1 00:00:05,879 --> 00:00:38,439 Ask What Up Up? Everybody? Welcome to another episode of Let's Ask Paul, 2 00:00:38,520 --> 00:00:45,399 the podcast where you get to submit questions to me using our free sponsored 3 00:00:45,600 --> 00:00:52,960 online portal sponsored by Wicks over at Paul Abernathy dot com. It's again we're 4 00:00:53,000 --> 00:00:58,799 not selling anything over there. It is a sponsored page that basically allows us 5 00:00:58,840 --> 00:01:02,640 to be able to have a uniformed way for you to send code questions and 6 00:01:02,840 --> 00:01:07,359 other questions into us, and it gets routed the proper way to a folder, 7 00:01:07,400 --> 00:01:11,959 which again keeps it from getting lost in the shuffle with the hundreds and 8 00:01:11,040 --> 00:01:15,120 hundreds of emails I get each week. It's just an easy way to get 9 00:01:15,159 --> 00:01:19,640 your questions to me and I'll answer either in an email or its selected in 10 00:01:19,680 --> 00:01:25,200 an upcoming podcast much like today's. And if you're not listening to our podcast 11 00:01:25,239 --> 00:01:26,920 so this is the first time you stumbled on it, Remember we have over 12 00:01:27,000 --> 00:01:34,159 eight hundred plus episodes going back quite a few years, and you can listen 13 00:01:34,200 --> 00:01:38,439 to all of them on any of your favorite podcasting platforms Sprinker, Spotify, 14 00:01:38,599 --> 00:01:45,040 Deezer, Apple Podcasts, Google Podcasts, Podban Gosh, there's so many way 15 00:01:45,079 --> 00:01:48,480 I listen on Spotify. It's my favorite platform to listen on and I also 16 00:01:48,519 --> 00:01:53,920 listen to my Alexa devices because I just asked for master the NEC podcast on 17 00:01:55,280 --> 00:01:59,439 the device and it'll play the latest episode. But if you want to dig 18 00:01:59,480 --> 00:02:04,200 deep into all of our episodes, some of them actually has descriptions. Others 19 00:02:04,200 --> 00:02:07,280 that are just mobile ones may not have a description. You just got to 20 00:02:07,280 --> 00:02:10,360 listen to them at random. But the easiest way to listen is to get 21 00:02:10,400 --> 00:02:15,120 our free mobile app. It's free, doesn't cost you anything, and we 22 00:02:15,199 --> 00:02:19,639 have a lot of free resources and tools on there for calculators and to use 23 00:02:19,719 --> 00:02:22,439 in the field. And it's neat to have on your phone. It's not 24 00:02:22,479 --> 00:02:25,599 going to take up any any space on your phone because it's a PWA app. 25 00:02:27,360 --> 00:02:31,319 But go check it out over on our website fast tracks system dot com, 26 00:02:31,360 --> 00:02:38,039 Fast t r X system dot com. Go check it out and it's 27 00:02:38,120 --> 00:02:42,879 free and it works on any of your mobile devices, tablets, and if 28 00:02:42,879 --> 00:02:45,159 you click on the link, it even works on a desktop. So it's 29 00:02:45,240 --> 00:02:49,400 pretty neat. And install it on your phone, do a shortcut to your 30 00:02:49,400 --> 00:02:53,199 homescreen, and if it asks you about notifications, absolutely select yes, because 31 00:02:53,199 --> 00:02:59,560 we send notifications from time to time updates and different things that are that are 32 00:02:59,599 --> 00:03:01,840 going on. We want to keep you aware of them. Maybe something drops 33 00:03:01,879 --> 00:03:07,199 that we think is interesting, like a new blog or a podcast or something. 34 00:03:07,479 --> 00:03:08,800 We want to keep you engaged. And again we're not going to take 35 00:03:08,840 --> 00:03:13,680 up any space on your phone, so go check that out. All right, 36 00:03:13,680 --> 00:03:17,759 today's episode, what's submitted And the question is, Paul, can you 37 00:03:17,879 --> 00:03:23,039 explain the application and changes that took place in the twenty twenty three n EC 38 00:03:24,080 --> 00:03:31,840 for permitted reductions for neutral conductors and prohibited reductions for neutral conductors and how they 39 00:03:31,840 --> 00:03:37,400 would apply to me in the field. Thanks again for all you do and 40 00:03:37,479 --> 00:03:42,719 appreciate listening to your podcasts on the job site and in the car from site 41 00:03:42,719 --> 