Husnen:
Let’s just say, in this scenario, when this circuit is on, I’m going to set up my voltmeter to the min-max range. I’m going to conduct the IR test as if I am just charging the circuit. Really, we know that we’re charging this ICBO, so let’s just charge that. As soon as the charging is done, I’m going to replace it with my multimeter and see how much maximum voltage it holds. Doing that, I can see that it’s about 15.8 volts. Now, that’s not a lot, and it is probably discharging either through the internal bleed resistor or the resistor of the voltmeter, but the peak voltage I measured here was 15.8.

Now, let’s try and turn on one more circuit. There’s only two circuits, on one faulty circuit and one circuit that is not faulty. Now, since that circuit doesn’t have any fault, you would think that it would repeat that same situation, so let’s try that. Let’s disconnect that, charge up our circuit, and we’ll replace it without. We’ll set up our multimeter to peak hold again, and here we go. Last time, we had about 15 volts, and now we have about 74.9 or 75 volts. Just by adding another circuit, which is not even faulty, what I’ve done is I’ve increased the voltage that is stored in these RCDs or RCBOs, which goes to show that what’s happening is both of these are now connected together, and they’re both holding the charge.

If I look at that scenario, if I trace how the voltage or the current is flowing through the circuit… Let’s have a look. When I put this IR tester on this earth bar, the current is going from this wire going to this circuit on the active. It’s going from here to where all the actives are connected on the input, and then all the RCDs are now also getting the current. However, because all the other ones are off, only these two are on, the current is going through this RCBO and then coming out going to the neutral bar and completing the circuit. We are really charging both of these RCDs. With that in mind, if we turn on the third RCBO, it’s possible that we might hold more charge or more voltage than this one, so let’s try out that scenario.

I will turn off the peak hold, turn on my IR tester, turn on one more circuit, and charge the RCBOs. Set up my multimeter to peak again, and this time, we’re getting 105 volts. We can say that now all three of these RCBOs were charged, so if I repeat that test with all the circuits on and see how much voltage that holds, it might tell us what exactly or how much charge will be there in this circuit when we have this fault. Now we have all the circuits on, we’re going to do an IR test on earth bar and neutral where we have fault only on this circuit, and we’re going to set up our multimeter to peak hold.

As soon as we remove the IR tester, I’m going to put in the multimeter. I’m seeing about 188 volts being stored just on the RCBOs here. Now, if there was a ballast or a fluoro or some sort of circuit connected to this installation, even if there was no fault in it, we can see that, with this scenario, there is a chance that we’ll charge up that ballast or capacitor in that installation, which means the charge hold might be longer or more, depending on what’s connected there. This is no different to connecting our IR tester across active and neutral. To do that, we will do a quick repeat of that same test on active and neutral off in RCBO that doesn’t have any fault.

In this scenario, I have turned off the circuit that has no problem. That way, that circuit isn’t in question, but I will conduct an IR test across an active and neutral off only one circuit and see whether that still charges or not. Let’s try that out. As my IR tester is on, I’m going to do a test on this RCBO, and we’ll do it in the same way where we will replace our RCD, so let’s chart that up. I’m charging that RCBO. I will set my multimeter or voltmeter to peak hold, and you can see that’s still holding about 167 volts, which means that what we were doing in this circuit where there was an active to earth fault was really just charging the RCBO, which was holding the charge. Now, it doesn’t hold for too long, but we don’t really know how long it will hold, because it’ll depend on the manufacturer. Every manufacturer might be using a different type of capacitor, so we’re not sure about that.

Plus, also, we don’t know what other loads are connected in the circuit, so in our fault board, there is a fluoro connected in the circuit, and that ballast might hold charge for a little bit longer than RCBOs. It’s a good idea to know that there is a possibility of an IR to charge an installation, whether it’s dead or not. Thanks for watching.