I wanted to know if anyone has used this type of device to test their electrical installation.
https://www.distrimesure.com/fr/217-testeurs-et-controleurs-de-disjoncteurs-differentiels
Indeed, I accidentally failed a plug without ground, and I wonder if my differential breaker still works well.
It is necessary to know that in France the counters are changed and I wonder if phase and neutral would not have been reversed.
Some says it's the same with connexions inverted?
I say this because I made a mistake by 2 times connecting my multimeter which was actually in ohmmeter position between ground and phase. A beautiful spark, but no disjunction.
I wonder if we can cause the disjunction by connecting a resistance between phase and ground. But what is the rule of calculation for this one for 30ma for example. I think that these small devices do only that in circuit breaker test. (?)
Good after for 30 euros, it can always be used.
Your opinions.
cdt
I also can't quite figure out everything you're saying in the original post.
But basically, to test an RCD, yes, you just use a resistor between line and ground. In fact, that is precisely what the test button on the RCD itself does! So you really don't need an external tester to do basic testing of the RCD. Just press the test button and see if it breaks the circuit.
The formula is just Ohm's law: I = V/R. Or more usefully here, R = V/I.
230V/30mA = 7. 667 kΩ
So you'd choose the next-lowest standard resistor value, so 7.5 kΩ.
As a proof, 230V/7.5 kΩ = 30.67 mA
Perfect!
If you wanted to characterize the RCD a bit better, you might use a few values to make sure it's sensitive enough but not more sensitive than it is supposed to be.
What the better testers do that you cannot do easily is testing how fast it reacts.
A very simple tester like that VT35 doesn't tell you much more than the built-in test button.
They function by comparing the current flow between the phase line and Neutral. Whenever there is deviation in current flow which passes the RCD's rating (i.e. 30mA), then the device will trip and make an open circuit.
Just to be clearer, it's not a "deviation" in total current passing through the RCD (the total current can rise and fall how it wants) that trips it, it's the size of any
imbalance in current between the line and neutral.