00:03:47,000 to site. Well, thank you for listening. I'm glad you joined us 42 00:03:47,039 --> 00:03:51,400 and found our podcasts again. Remember, folks, you can listen to us 43 00:03:51,439 --> 00:03:55,120 from any of your favorite platforms and do me a favor. We don't advertise 44 00:03:55,159 --> 00:04:00,319 and we don't market. You need to share with other people. Let them 45 00:04:00,360 --> 00:04:02,560 know about a great podcast. It's available, and all they gotta do is 46 00:04:02,560 --> 00:04:11,199 search for Master the NEC podcast on all of their popular listening platforms and they 47 00:04:11,240 --> 00:04:14,000 can find us. Whatever they like to listen on, they can find us, 48 00:04:14,080 --> 00:04:15,800 or better yet, tell them about the app that they can download on 49 00:04:15,839 --> 00:04:20,040 their phone. Again, won't take up any space. Okay, So let's 50 00:04:20,079 --> 00:04:23,800 look at this question here. So the first thing we want to talk about 51 00:04:25,240 --> 00:04:28,879 is where do we go in the code? Now I'm in the twenty twenty 52 00:04:28,959 --> 00:04:33,399 three edition of the National Electrical Code, so that's what my response is going 53 00:04:33,439 --> 00:04:38,360 to be based on. So if you've got a twenty twenty three edition of 54 00:04:38,399 --> 00:04:41,199 the National Electrical Code, we're gonna go to to twenty dot sixty one. 55 00:04:41,240 --> 00:04:45,800 Now that part of it didn't change, right, that that's not any real 56 00:04:45,959 --> 00:04:50,399 change from the previous editions of the n EC, That that part didn't change. 57 00:04:50,439 --> 00:04:57,879 Okay, So just want to you know, make that clear how that 58 00:04:57,920 --> 00:05:02,040 worked out. Okay. Now, the only thing that really changes is in 59 00:05:02,079 --> 00:05:06,920 the twenty twenty three you're you have a two twenty six two one A, 60 00:05:08,800 --> 00:05:13,959 which is your basic calculation again not a change, and two twenty sixty one 61 00:05:14,040 --> 00:05:19,720 B, which is permitted reduction it. The only change in this really is 62 00:05:21,439 --> 00:05:28,279 giving some headings to what was B one and B two still the same, 63 00:05:28,879 --> 00:05:33,439 but now they've made it clear rather than writing in the language what it was 64 00:05:33,480 --> 00:05:38,000 all about, like cooking wall, amount of oven or whatever, it now 65 00:05:38,079 --> 00:05:42,120 has a kind of a heading to it. So there's a B one and 66 00:05:42,160 --> 00:05:45,800 a B two, same as it was before, but now it kind of 67 00:05:45,800 --> 00:05:48,079 gives you a heads up. It says B one is where household electric ranges 68 00:05:48,079 --> 00:05:51,759 wall amount of ovens, counter amount of cooking units and dryers, right, 69 00:05:53,079 --> 00:06:00,879 very specific, and then B two is unbalanced load in excess of two hundred 70 00:06:00,920 --> 00:06:06,120 amps. All right, So it's just a structural change. It's not anything 71 00:06:06,879 --> 00:06:12,480 that's critically changed that's going to be too confusing. It's just kind of how 72 00:06:12,519 --> 00:06:16,279 it structurally went. And then of course you have two twenty sixty one, 73 00:06:16,399 --> 00:06:27,920 see which is the prohibited reductions. And again so not any really change in 74 00:06:27,959 --> 00:06:32,439 that that's substant substantive. That's too much that's going to cause any confusion with 75 00:06:32,480 --> 00:06:38,759 anybody. So again, now the only other thing is that I believe, 76 00:06:40,279 --> 00:06:46,879 let's see here now, nothing additional that's worthy of me talking about any change 77 00:06:46,920 --> 00:06:48,879 when it comes to this. So so the reason I bring all that up 78 00:06:49,639 --> 00:06:55,720 because there is a wording change that has been changed in here that I'm going 79 00:06:55,759 --> 00:06:59,560 to address. But I just wanted to make sure that everybody following along realizes 80 00:06:59,600 --> 00:07:01,120 that whether you're following in the twenty twenty or the fact that I'm in the 81 00:07:01,120 --> 00:07:06,720 twenty twenty three, it doesn't mean you can't. What I'm going to talk 82 00:07:06,720 --> 00:07:11,160 about the day is not Germane to you. It doesn't matter which cycle you're 83 00:07:11,199 --> 00:07:15,120 in, right, it's going to be Germane either way. Okay, all 84 00:07:15,199 --> 00:07:19,519 right, so let's kind of dig into this, all right, So right 85 00:07:19,560 --> 00:07:25,759 off the bat, let me tell you the change that is significant. Now, 86 00:07:25,800 --> 00:07:30,000 when we did permitted reductions like this is where we took a neutral and 87 00:07:30,120 --> 00:07:36,959 we could reduce the size of the neutral. It used to say that when 88 00:07:38,000 --> 00:07:42,160 you permitted reduction there was an or in there when it was considering between two 89 00:07:42,160 --> 00:07:44,680 twenty six two one B one and B two. So B one was the 90 00:07:44,800 --> 00:07:48,759 ranges and dryers and whatnot reduction, and then the two the B two was 91 00:07:48,800 --> 00:07:51,399 the portion it was over two hundred amps. Now in that it used to 92 00:07:51,439 --> 00:07:56,240 be or. So it made it imply that it had you had to pick 93 00:07:56,800 --> 00:08:00,680 whether or not you're going to apply the seventy percent to the cooking equipment, 94 00:08:00,680 --> 00:08:05,279 for example, or the dryer. That if you did that, then if 95 00:08:05,319 --> 00:08:11,399 your neutral loads were over two hundred amps overall unbalanced load that you couldn't apply 96 00:08:11,519 --> 00:08:13,439 B two as well. It's kind of like an oor, you had to 97 00:08:13,439 --> 00:08:16,759 pick one or the other. Well, that's changed for the twenty twenty three 98 00:08:16,879 --> 00:08:22,959 because you could apply both that you could have. Obviously, a neutral reduction 99 00:08:22,079 --> 00:08:28,279 can apply to your neutral calculation for ranges and dryers, for example. But 100 00:08:28,480 --> 00:08:33,600 also if you're overall unbalanced neutral load based on a calculation is over two hundred, 101 00:08:33,679 --> 00:08:37,399 then you ought to be able to apply B two as well for that 102 00:08:37,919 --> 00:08:43,480 unbalanced load in excess of two hundred amp years. Okay, And so that's 103 00:08:43,519 --> 00:08:46,879 what we're kind of going to look at look at today and how that would 104 00:08:46,919 --> 00:08:54,759 apply. Now, it wouldn't be right for us to not at least explain 105 00:08:54,639 --> 00:09:00,679 what a prohibited reduction is. So obviously we're going to show you how do 106 00:09:00,720 --> 00:09:05,440 you apply that seventy percent and where you wouldn't where you wouldn't. But in 107 00:09:05,679 --> 00:09:09,440 the prohibited reduction, which is two twenty sixty one C, we're going to 108 00:09:09,519 --> 00:09:16,360 show you an example of where you're going to have to dissect out a certain 109 00:09:16,480 --> 00:09:22,320 value for a let's say, a non linear load that you're not allowed to 110 00:09:22,399 --> 00:09:28,240 apply the reduction too. And so people do ask, how do you dissect 111 00:09:28,279 --> 00:09:30,960 this out? So that's what we're going to kind of do today in some 112 00:09:31,039 --> 00:09:33,360 examples for you. Okay, we're gonna give you two examples. First example 113 00:09:33,399 --> 00:09:39,159 is going to be just a normal load CALCU wherever the system may be delta. 114 00:09:39,960 --> 00:09:45,720 In this case, you have all linear loads, normal loads. There's 115 00:09:45,759 --> 00:09:48,840 nothing you have to worry about except we're doing your calculation and you come up 116 00:09:48,879 --> 00:09:54,519 with your maximum unbalanced load based on your calculation. Okay, so let's look 117 00:09:54,559 --> 00:10:00,759 at it. So when we look at the rules, we're going to focusing 118 00:10:00,799 --> 00:10:07,159 today on two twenty sixty one B two. All right, and this is 119 00:10:07,200 --> 00:10:13,399 for the unbalanced load in excess of two hundred am piers. Now, if 120 00:10:13,440 --> 00:10:18,120 you do a load calculation and your load, whether it's a single family dwelling, 121 00:10:18,240 --> 00:10:24,200 multifamily dwelling, whatever it is, if your neutral loads exceed two hundred 122 00:10:24,240 --> 00:10:30,320 am piers, then you're able to do a