AC Type RCD No PV or Car Charger C3 or C2

Lookin at NAPIT code breakers under section 4.18 they say  (Code C2)

RCD fitted is type AC and has pulsating  DC currents present from connected equipment such as EV, PV, switched mode power supplies, domestic appliances with VSD's etc,  which may/will mask fault current and prevent the type AC RCD from operating.

As it's more or less impossible to recreate worst case scenario for DC leakage while carrying out a RCD test during an EICR, if following this for nearly all domestic environments the code would have to be C2. Nearly all homes will contain many devices with SMPS as they are in everything from TV's, radios, computers, phone chargers etc.

I do wonder how many manufacturers just relabeled their type AC rcd's as type A because they were compliant, but won't inform the outside world because they want to sell new equipment.

Alan B said:

Lookin at NAPIT code breakers under section 4.18 they say  (Code C2)

That has to be wrong. That would render a vast number of simple installations obsolete.

lyledunn said:

My take is that something that "may give rise to danger" is something that could be potentially dangerous, which a code 3 is definitely not.

Agreed. lyledunn makes a good point.

On the next page(522) we have, "GUIDANCE FOR RECIPIENTS". C2 (as well as C1) means, "the safety of those using the installation is at risk" (emphasis in the original) and accordingly that remedial work should be undertaken "as a matter of urgency".

Alan B said:

Lookin at NAPIT code breakers under section 4.18 they say  (Code C2)

That has to be wrong. That would render a vast number of simple installations obsolete.

lyledunn said:

My take is that something that "may give rise to danger" is something that could be potentially dangerous, which a code 3 is definitely not.

Agreed. lyledunn makes a good point.

On the next page(522) we have, "GUIDANCE FOR RECIPIENTS". C2 (as well as C1) means, "the safety of those using the installation is at risk" (emphasis in the original) and accordingly that remedial work should be undertaken "as a matter of urgency".

That has to be wrong.

I think it's certainly more nuanced - surely it'll take a significant amount of d.c. residual current to blind even the simplest of AC type RCD - I would have thought d.c. a mA or two would at worst de-sensitize it a bit (e.g. maybe tripping at 29mA instead of 27mA - but still within spec) - with increasing d.c. residual currents of course there comes a point where it becomes a problem. The question is how likely is it that a typical domestic will produce enough d.c. residual current to be a problem? Even A types aren't a complete panacea to this issue - they're only good up to 6mA d.c. - after that their performance is as undefined as AC types.

  -  Andy.

Considering the time it take to write/publish a BS like BS7671 the lifecycle should start to consider the recommendation of of type B as a minimum for BS7671 Ammendment 5 or 19th edition. Ideal for EV chargers, solar PV (inverters).  

Lets not forget the type F as well for inverter driven loads like washing machines and heat pumps. 

 I am sure that will be an interesting debate for the JPEL Team.