ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
AreMetal Ladders Ever OK For Electrical Work?
by HotLine1. 01/22/18 07:31 PM
by twh. 01/22/18 05:06 PM
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 24 guests, and 12 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
AFCI for the foreigners... #43321
10/10/04 08:19 AM
10/10/04 08:19 AM
:andy:  Offline OP
Joined: Oct 2003
Posts: 289
Hey there,

would anyone try to answer me some Questions about AFCIs, as they aren't used here in Germany (only gfci).

What interests me mainly is

-How does the AFCI detect arcing? How is the current sensing done?
-How does it separate a light switch arc from a fault arc
-Does it work as it's promised? No trips on switches and plugging, but safe trips on fault arcs?

thanks very much

Work Gear for Electricians and the Trades
Re: AFCI for the foreigners... #43322
10/10/04 09:52 AM
10/10/04 09:52 AM
CharlieE  Offline
Joined: Apr 2004
Posts: 200
They work but not well yet. It takes 75 amperes before they will react unless it is a ground fault. In the case of a ground fault, they will trip at 30 to 50 milliamperes depending on who manufactured the device. They will not protect against a series arcing fault at all. IMHO the NEC was used to promote a new technology that did not perform as promised.

The next device is the combination type. The combination type will protect against series as well as parallel and ground faults. It will also protect extension cords that are plugged into the circuit. These devices are now developed and listed but they have no track record and are not even on the market. With all that said, the combination type will be required by the NEC on new construction starting January 1st, 2008 . . . HMMM. [Linked Image]

- - - - - - - - - - - - - - - - - - - - - - - - - - -
Charlie Eldridge, Indianapolis, Utility Power Guy

Charlie Eldridge, Indianapolis Utility Power Guy
Re: AFCI for the foreigners... #43323
10/10/04 10:58 AM
10/10/04 10:58 AM
:andy:  Offline OP
Joined: Oct 2003
Posts: 289
Alright, so it's a good idea but not technically mature yet....

So they do only trip at short circuit arcs, but not on contact problem arcs??

A 16 Amp breaker (standard for Schuko receptacles) here trips instantly at an 80A spike, so this could meet your 75A arc trip demand.

Re: AFCI for the foreigners... #43324
10/10/04 11:14 AM
10/10/04 11:14 AM
capt al  Offline
Joined: Jun 2004
Posts: 206
Norton, Ma USA
Charlie is right about new technology that does not perform as promised. Square D is now recalling AFCI breakers manufactured from 3/1/04 thur 9/23/04. Date codes CN DN EN FN GN HN JN. The breakers do not trip.

Re: AFCI for the foreigners... #43325
10/10/04 11:32 AM
10/10/04 11:32 AM
:andy:  Offline OP
Joined: Oct 2003
Posts: 289
that's bad...

so did i understand right, the breakers don't trip at a loose wirenut ect fault, but only on "real" short circuit faults?

thanks for your input [Linked Image]

If you are interested, that's a graphic trip diagram for european/german breakers:

time in seconds and minutes on the vertical, current multiplier on the horizontal

B, C and D show the trip characteristics. B Breakers are usual for normal homes and pretty fast. C and D (and K, not shown) are slower for bigger machines with high startup currents). As shown, above 5 seconds they all act the same.

You see that the 16A breaker will sure trip at a 80A spike (16A * 5).

The bottom text diagram shows Thermal tripping on the left and shortcirc tripping on the right.

For the B characteristics, the Breaker needs to stay on for > 1 hour at 1.13*Current, and needs to trip in <1h at 1.45*current.

Short circuit trip is given at 5*current faster than 0.1 secs.
at 3*current slower than 0.1 sec.

[This message has been edited by :andy: (edited 10-10-2004).]

Re: AFCI for the foreigners... #43326
10/10/04 04:30 PM
10/10/04 04:30 PM
pauluk  Offline
Joined: Aug 2001
Posts: 7,520
Norfolk, England

The following manufacturer's site gives an outline of how the AFCI is supposed to work:

There were many discussions here about the AFCI a year or two ago. You might find some points of interest in the following threads:

AFCI breakers

afci parallel series

AFCIs and series arcing faults

Re: AFCI for the foreigners... #43327
10/10/04 07:31 PM
10/10/04 07:31 PM
Trumpy  Offline

Joined: Jul 2002
Posts: 8,231
SI,New Zealand
Good call there mate!. [Linked Image]
I've also been wondering for some time as to what these devices do and how they work.
It's been mentioned that these devices detect arcing, saying that, would a vacuum cleaner using a brush-type motor (Universal) with a bad commutator or brushes, cause an AFCI to trip?.
Thanks for the links everyone, I'm learnin' fast!. [Linked Image]


2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman


Member Spotlight
Posts: 22
Joined: August 2009
Show All Member Profiles 
Top Posters(30 Days)
Admin 21
sparky 15
Potseal 15
Popular Topics(Views)
243,602 Are you busy
180,416 Re: Forum
170,873 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.062s Queries: 14 (0.014s) Memory: 0.9853 MB (Peak: 1.1383 MB) Zlib enabled. Server Time: 2018-01-23 21:55:01 UTC