What is a Floating Neutral Generator?

hey my name is ben thanks for stopping by today we're going to be talking about floating neutrals versus bonded neutrals when it comes to generator applications like this generator that i have right behind me here so i'm just going to show you how this particular generator is set up at first and then we're going to go through several different aspects of kind of understanding and fleshing out that concept of whether or not the neutral should be bonded inside of your generator or not so the generator we're looking at today is just this little portable propane and gasoline generator that i've had for quite a while and used it a couple of times and in order to figure out whether or not you have a bonded neutral one of the best places to look is just in the documentation that came with the generator it should say somewhere whether or not the generator is bonded so what we're going to actually do is i'm going to show you guys the electrical wiring diagram and we should be able to take a look at that and see whether or not the neutral is bonded oftentimes if you have a floating neutral generator though it'll say somewhere right on it that the generator is a floating neutral generator so right here we have the wiring diagram for this particular generator or it's the one that was located in the user manual for this one anyway and if we look at the way this is all laid out here you'll see right here here's our main winding which is supplying our 240 volts and it's 120 volts from each half of the coil so the center tap of that winding is where our neutral is derived from where the neutral comes from so you can see right here we have this wire that comes up and it says w right there and that's for a white wire and then it right here connects on and continues and ultimately connects to the neutral prong on the different uh receptacles and then it also branches off right here where this yellow highlighted point is and this comes down and is bonded to the ground if we follow this green highlighted wire you'll see that this connects to the grounding prong of both of both the 240 volt receptacle and the 120 volt ones and it ultimately comes over here to where we have a grounding point on the actual frame of the generator that we can connect this to a grounding rod so right here between here and here this is our basically jumper that's bonding our w or our center tap of that transformer to ground and it's referencing it to ground so what i want to do now is i'm going to show you where this jumper is located inside of my generator so on the end of your generator typically you'll have a cover like this that you'll just have to remove in order to inspect whether or not your neutral is bonded there are there is another way to tell whether or not your neutral is bonded and i'll show that to you here in just a couple minutes but we're just going to start by looking at the actual wires and if you wanted to make your generator a floating neutral generator which is something we'll also talk about a little bit later this is how you would do it and actually champion and i don't know if there are other generator manufacturers but there are a few generator manufacturers that actually allow you to and show you how to separate the neutral from the ground in order to make your generator be a floating neutral generator okay so here is what we are looking at in that wiring diagram you can see we have this white wire right here and it comes from down in here this is uh where that white wire lands coming from that center tap of the windings and it lands right there and from right here to right here is where we would typically see our jumper now i actually already knew this but basically this generator actually does have a floating neutral which is very surprising because it doesn't say it anywhere basically what we have is some bad documentation and i think that's just part of when you purchase chinese generators they don't have great documentation so let me just prove to you that this is not bonded right now and we're just going to go from this terminal right here which is our neutral to ground and you'll see that we have no continuity it's reading like it's a capacitor but there is no continuity there if we just switch it into ohms it says open lead and if i just go across all of these just to make sure every single one of them is an open lead so that means that this particular generator is not bonded it is a floating neutral generator now i am pretty displeased with the documentation from duromax on this particular one i actually thought this was a bonded neutral generator and there are some safety concerns or things to be aware of when you're working with a bonded neutral generator versus a floating neutral generator so that's what we're going to kind of go through next i'm going to show you one more way as to just how you can tell between a bonded neutral generator and a floating neutral generator without having to take that end cover off to look inside of there so here we have our electrical tester and we're just going to go ahead and verify whether or not this is a bonded neutral or floating neutral just using these receptacles here and the way we can do that is just to take one of our prongs and put it in the neutral side of one of the receptacles like that so now we're basically connected to the neutral and then go ahead and test to the ground grounding point of the generator and you can see right there it's telling us open lead except for the grounding prong if we check from the grounding prong you'll see that we do have continuity so if this were a bonded neutral generator we would have gotten continuity from the neutral to the ground because they're basically connected together which i'm going to show you a little bit later here with them bonded so that you can see that in a little bit more detail all right so we have a floating neutral generator we eventually established even though the instructions were not clear and the wiring diagram showed that this was a bonded neutral generator it's