Comments on: Arc Fault Detection Devices

By: Tomi Engdahl

Tomi Engdahl — Sun, 19 Jul 2026 13:36:33 +0000

Under UL 943, a Class A GFCI designed for personal protection must trip when a ground fault between 4 mA and 6 mA is detected.
The US chooses this ultra-sensitive window because it sits right below the “let-go” threshold.
The US philosophy is: Stop the shock before the user is physically paralyzed by the current.

A current of 30\text{ mA} passing through the human body can be lethal if it is sustained for several seconds.
However, modern European 30 mA RCDs are strictly required to disconnect the circuit incredibly fast—typically in under 40 milliseconds at full rated current.
At 40 milliseconds, a 30\text{ mA} current is well inside the “Zone AC-3″ of the IEC safety curve. In this zone, you will feel a nasty, painful shock and muscle contraction, but the risk of your heart going into fatal ventricular fibrillation is practically zero. Europe’s philosophy isn’t “prevent you from feeling a shock,” it is “prevent the shock from stopping your heart before the breaker clears.”

By: Tomi Engdahl

Tomi Engdahl — Sun, 19 Jul 2026 06:55:58 +0000

Eric Fowler In Europe, Ground Fault Circuit Interrupters (GFCIs) are used extensively, but you will rarely hear them called by that name. Instead, they are universally referred to as Residual Current Devices (RCDs) or RCBOs (Residual Current Breaker with Overcurrent protection).
The biggest practical difference between European and North American ground fault protection lies in where the devices are installed.
Europe: RCD protection is almost entirely centralized inside the main consumer unit (breaker box). A single high-capacity RCD typically shields multiple complete circuits (e.g., all the wall sockets in half the house).
Personal Life Safety: The European standard for general socket outlets and wet areas is a 30 mA trip threshold.
Because modern appliances use sophisticated power electronics, modern European regulations place strict emphasis on the Type of RCD installed

By: Tomi Engdahl

Tomi Engdahl — Sun, 20 Aug 2023 09:49:33 +0000

Water and electricity
https://youtu.be/1tfvtJyucHc

By: Tomi Engdahl

Tomi Engdahl — Fri, 30 Sep 2022 12:44:13 +0000

AFDDs & BS7671 Amendment 2 – What you need to know!
https://www.youtube.com/watch?v=d-Ew7RcA_Qw

The latest version of IET wiring regulations BS7671 Amendment 2 is now a requirement for new UK electrical installations. One of the major changes is the mandatory use of Arc Fault Detection Devices AFDDs in certain types of buildings and applications.

BS7671 AMD2 Effective date 28th September 2022

In partnership with Lewden Palazzoli, we’ve produced this training module to help update electricians, specifiers and electrical wholesalers.

For more FREE Training modules, checkout eFIXX Know How
https://www.efixx.co.uk/knowhow
====================================
00:00 AFDDs
00:39 Content elements
01:11 Circuit protection
01:50 Overload
02:07 Short circuit
02:35 Old fuses
03:03 Insulation
03:35 RCD
04:07 Arc faults
05:34 Series and parallel arcs
06:11 What is a parallel arc
06:57 Exception to the rule
07:54 Protection for the pugged in load(s)
08:25 AC waveform
08:37 Arc fault waveform
08:53 Inside an AFDD
09:40 Will sparks cause an AFDD to trip
10:44 Overvoltage protection
10:57 Do I still need a type 2 SPD
12:40 Self-test function
13:33 The LED on the AFDD
14:06 What the Regs say about AFDDs
16:00 What does recommend mean

Complete the AFDD CPD training module
http://hub.efixx.co.uk/lewden-afdd-cpd

By: Tomi Engdahl

Tomi Engdahl — Tue, 14 Sep 2021 17:14:36 +0000

https://www.electricaltechnology.org/2021/09/afci-arc-fault-circuit-interrupter.html

By: Tomi Engdahl

Tomi Engdahl — Wed, 10 Jun 2020 20:33:15 +0000

https://www.electricaltechnology.org/2020/06/difference-between-gfci-afci.html

By: Tomi Engdahl

Tomi Engdahl — Wed, 22 Jan 2020 11:02:15 +0000

Arc Fault Detection Device, Circuit Protection | Eaton
https://www.youtube.com/watch?v=UtOmau4ym1Q

Eaton AFDD+ – Incorporating the next generation of detection technology, the Eaton AFDD+ provides enhanced fire protection, what reduces the risk of electrically ignited fires, by detecting arc fault currents other protection devices can’t.

By: Tomi Engdahl

Tomi Engdahl — Tue, 21 Jan 2020 09:24:30 +0000

Arc Fault Detection Devices (AFDDs) #e5 Vienna Visit to Eaton’s Test Centre to Validate AFDD’s PT 1
https://www.youtube.com/watch?v=hdTRG1gm3W8

So the two Pauls took a trip to Vienna to the R&D labs of Eaton to gain assurance, learning, and confidence in what is new to the UK in AFDD devices.

By: Tomi Engdahl

Tomi Engdahl — Tue, 21 Jan 2020 09:22:29 +0000

The arc fault detection device (AFDD) S-ARC1
https://www.youtube.com/watch?v=E4aqXOJwQtc

The arc fault detection device (AFDD) S-ARC1 provides maximum safety in the electrical installation of all buildings, thus protecting people and valuable assets. By early detecting arc faults and disconnecting the affected circuit the AFDD offers reliable protection with easy installation, bridging the gap of series arc faults which cannot be detected by MCBs.
Combined with a Residual Current Circuit Breaker (RCCB) as upstream device, the S-ARC1 series provides the best solution for complete protection in the switchboard.

By: Tomi Engdahl

Tomi Engdahl — Tue, 21 Jan 2020 09:22:03 +0000

AFDD protection by Siemens

https://youtu.be/uAorINs1DAM

https://youtu.be/fnEgu4mlpGs