current threshold for detection is around 2.5A, but, being worked on by the manufacturers to reduce it I believe.
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0 Former Community Member over 5 years ago

mapj1:

That is interesting to know, thought it simply transfers the question to be asking if the EN standard 'arc' fault waveform actually represents the sort of current waveform you would get with a real fault of the kind you should disconnect.

This is very different to testing RCDs where we are all agreed that the test rig and the faults are similar, here I suspect there are real loads that look like arc faults, and arc faults that have signatures nothing like the standard test waveform.

With modern electronics it is possible to interrupt and reconnect in almost arbitrary speed and precision, so making an AFD tester that spits out a very complex set of test waveforms is a technically trivial matter - the hard work is agreeing what the waveforms should be.

I'm not sold on the idea myself, I thing we are some way from a useful item.

It's not so much a standard arc waveform but a description of the criteria that need to be met, & a standard test "wire" to simulate the fault.

Along side their development rig Eaton had racks of different products which they had been using to develop the firmware, as in to recognise their arc signature as friendly arc's Siemens have been doing the same.

I think the issue with developing a standard test device is that the specifics of the detection mechanism, i.e. how the hardware and firmware respond the same to the same stimuli, or just give the same end result.

As far as RCD's go, with all the new non linear loads that have developed and the RCD's that have been developed to identify those leakages and react to them, are our "standard" RCD tests adequate any longer?...

As far as "some way from a useful item" goes, I'm not going to argue, especially when you think that the minimum current threshold for detection is around 2.5A, but, being worked on by the manufacturers to reduce it I believe.
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When is a spark an arc? OR - When is an arc a spark?

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