actually a floating neutral generator and actually i found on their website in the q a section they do actually answer somebody's question say oh yeah it's a floating neutral generator but nowhere in the instructions does it say that so buy a nicer generator get a honda or something else that's not a cheap chinese one like what i have here so now that we know we have a floating neutral generator we're going to simulate a couple different things starting by simulating a short circuit so here i have a just appliance cord that i salvaged and i'm going to create a dead short between the hot leg of one of these 120 volt plugs to the frame of the generator so it's as if we had a bare wire that somehow came up against the frame of the generator and i'll show you what happens obviously optimally we'd want the generator to trip the breaker when that happens but i don't think that it's going to do that because basically the frame is its own thing it's separate from everything else now the generator is still not grounded separately it doesn't have a ground rod attached to it but we're going to simulate that next so we'll start with this we've got our breaker turned off right there and we're going to just attach our appliance cord right there and then we're going to connect our hot wire to the frame of the generator so we're just going to do that here we can actually do it right here on this ground um but i don't think i'm going to do that i think i'm just going to pinch it in this this handle here all right like oh it cut it right off just like that all right that's pinched in there now so as soon as we apply power to this it's going to have a dead short of 120 volts directly to the frame of the unit so i'm going to be really cautious while we do this test so what we're going to do is we're going to start the generator and i'm going to flip the breaker on so that we have power coming through this cord here which is then shorted out to the frame of the generator and then we're going to check for voltage from the frame of the generator to ground as well as the neutral prong this left prong of this 120 volt plug to the frame just to see how much voltage we have on the frame of the generator and also just to see if that breaker will trip so here we go is so there you saw how we had 120 volts from the neutral prong to the frame of the generator but from the frame of the generator to ground we actually had zero volts which is really interesting and basically what that means is this is kind of like a separately derived system we have power coming from this generator but there isn't anything attached to the ground nothing other than like the feet of the generator that are sitting in the grass that that's the only thing that's really connecting the system to anything so when we connected 120 volts to the frame of the generator that little bit of connection that it had with the grass and the dirt basically was referencing that portion of the windings of the generator to ground so we had our 120 volts that we would typically measure from the dirt to 120 volt prong it was zero because that 120 volts was referenced to ground so it's kind of confusing but this is kind of a good example of that so the reason this creates such a hazardous situation is that if you were to have a metal framed appliance like this fan right here where the frame of the appliance is bonded to the ground prong so we have our ground prong right here on our appliance if we were to go ahead and just check for continuity from the ground prong to the frame of the unit we do have continuity there so you can see how this creates a hazardous situation where we have 120 volts on the frame of the generator which if we were to plug in this fan then would transfer that 120 volts onto the frame of the fan or vice versa if there were to be a short in the fan over here it would send power back through the grounding prong and to the frame of the generator so how do you fix this what is the solution to having a generator with a floating neutral we just saw what happens when you short 120 volts to the frame basically energizes the frame and energizes any grounded appliances that you may attach to it or vice versa so how would we make this safe you would kind of think intuitively that you would just attach a ground rod which we have an eight foot ground rod driven right there and we have attach it to the ground terminal on the generator i have my appliance cord plugged in there 120 volts will be on this black wire and i'm just going to short the black wire out to the frame of the generator and the frame of the generator is connected to that ground terminal right there so 120 volts straight to ground basically is what we're going to be doing and it should trip that breaker or that's what we want it to do my prediction is that it will not trip the breaker but i'll just show you so here we go we'll go ahead and start it up our breakers turn off right now we're gonna go ahead and turn on our breaker so we have a power now here so we're gonna go ahead and touch the end of this wire which has 120 volts on it to the frame of the generator you see that nothing happened let's try it down here nothing [Applause] so as you just saw having it grounded made absolutely no difference in clearing the fault we had a direct fault 120 volts to the frame of this generator and it did not trip so that's why everything comes back to being bonded that's why bonding is so important you have to have the neutral of your system bonded to the ground of your system somewhere so that you have a a fault current path because the electrons want to return to the source ground really has nothing to do with it other than the fact that ground happens to be a conductor so when we shorted out 120 volts to ground it was sending 120 volts to that ground rod right there and it didn't really care because there was no way for the electrons to go into the ground and come back to this generator because there was no connection there was no other connection it was basically just sticking one wire into the dirt does