Type A rcd . EICR coding ? etc

Very well, Gentlemen, the boiler manufacturer cannot be bothered to correctly fuse his appliance, expects there to be faults in his electronics, safety coverings, etc. and so we must fit a type A RCD. He cannot be bothered to put an Earth terminal on the casing and expects the piping not to be bonded to Earth and the CPC open circuit. That is the biggest load of A.. covering I have ever heard. This product does not pass the LV Directive, is unsafe, has no internal protection, and is expected to fail dangerously.


I think it would be reasonable for someone to describe what fault exactly could require a type A RCD. As you all know by now I don't believe there is a credible scenario without multiple faults which could make a type AC fail to disconnect this appliance. What is the scenario where normal thermostats (230V) could cause a DC fault? If they are special LV types they are inherently not dangerous. How could this appliance require personnel protection? Therefore WHY is an RCD required? If the reason is because of incorrect installation then that is "Someone Else's Problem", not the Boiler manufacturer or BS7671. Andy may care to check out a few boilers, the thermostats tend to drive timers/controllers that have relays, and the thermostats are 230V, they depend on that for the heater to reduce hysteresis. Just in case anyone is wondering, failure of one diode in a bridge rectifier feeding large smoothing capacitors, does nothing much if open circuit, and takes a large current if short circuit. The appliance fuse (perhaps 3A but should be 1A) pops immediately. Power isolated, no problem. No reasonable fault can cause any DC on the mains, so an RCD requirement is odd unless it is as my paragraph 1.


I have done a lot of experiments with several makes of type AC RCDs and have yet to find one where small levels of DC (real DC not rectified waveforms) prevent operation. Some of them have somewhat reduced sensitivity at modest levels of DC (30-50 mA) which is not a problem except for personnel protection. They all work with rectified waveforms. The tests are not exhaustive but a guide. JW is not the only one who tests things!


Note to Chris, your inverter either has a large inrush or excessive current through EMC filters. My Japanese 4kW one is fine on an RCD < 10mA and no significant inrush. It is a PFC corrected type, so no rectifier/capacitors off the mains.


I am interested in answers to my questions above, they are not "getting at" any of the posts above, all of which are useful.

Very well, Gentlemen, the boiler manufacturer cannot be bothered to correctly fuse his appliance, expects there to be faults in his electronics, safety coverings, etc. and so we must fit a type A RCD. He cannot be bothered to put an Earth terminal on the casing and expects the piping not to be bonded to Earth and the CPC open circuit. That is the biggest load of A.. covering I have ever heard. This product does not pass the LV Directive, is unsafe, has no internal protection, and is expected to fail dangerously.


I think it would be reasonable for someone to describe what fault exactly could require a type A RCD. As you all know by now I don't believe there is a credible scenario without multiple faults which could make a type AC fail to disconnect this appliance. What is the scenario where normal thermostats (230V) could cause a DC fault? If they are special LV types they are inherently not dangerous. How could this appliance require personnel protection? Therefore WHY is an RCD required? If the reason is because of incorrect installation then that is "Someone Else's Problem", not the Boiler manufacturer or BS7671. Andy may care to check out a few boilers, the thermostats tend to drive timers/controllers that have relays, and the thermostats are 230V, they depend on that for the heater to reduce hysteresis. Just in case anyone is wondering, failure of one diode in a bridge rectifier feeding large smoothing capacitors, does nothing much if open circuit, and takes a large current if short circuit. The appliance fuse (perhaps 3A but should be 1A) pops immediately. Power isolated, no problem. No reasonable fault can cause any DC on the mains, so an RCD requirement is odd unless it is as my paragraph 1.


I have done a lot of experiments with several makes of type AC RCDs and have yet to find one where small levels of DC (real DC not rectified waveforms) prevent operation. Some of them have somewhat reduced sensitivity at modest levels of DC (30-50 mA) which is not a problem except for personnel protection. They all work with rectified waveforms. The tests are not exhaustive but a guide. JW is not the only one who tests things!


Note to Chris, your inverter either has a large inrush or excessive current through EMC filters. My Japanese 4kW one is fine on an RCD < 10mA and no significant inrush. It is a PFC corrected type, so no rectifier/capacitors off the mains.


I am interested in answers to my questions above, they are not "getting at" any of the posts above, all of which are useful.