MCB/RCD on consumer unit tripping

[roys]

AFDD’s, are they an up front device that will trip everything, just like RCDs did when they were fitted up front?

Genuinely interested, never fitted one before.

 

[Sharpend]

AFDD’s, are they an up front device that will trip everything, just like RCDs did when they were fitted up front?

Genuinely interested, never fitted one before.

I believe they are although I think I remember reading somewhere that the mfrs were producing a combined AFDD with MCB/RCBO  ??

 

[Murdoch]

Here's an example 

https://uk.rs-online.com/web/p/rcbos/2027050/

 

[Sharpend]

Link goes to unknown? 

 

[roys]

If they are an upfront device, which going by the Google search I just did AFDDs appear to be, how do they comply with the division of circuits reg 314......?

 

[Murdoch]

Link goes to unknown? 

strange as it worked for me. 
 

try searching for AFDD on the RS site

 

[Sidewinder]

I believe they are although I think I remember reading somewhere that the mfrs were producing a combined AFDD with MCB/RCBO  ??

They have, Wylex/Crabtree.

Eaton have one but it is double module.

They are not like an RCD, they are a per circuit device.

 

[binky]

They are not like an RCD, they are a per circuit device.

Hence the horrendous cost! 

 

[Murdoch]

They have, Wylex/Crabtree.

Eaton have one but it is double module.

They are not like an RCD, they are a per circuit device.

interesting isn’t it that 2.5 years after the 18th edition was published there is a serious lack of knowledge about these devices and the powers that be think they can mandate them?

I have been making my way through the E5 podcasts and it’s fair to say that they ,with their combined knowledge seem to struggle with them AND they acknowledge the lack of communication from the powers that be and the manufacturers

its hard enough earning a living right now without having to try to justify decisions made by these organisation when they spend little or nothing educating the public

It will take a lot for me to shift my position on these expensive white elephants 

 

[Sidewinder]

How far through our podcasts have you got, two of us went to Eaton in Vienna to the R&D labs, we know they work, and they work well.

The issue is that the standard for them is a limitation for their use.

i.e. it only requires detection of a 2.5A or more arc.

Unfortunately, due to work commitments and my deteriorating health, I think I only did one or two of them.

 

[Murdoch]

How far through our podcasts have you got,

The next one is 83 but I haven’t listened to them all

anything over 45 minutes is past my tolerance and some aren’t relevant so I will stop listening and delete it 

I found the series on SPD particularly tedious .... 

people blowing their own trumpets need editing out

 

[Andy™]

i.e. it only requires detection of a 2.5A or more arc.

sp in a house with all LED lighting (and even non LED lighting), the max current for the entire circuit with everything on at the same time is far less than 2.5a, then having an AFDD would be of no use

 

[binky]

sp in a house with all LED lighting (and even non LED lighting), the max current for the entire circuit with everything on at the same time is far less than 2.5a, then having an AFDD would be of no use

when a broken conductor or loose connection is arcing it probably draws more than 2.5A 

 

[Geoff1946]

when a broken conductor or loose connection is arcing it probably draws more than 2.5A 

Surely if it's a series fault the current will be limited by the normal circuit load ?

 

[binky]

Surely if it's a series fault the current will be limited by the normal circuit load ?

6A max I presume? 

 

[Geoff1946]

6A max I presume? 

Yes if the circuit is loaded to maximum but that will be rare on modern (led) lighting. If I put on every light in my house, simultaneously, I don't think I would reach 500 watts, so < 3amp..

 

[Sidewinder]

The next one is 83 but I haven’t listened to them all

anything over 45 minutes is past my tolerance and some aren’t relevant so I will stop listening and delete it 

I found the series on SPD particularly tedious .... 

people blowing their own trumpets need editing out

You probably ignored and deleted my first one then.

 

[Sidewinder]

sp in a house with all LED lighting (and even non LED lighting), the max current for the entire circuit with everything on at the same time is far less than 2.5a, then having an AFDD would be of no use

The argument there is that an arc at 230V & 2.5A does not have enough energy for ignition of the insulation, hence no requirement for detection.

The only place that falls down is a parallel arc at the start of a short circuit in the wiring, but, the argument there is that it will quickly cascade into a short circuit and the MCB will then trip.

 

[Sidewinder]

6A max I presume? 

No the current will be the actual real time loading on the circuit, so if it's just a few LED's with only one on, it will be just the load of say the one 5W LED.

So perhaps in the mA range.

Also see my other post for the theory behind this.

I have a good idea how they function etc. because I was invited to Eaton in Vienna to look at their ideas behind the development.

Yes if the circuit is loaded to maximum but that will be rare on modern (led) lighting. If I put on every light in my house, simultaneously, I don't think I would reach 500 watts, so < 3amp..

Exactly.

 

[binky]

No the current will be the actual real time loading on the circuit, so if it's just a few LED's with only one on, it will be just the load of say the one 5W LED.

So perhaps in the mA range.

Also see my other post for the theory behind this.

I have a good idea how they function etc. because I was invited to Eaton in Vienna to look at their ideas behind the development.

Exactly.

so not likely to be any use on lighting circuits then?