absolutely nothing unless that system is already connected to the dirt oh man this feels confusing doesn't it feel a little bit confusing it does feel a little bit confusing with an ungrounded system when the first phase or the first hot conductor comes in contact with any object whether it be the ground or the metal frame of a building nothing will happen because there's no way for the electrons to go out into the ground and back or into a metal structure and back a fault doesn't really occur until the second live conductor comes in contact with the ground this is hard to explain actually so there's an easy way to simulate having the neutral and ground bonded together you see this cord that we have plugged in right here you can see we have both the neutral and the ground wire there if we just twist those guys together we have created a bonded neutral generator just like that now i'm not saying that that's the correct way to do it or that you should use that as a solution but that's basically the exact same thing right here connecting that neutral and ground together is the same as if you had connected it in that side cover so we'll take our multimeter put into continuity mode and we'll just check from the neutral prong which is right here to the frame of the generator and you can see right there we have continuity so our generator now has a bonded neutral so i'm going to simulate what happens with a bonded neutral generator it's grounded and everything now if we go ahead and short that 120 volts out the same way that we did earlier what's going to happen is it's going to be a direct fault and it should trip that breaker almost immediately i don't really want to do this but i'm going to do this for you guys so that you know that i'm telling the truth here we go [Applause] so that is the gist of it you can see how having the frame of the generator bonded to the neutral and having the ground bonded to the neutral allows you to have a return fault current path so that when something shorts out it will disconnect because that's the primary goal of over over current protection is shutting the power off as quickly as possible once a fault has occurred so if you had a floating neutral generator and you're using it exclusively with extension cords you could have a direct short the hot to the ground and it would not trip the over current protection so you can see why that is not a good thing at all obviously if you have a short from the hot to the neutral then it will trip but essentially in the generator you want to have your neutral and your ground tied together if you're going to be using your generator exclusively with extension cords next we're going to talk about why you want a floating neutral generator after all that talk of why you don't want one i'll show you why we do okay for those of you guys who are new to this channel if you do me a huge favor hit that subscribe button and click the bell to be notified about future videos 90 or more of the views that i get on my channel are from people who never subscribe and i totally understand a lot of times you just want to watch one video and get on with your life but if you find value in this content and you would like to see a little bit more in the future do me a favor and hit that subscribe button we are approaching 100 000 subscribers which is awesome and so i'd appreciate it if you help us hit that goal hopefully we'll hit 100 000 in about two months but let's make it be one month yeah so what is a floating neutral generator good for good question and that is for connecting to a standby system or basically connecting it to a power inlet plug connected to an interlocked breaker i'll put a link to that video at the end of this video for you guys if you want to see how you get a generator interlock kit all set up but basically as you guys saw in my video about separating the neutral and ground in subpanels the whole idea comes down to you only want to connect or bond the neutral and the ground at one location so that is usually the first disconnecting means after your meter so you can see right behind me here there's the meter and then right next to it is the first disconnecting means so inside of that panel is where the neutral and ground are bonded together and consequently when you hook up a generator to a power inlet box it has four terminals as you can see right here and those terminals are two hot wires a neutral and a ground and since the neutral and ground are tied together in that first disconnecting panel it when you attach this cord to your generator it essentially bonds the neutral in the ground but not in the generator it does it inside of this panel let me just show you really quick where that is inside of the panel so you can kind of get a clear picture of this and we'll follow this all the way back to the generator so here we are inside of my first disconnect means after our meter so our meter comes over and feeds power into this first 200 amp panel has feed through lugs down here which feed down and over across into the house over there but you can see that on the neutral bus we have both ground and neutral wires landing there and you can see right there at the top there is our green bonding screw that is still installed and that's basically bonding the frame of this panel to that neutral bus so all of our neutrals and grounds are connected to the same place we have a ground rod which you can see that copper wire right down there goes down and attaches to a ground rod down here and then if we look at the wires that are coming from our power inlet box which is right back here right back here is our power inlet box for the generator those wires come up and attach to this interlock breaker right there so we have our two hot legs and then our ground and neutral wires attach right there right next to each other so you can see they're going to the exact same place so i'll go ahead and get our cord connected but before i connect the generator i'm going to install this panel cover back in here so that the interlock kit works properly because with the