 Welcome to the Network Engineering video blog. I am your host, Michael Crane. In this follow up to video number 83, Isolated Ground PDU Conversion, we investigate the capacitive coupling we measured between our Isolated Ground PDU's electronics and its enclosure. When we measured it with our Fluke Multimeter in video 83, it showed about 17 volts AC from the PDU case to equipment ground. But what's the current? Are we talking amps or microamps? And is it dangerous? Let's find out. Okay, so now what we want to do is we want to see how much power is actually getting transferred from the case into the equipment ground here, okay? To do that I'm going to use this little quarter watt 1K ohm resistor as a shunt resistor. So we can determine how much current is actually getting transferred from the case to the ground. So I'm going to go ahead and get this set up real quick and I'll be back. Okay, so here's the test set up. I've got one wire attached to the equipment ground, I'm sorry, to the enclosure mounting tab right here, all right? And it's going into one side of this 1K resistor and the other side of the resistor is going to the building ground which is simulating our equipment ground, all right? Then I just have the voltmeter measuring the voltage across the 1K ohm resistor, all right? So I'm going to turn the voltmeter back on, AC, and let's power this guy up. Looks like we've got about three millivolts, all right? Okay, well that 1K resistor wasn't working. It was showing about three millivolts. You notice when I first turned it on it kind of shot up and went down and jumped around and I believe we're in the noise, all right? So what I did is I went ahead and put a 10K shunt resistor in here and it's still powered off as you noticed. And if you notice, see all I have to do is just touch it. So we're down in the noise at this right here. We needed a bigger shunt resistor so I'm going to go ahead and turn this back on now. Okay, so now we're above the noise. Okay, so we're reading about 37, if it settles down, let's just call it 37 millivolts, okay? And some quick math tells us that, so 37 millivolts divided by 10K gives us about 3.7 microamps, all right? Okay, and that's pretty small, right? And if you're wondering why I'm using the shunt resistor instead of the fluke multimeter to measure the current, it was because just in case something bad happens, I didn't want it to, I'd rather have blow up the resistor than blow up my fluke multimeter. We can actually do this real quick and go ahead and power this guy off, all right? Plug him, put it down here in the microamp range. Let's see if we want microamps, all right? Turn this baby on, and it's saying about 2.9 microamps, let's see, yeah, yeah, getting down this low is really hard to measure because the multimeter's got shunt resistor in there, it's got a compensate for, and if you go on the EEV blog, Dave Jones has made a device called a microcurrent that is supposed to help fix this, so, yeah, it's called burden voltage, that's the term I was looking for, but anyway, we know it's about 3 to 3.7 microamps, right? Which is extremely small, so we don't have to worry about wasting too much power or muddying up the equipment ground with this, all right? Don't forget you can support the Network Engineering video blog by donation using a credit card and PayPal or by purchasing products at the MUXHALL store. Details and links are in the description under this video. Well, that's it for this video, if you liked the video give it a big thumbs up, that helps and hit the subscribe button, that really helps, if you have any questions or comments post them in the comments under this video. Thanks for watching and I'll see you next time.