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#15343 - 10/14/02 09:18 AM AFCI, GFCI, MCB...
C-H Offline


Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden

It seems as if the once so simple fuses in the fusebox aren't so simple anymore. First came the breaker with electromagnetic and thermal trip, then the ground fault circuit interrupter measuring current balance and now arc fault circuit interrupters with a microprocessor. Soon the "fuse box" will run Windows, crashing once a week...

Here's my question/idea: Are fully electronic breakers the future? Instead of having a thermal trip, it measures the current, checks the waveform and possible imbalance between the two wires. It will still have to have a magnetic tripping mechanism, of course.

I can think of two advantages of such a design:

1.) The overload protection doesn't depend on the number and load of the breakers next to it. No derating --> no need to put oversize breakers to avoid nuisance trips--> less risk of fire.

2.) Breaker discrimination is facilitated, since you can program a real trip curve, not just "oh, it will trip somewhere between three and five times the rated current"

If the price is right we could have GFI and perhaps AFI proctection on all branch circuits --> less risk of people killed by things like broken switches and receptables or poor wiring.

Does such a thing exist? Any opinions?

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#15344 - 10/14/02 01:11 PM Re: AFCI, GFCI, MCB...
pauluk Offline

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Interesting concept, but I suppose there's always the point that each extra level of complexity means something more which could fail to operate as intended. Some other threads here already contain many questions about the longevity of the GFI and AFCI.

Maybe a combined thermal-magnetic and microprocessor controlled breaker would be the ideal, the former acting as a backup, but I can't help feeling that this might be going just a bit too far.

Soon the "fuse box" will run Windows, crashing once a week...

Er, wouldn't it be more like once every five minutes?

#15345 - 10/14/02 02:32 PM Re: AFCI, GFCI, MCB...
Bjarney Offline

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
C-H, with the marketing buzzword "smart" everything, molded-case breakers may someday allow fault/overload/GF/AF capabilities enabled in firmware at manufacturing.

That would lead, of course, to pirate firmware to “soup up” {or cripple} devices’ “high-performance” features.

#15346 - 10/15/02 05:30 AM Re: AFCI, GFCI, MCB...
pauluk Offline

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
"The appliance you are using has performed an illegal operation and power to this circuit will be removed. Please remove all appliances, re-install your electrical service, and try again. If the problem persists, please upgrade to Windows AFCI version 34.9"

Sorry.... Couldn't resist adding that one...

#15347 - 10/15/02 05:54 AM Re: AFCI, GFCI, MCB...
Texas_Ranger Offline

Registered: 12/17/01
Posts: 2332
Loc: Vienna, Austria
And over time your panel will mysteriously fill up and finally crash. Then you'll have to completely take apart the panel and carefully reinstall every component. Then it'll work for some time until the cycle starts once again.

#15348 - 10/15/02 06:27 AM Re: AFCI, GFCI, MCB...
Trainwire Offline

Registered: 03/15/02
Posts: 364
Loc: Strasburg,PA,USA
oof, what would the spam look like?

let's not go there

#15349 - 10/19/02 08:30 PM Re: AFCI, GFCI, MCB...
Trumpy Offline


Registered: 07/05/02
Posts: 8532
Loc: SI,New Zealand
Interesting how you can have a micro-processor in a switchboard,does this device take into account the Harmonic component of
our pretty-much common problem of non-linear
loads(computers,VSD's, etc)
Let's face it, these days if you're not young, you're old - Red Green grin


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