panel cover off that could allow a situation where you have both the utility turned on and the generator turned on at the same time which we do not want to do because i could backfeed the utility and we have our cord connected over there coming across the ground and over here to our generator we don't have it connected yet i'm just going to show you guys again that right now this is a an unbonded or floating neutral system so we have one prong in the neutral and then we'll just go ahead and check to ground and we do not have any continuity there so as soon as we plug in this cord though it will create continuity because it's essentially going to be connecting the ground and the neutral all the way back in that panel where you saw the both the ground and the neutral wire connected on the neutral bus so we have our plug so go ahead and test from the neutral which this one is connected to to the ground and you can see right there we have perfect continuity essentially now this generator is perfectly safe to use and is connected in the exact way that you would want it to be for a generator that's feeding through a power inlet box with a breaker interlock kit okay so to conclude we are going to go ahead fire up the generator and right now everything's set up with a floating neutral the way it's supposed to be and then we're going to use that appliance cord to essentially create a bonded neutral generator and we'll be able to measure how much current is actually flowing on the grounding conductor since this generator is connected to the very first panel i honestly don't think it's that big of a deal to have a bonded neutral generator connected and that's because you saw those two wires were connected right next to each other so basically the only place where you technically have current flowing on a ground wire where it's not supposed to be is on the cord going from your inlet box to the generator itself and even though that's technically not right technically we don't want any current flowing on the equipment grounding conductors it's in my opinion not that big of a deal but that's just my opinion always follow recommendations from manufacturers and any sort of instructions that are associated with your installation so let's go ahead and get this generator fired up we're gonna put the house load onto the generator and then we're going to measure how much current flows on that grounding conductor so we have our generator in volt mode we're going to turn the main breaker off for now it is connected to ground although it wouldn't have to be so we do have a ground rod connected i'll talk about that in a separate video but the short version is you don't really need a ground rod connected to your generator if you have it connected to your electrical system like we have here but again you're supposed to defer to manufacturer instructions which these chinese instructions say you're supposed to ground it so we're gonna go ahead and get it started up [Music] and then over at our panel we're gonna switch over to generator power so in order to do that we just have to turn off our main breaker feed in the property [Music] like that and then pull up our locking plate and turn on the generator now you heard the generator kick in there so we know that it is now supplying power to the property i'll grab my phone and we'll take a look at the sense energy monitor to see how much power is currently being drawn okay you can see right now we're using uh 485 watts so not a whole lot out of our total 3 500 ish watts that we could use so what we're going to do next is we're going to take our cord here that we were using earlier for simulating our our basically bonded generator and we're going to go ahead and connect this and then we're going to measure how much current is flowing basically on the grounding conductor instead of the neutral so go ahead and get that connected so plugging that in didn't change our wattage at all but now we probably have some power that is flowing on that ground wire so we'll go ahead and check that now so we have our meter and amps alternating current and now we can measure how much power is running through that ground wire so we have 0.16 amps running on the ground wire right now i think what i'm going to do is i'm going to turn on a couple more loads and see how that changes it [Music] so i turn on a few more loads and you can see right there we're drawing 1.28 amps that's flowing on our ground wire back to or i guess it's actually coming back to the generator it's coming back through there and ultimately combines on that neutral bar and comes back on both the brown wire and the neutral wire to the source which is what we're trying to avoid and that's why having a floating neutral is better for this particular situation i realized i didn't actually film a proper outro for this video so here we are it's the next day it's actually sunday morning right now father's day so happy father's day it is about 7 a.m you guys are going to be seeing this video a little bit later today but that pretty much summarizes the whole bonded versus unbonded neutral or floating neutral in generators so if you guys want to understand more about neutral current i made a video that kind of covers that pretty well so i'll put that link right here so you guys can see that it kind of goes through why neutrals and grounds are separated in sub panels and how you keep your neutral current from flowing on your equipment grounding conductors or if you want to see the video that youtube thinks you want to watch click on this video right down here thanks ton for watching you guys if this video earned your subscription make sure you hit that subscribe button and we will see you guys next week i think i'm gonna put up a video about

Channel: Benjamin Sahlstrom

Views: 124,938

Rating: 4.909091 out of 5

Keywords: manual transfer switch, floating neutral, emergency generator, emergency generators, generator question, floating neutral vs bonded neutral generator

Id: RkjjZJgaINA

Length: 27min 55sec (1675 seconds)

Published: Sun Jun 21 2020