AFCI Breakers

[GoldDigger]

I almost hate to ask this, how much would a “custom arc signature generator” cost for each manufacturer?

Test equipment is essential if you’re going to guarantee your work. You wouldn’t be trading here without it.

OK I’ve got my tin hat on, let the onslaught begin ;-)

You would have to ask the manufacturer, since nobody knows what arc signatures they need.

I suppose you could do it with a broadband RF transmitter with high frequency amplitude and frequency modulation capability and a programmable signal generator

 

[mbrooke]

I agree with most of your points until we get to this.



No amount of new laws, codes or standards will ensure EGC continuity.

An area that has long had requirements for EGC connected metal frames still had deaths resulting from broken EGCs. I am talking about commercial kitchens.

The GFCI is a good step in trying to address those types of issues. In expensive proven technology.

I also have an even more inexpensive and just as proven technology for broken ground pins!

 

[Dennis Alwon]

Unless you have seen the electrons moving in and out of the processor inside of the AFCI, you have no idea why it tripped, and neither does anyone else. AFCI's are not like vehicles where we can plug a diagnostic computer into the car and find out exactly what is going wrong, and go to the root source of the problem. Much AFCI related troubleshooting is pure guess work and chasing one's tail, as we've seen many stories of that over the years.

This is not true. Cutler Hammer and I believe Siemens have AFCI breakers that do diagnostics. I will agree that many afci devices trip because of the gfci but as I stated I have had the GE trip-- it was a paddle fan. I used a different generation afci and everything worked fine.

 

[iwire]

I also have an even more inexpensive and just as proven technology for broken ground pins!

Great.

Do you have one for broken cords?

 

[mbrooke]

Great.

Do you have one for broken cords?

I dont think the objective of the NEC is to cover cords that are part of a UL listed appliance.

 

[mbrooke]

This is not true. Cutler Hammer and I believe Siemens have AFCI breakers that do diagnostics. I will agree that many afci devices trip because of the gfci but as I stated I have had the GE trip-- it was a paddle fan. I used a different generation afci and everything worked fine.

So you admit the GE AFCI could not differentiate between a dangerous arcing waveform and a normal the current waveform from the paddle fan?


Yes AFCIs exist with diagnostic abilities, but they dont get any deeper than ground fault, series fault, parallel fault. The arcing signature itself is still a mystery.

 

[Dennis Alwon]

So you admit the GE AFCI could not differentiate between a dangerous arcing waveform and a normal the current waveform from the paddle fan?


Yes AFCIs exist with diagnostic abilities, but they dont get any deeper than ground fault, series fault, parallel fault. The arcing signature itself is still a mystery.

I agree that the afci technology has to constantly readjust and somehow try and deal with every scenario out there. IMO, this is an almost impossible task so yes there are faults that should not occur.

 

[mbrooke]

I agree that the afci technology has to constantly readjust and somehow try and deal with every scenario out there. IMO, this is an almost impossible task so yes there are faults that should not occur.

Your opinion is not only correct, but the tip of the iceburg. The amount of electronics used in AFCIs is not enough and way to primitive to accurately differentiate between normal and abnormal arcs (assuming arcing is even a major concern at 120 volts). Arc logic used in medium voltage (2.4kv to 34.5kv) feeder breakers and line reclosers is thousands of times more detailed using mathematical morphology based oscilliogrphy analysis to accurately interpret waveforms.

Google "high impedance fault detection" This concept uses arc analysis where conventional relays can not sense low current fault such as a downed wire on dry grass or asphalt.

 

[Tony S]

Great.

Do you have one for broken cords?

For industrial yes there are. Our company used “earth (ground) proving outlets” before RCD/GFCI’s came in to common use.
If I remember right they are made by a company called Harvey Hubbel (American I do believe). They are still available.

You think AFCI’s are unreliable, try one of them. We worked to the mines and quarries act not BS7671 and had to use the damn things. If one was reported faulty you took a hammer with you.

 

[mbrooke]

For industrial yes there are. Our company used “earth (ground) proving outlets” before RCD/GFCI’s came in to common use.
If I remember right they are made by a company called Harvey Hubbel (American I do believe). They are still available.

You think AFCI’s are unreliable, try one of them. We worked to the mines and quarries act not BS7671 and had to use the damn things. If one was reported faulty you took a hammer with you.

Are they still required now that RCDs came about?

 

[don_resqcapt19]

I agree that the afci technology has to constantly readjust and somehow try and deal with every scenario out there. IMO, this is an almost impossible task so yes there are faults that should not occur.

A very good reason why AFCIs should not be forced on us by the code.

 

[Tony S]

Are they still required now that RCDs came about?

They were for certain types of equipment up until I retired. I don’t know which of my old tool chests I should even start looking for the regs.

 

[peter d]

2X

Well Said Peter D




Don

Me too. I feel the same way.

I'm glad I'm not the only one. The sad reality is that Bryan's comments pretty much confirm what we already know - the manufacturers do not care on iota about any opposing viewpoint to AFCI's and will just keep pushing forward with them. In other words, "Don't confuse me with facts because my mind is already made up." Not that my trust of AFCI's and the NEC could get any worse right now, but his "Get on board or get out of the way" comment put the final nail in the coffin.

 

[peter d]

It was Peter’s comment that prompted this.

In a way I find it funny but at the same time very sad.
A US based electrician should have faith in the NEC, just the same as my fellow electricians and I should have with the UK’s IET. Both organisations have gone off course, driven by inaccurate (downright biased) information. In both cases the manufacturers seem to have a considerable say in matters. But I’m sure their input is totally unbiased.

My interest and my worry is the UK picks up on AFCI’s. At the moment they would have a major hurdle as there is no set test procedure for an installed unit.

Hopefully you will never have to deal with such a horror as you have a good system in place already. But, with manufacturer influence, you never know. You have Schneider, Siemens, GE and Eaton to deal with just as we do.

 

[Tony S]

You have Schneider, Siemens, GE and Eaton to deal with just as we do.

and they have their collective fingers in the pie.

 

[mbrooke]

and they have their collective fingers in the pie.

They certainly do :rant:




http://w3.siemens.com/powerdistribu.../pages/optimum-protection-thanks-to-afdd.aspx

 

[peter d]

They certainly do :rant:




http://w3.siemens.com/powerdistribu.../pages/optimum-protection-thanks-to-afdd.aspx

Wow, that's just plain terrible. Looks like the poison has crossed the ocean now.

 

[Tony S]

They certainly do :rant:




http://w3.siemens.com/powerdistribu.../pages/optimum-protection-thanks-to-afdd.aspx

IEC?

Try again

 

[romex jockey]

They might gain validity , if the exact testing methods utilized were made public

For instance, they became 'combination' '08 NEC , meaning series parallel arc detection

All we have is some cotton test

Does anyone have the specific procedure from UL's cotton test?

~RJ~

 

[Tony S]

As a comparison, we now apparently have spontaneously combusting domestic DB’s. I’ve never seen one in 40 years. I tried to set fire to a redundant DB with a gas torch, it went a strange brown colour, no flames.

The IET have issued and edict that as of 01/01/16 all new domestic DB’s should be of metal construction. Only the UK has had this thrust on them. The IET chose to totally ignore the CE standard for plastic enclosures DIN IEC 60695-2-1015 (960 degree C glow wire flammability test).

This only applies to domestic properties, commercial and industrial units are exempt.



You’re allowed one guess who were major contributors to the recommendation committees findings.



I’ll give a clue to help you £$