whjohnson said:

I'm still not 100% convinced about type A's being needed. Think of the risk this way, there must still be 1000's of existing installations wholly dependent upon the old BS3036 protection. Does this mean they are unsafe?

'Safety' is all relative.

Based on that argument then we could still carry out out work older edition of BS7671 (16th, 15th or 14th Editions???)

Any new work will need to meet the current wiring regulations, we don't have a problem on adding RCDs if we have sockets or buried cable to install - it just gets done.

Rewirable fuse? No MCB, No RCD, No AFDD, No SPD?

MCB? No RCD, No AFDD, No SPD?

MCB & Type A/C RCD? No AFDD, No SPD?

MCB & Type A RCD? No AFDD, No SPD?

RCBO Type A/C, No AFDD, NO SPD?

RCBO Type A, No AFDD, No SPD?

Another way to look at it do the incremental requirements in each new addition of BS7671 improve safety. All of the items listed above do add a level of safety that is worth considering. 

The difficulty I have is understanding how much or little DC current will cause a type-AC RCD to be blinded. Also how much can we expect from the DC components in a typical home. Is it only an issue for the EV and Solar PV installations?

I agree with the puzzle over Type A/C vs Type A, I don't reckon enough results are in just yet. I can understand the physics behind the 'blinding' phenomena, but just how prevalent is it out in the wild?

One question - does the incremental requirement for a AFDD make an installation safer when it won't pick up a series arc on a ring final? Or even a arc due to faulty flex to an appliance downstream of the secondary of a transformer?

I think we can quickly reach a point whereby we fulfill the law of diminishing returns here, with manufacturers running around scratching their arses looking for the Next Big Thing to sell us, and I reckon Peak Snake Oil has been reached with AFDDs.

What next? A Requirement for the electrical installations in all domestic dwellings to be constructed in galvanized steel conduit installed in fireproof concrete ducts? All accessories to comply with Intrinsic safety standards? All wiring to be done in MICC? Where should it stop?

I agree with the puzzle over Type A/C vs Type A, I don't reckon enough results are in just yet. I can understand the physics behind the 'blinding' phenomena, but just how prevalent is it out in the wild?

One question - does the incremental requirement for a AFDD make an installation safer when it won't pick up a series arc on a ring final? Or even a arc due to faulty flex to an appliance downstream of the secondary of a transformer?

I think we can quickly reach a point whereby we fulfill the law of diminishing returns here, with manufacturers running around scratching their arses looking for the Next Big Thing to sell us, and I reckon Peak Snake Oil has been reached with AFDDs.

What next? A Requirement for the electrical installations in all domestic dwellings to be constructed in galvanized steel conduit installed in fireproof concrete ducts? All accessories to comply with Intrinsic safety standards? All wiring to be done in MICC? Where should it stop?