I have had several occasions when replacing an existing Type AC RCD with a Type A solved the tripping problems after the customers bought a Bosch direct drive washing machine or a new hob.

The one Bosch washing machine appeared to be blinding the 30 mA RCD and was tripping the upfront Time-delayed 100 mA RCD, you could not even run the washing machine, but the RCDs tested out fine.

Some of these jobs have left me feeling like tearing my hair out, having been through testing and upgrading but still having tripping issues. Earlier this year I had one such problem and replaced the consumer unit that had an upfront Type AC RCD main switch with a new CU that has all Double Pole Type A 30 mA RCBOs, the customer is convinced there’s a problem with the central heating that is not on the same circuit, I think it’s an appliance or that they have many surge protected extension leads around their home that they are using on the circuit that trips, any current that passes through the surge protection built into the extension leads will potentially trip the RCD.  We are in another “wait and see” stage of the elimination process.

Potentially there’s just too many electronic devices in peoples homes these days to be able to quickly and easily identify issues, it ain’t like the old days when the issues were as simple as a dodgy immersion heater controlled by a mechanical clock.

I have had several occasions when replacing an existing Type AC RCD with a Type A solved the tripping problems after the customers bought a Bosch direct drive washing machine or a new hob.

The one Bosch washing machine appeared to be blinding the 30 mA RCD and was tripping the upfront Time-delayed 100 mA RCD, you could not even run the washing machine, but the RCDs tested out fine.

Some of these jobs have left me feeling like tearing my hair out, having been through testing and upgrading but still having tripping issues. Earlier this year I had one such problem and replaced the consumer unit that had an upfront Type AC RCD main switch with a new CU that has all Double Pole Type A 30 mA RCBOs, the customer is convinced there’s a problem with the central heating that is not on the same circuit, I think it’s an appliance or that they have many surge protected extension leads around their home that they are using on the circuit that trips, any current that passes through the surge protection built into the extension leads will potentially trip the RCD.  We are in another “wait and see” stage of the elimination process.

Potentially there’s just too many electronic devices in peoples homes these days to be able to quickly and easily identify issues, it ain’t like the old days when the issues were as simple as a dodgy immersion heater controlled by a mechanical clock.

Amen to that brother.

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.

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?

Sparkingchip said:

Potentially there’s just too many electronic devices in peoples homes these days to be able to quickly and easily identify issues, it ain’t like the old days when the issues were as simple as a dodgy immersion heater controlled by a mechanical clock.

Indeed. So it would be good design perhaps to provide more socket outlet circuits with less socket outlets on them rather than sprawling rings. Then again that might be thwarted by the “recommendation” to fit costly AFDDs to socket circuits.