Hmmmm. Doesn't Table 3A (i.e. the relevant Standards) require that the RCD satisfied the maximum permitted trip times at all three currents (x1, x2 and x3)? If so, merely showing that it complies at 1x would not be sufficient.
Kind Regards, John
RCD tripping problem
- Thread starter Mike2007
- Start date
Kind Regards, John
Sponsored Links
Yes, and the 0° & 180° @ 1x & 5x tend to overlap.
The 200ms mentioned above applies to sites where the maximum mcb disconnection time is 0.2s - logically.
I can't remember, off hand, why the normal disconnection time is 300ms rather than 400ms, as in 0.4s for mcbs.
The 200ms mentioned above applies to sites where the maximum mcb disconnection time is 0.2s - logically.
I can't remember, off hand, why the normal disconnection time is 300ms rather than 400ms, as in 0.4s for mcbs.
Thanks all. . .
Here's our GFCI max trip times
http://www.interfire.org/features/gfi.asp
apparently based on the work of Charles Dalziel who did shock research in the 60s on people and large dogs.
The internal relay probably can't trip faster than 15 mS.
We might have 1 or 2 vac on the neutral depending on the current being drawn and conductor size, and if this wire were paralleled with the grounding conductor you'd need to do a parallel resistor calculation to see how the current would split up.
Of course, the resistance of a bad connection would be hard to know and possibly changing with time and current flow.
Here's our GFCI max trip times
http://www.interfire.org/features/gfi.asp
apparently based on the work of Charles Dalziel who did shock research in the 60s on people and large dogs.
The internal relay probably can't trip faster than 15 mS.
We might have 1 or 2 vac on the neutral depending on the current being drawn and conductor size, and if this wire were paralleled with the grounding conductor you'd need to do a parallel resistor calculation to see how the current would split up.
Of course, the resistance of a bad connection would be hard to know and possibly changing with time and current flow.
Sponsored Links
We're probably talking about different things. As I said, one has to assume that, if they include the maximum trip times for 2xrated, compliance BS EN 61008-1 and BS EN 61009-1 requires that RCDs satisfy that, as well as the criteria stated for 1x and 5x. However 'BS7671 testing' not requiring a 2x test is a rather different matter. In any event, as we've discussed, it's all a bit moot, since, in practice, RCDs usually seem to achieve better than the required 2x trip times with only 1x current - so scenarios such as Eric postualted probably arise rarely, if ever.
Perhaps not explicitly "2x", but many meters (like, AFAIAA, all the recent Flukes) offer a 'variable RCD current' facility, which enables one to manually set whatever current one wants.
Kind REgards, John
Are we confusing MCB and RCD ratings. ?
MCB operate on the load current with slow acting thermal and fast acting magnetic mechanisms each with its own time versus current graph.
RCDs operate on the difference between currents in the live and neutral passing through the sense coil. The load current is not part of the equation.
MCB operate on the load current with slow acting thermal and fast acting magnetic mechanisms each with its own time versus current graph.
RCDs operate on the difference between currents in the live and neutral passing through the sense coil. The load current is not part of the equation.
I don't think so - certainly not me. All those who have engaged in the subsequent discussion have assumed that Porque223's request/question related to the relationship between RCD trip times and the L-N imbalance current which caused it. I suppose it's possible that he meant something else, so I suppose it's just about possible that he was 'confused'.
Indeed, and I've seen no mention of load currents anywhere in the discussion, the 'rating x1, x2 and x5' currents we've been talking about (i.e. 30mA, 60mA and 150mA for a '30mA rated' RCD) are L-N imbalance (or 'test') currents.
Kind Regards, John
I'm not sure what you mean by 'explicitly'.
My and your 1652 cannot test at 60mA so a 2x test cannot be done.
I meant that there is no "2x" setting available on the meter.
If, like mine, yours is literally a '1652', then that's true. However, my understanding is that from 1652C onwards (I'm not sure about 1652B), you could set any test current you wanted, including 60mA.
Kind Regards, John
No, mines a 1652B and cannot do it.
There is nothing in the Fluke manual - which also covers 1653s about this.
The EIC (that I use) only require recording of 1x and 5x values.
I don't think I have ever read anywhere about anyone doing or even just discussing 2x tests.
There is nothing in the Fluke manual - which also covers 1653s about this.
The EIC (that I use) only require recording of 1x and 5x values.
I don't think I have ever read anywhere about anyone doing or even just discussing 2x tests.
I have looked up the 1654 and it would seem to be no different than our 1652s.
As I said, I never meant to suggest that 'BS7671 testing' required a 2x test - merely that such a test would, under some uncommon circumstances (such as Eric postulated) be necessary to confirm full compliance with the relevant Standards for RCDs.
Kind Regards, John
Ah. that 'VAR' only refers to the currents that the machine can do - 10, 30mA etc.
You cannot 'set' it to any current you wish, e.g. 60mA.
You cannot 'set' it to any current you wish, e.g. 60mA.
I didn't notice that bit.
It would seem that you are correct.
It would seem that you are correct.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