reduction. And it's going to 123 00:10:30,399 --> 00:10:33,279 tell you which ones, which systems you can do this on. Okay, 124 00:10:33,320 --> 00:10:35,840 And then the course the prohibitive reduction is going to tell you what systems you 125 00:10:35,919 --> 00:10:41,840 can't do this on or what condition your situation is that you can't reduce it. 126 00:10:43,000 --> 00:10:48,000 Okay, So in our situation, I'm gonna give you two, all 127 00:10:48,039 --> 00:10:54,399 right. So the first one just a normal, normal application and and we'll 128 00:10:54,399 --> 00:11:00,559 show you an example, and then i'll explain which systems you're not allowed to 129 00:11:00,679 --> 00:11:03,000 reduce the neutral load. Okay, all right, So the first example I'm 130 00:11:03,000 --> 00:11:07,000 gonna give you, it's just a you did a calcu You did a calculation, 131 00:11:07,039 --> 00:11:11,039 and you came up with four hundred amps of maximum unbalanced load. You 132 00:11:11,120 --> 00:11:15,759 just did a standard calculation, because you remember to twenty sixty one is in 133 00:11:15,840 --> 00:11:20,799 Part three, which is a standard method. Right, So even if you 134 00:11:20,879 --> 00:11:26,840 do an optional method calculation under Part four when you're sizing the neutrals, you're 135 00:11:26,840 --> 00:11:31,679 still going to be using Part three, right, So always good to think 136 00:11:31,679 --> 00:11:33,840 that if you're in the field, you're thinking, well, I would never 137 00:11:33,919 --> 00:11:39,399 calculate anything using the standard method, but you're going to unless you just make 138 00:11:39,440 --> 00:11:43,159 the neutrals full size and don't want to do a calculation, then you're going 139 00:11:43,240 --> 00:11:46,960 to you know, you're gonna be in Part three. So you need to 140 00:11:46,039 --> 00:11:48,679 learn how to use it, okay. And anybody out there that tells you 141 00:11:48,679 --> 00:11:52,200 you don't, don't trust them, and that's not an educator you want to 142 00:11:52,240 --> 00:11:58,480 learn from. You need to learn part three and part four of calculations. 143 00:11:58,759 --> 00:12:03,279 Right, Okay, so let's kind of look at our scenarios. So we've 144 00:12:03,320 --> 00:12:07,039 got a load. We did our calc and we have four hundred amps of 145 00:12:07,120 --> 00:12:13,480 unbalanced current. That's our neutral current. So in applying to twenty sixty one 146 00:12:13,600 --> 00:12:16,720 B two, and here's what the code says. This say is that portion 147 00:12:18,559 --> 00:12:22,480 of the unbalanced load in excess of two hundred amp piers. So that means 148 00:12:22,480 --> 00:12:26,480 the first two hundred ampiers is at one hundred percent, right, Because we're 149 00:12:26,480 --> 00:12:31,879 talking about the amount over two hundred amps where the feeder or service is supplied 150 00:12:31,559 --> 00:12:41,919 from a three wire DC or single phase AC system, a four wire three 151 00:12:41,000 --> 00:12:48,480 phase system, a three two phase system, or a five wire two phase 152 00:12:48,559 --> 00:12:52,080 system. And again two phase systems in whether it's a three wire or a 153 00:12:52,159 --> 00:12:56,879 five wire are rare. I'm not going to cover those, but the key 154 00:12:56,960 --> 00:13:03,600 here is single phase or even a four wire three phase system, you can 155 00:13:03,639 --> 00:13:09,360 reduce the size of the neutral that exceeds two hundred amps. Okay, so 156 00:13:09,399 --> 00:13:13,080 the first two hundred one hundred percent. Just take the first two hundred and 157 00:13:13,120 --> 00:13:16,879 that's a given. Anything over that you can reduce it seventy percent. Now, 158 00:13:16,879 --> 00:13:20,039 where do we get that rule? At the very beginning of two twenty 159 00:13:20,279 --> 00:13:24,080 sixty one B it says that the feeder a service and feeder supplying the following 160 00:13:24,120 --> 00:13:31,080 loads shall be permitted to have an additional demand factor of seventy percent applied to 161 00:13:31,159 --> 00:13:35,960 the amount in to twenty sixty one B one, And that's the value for 162 00:13:35,080 --> 00:13:39,000 like ranges, wall amount, ovens, whatever. And then it says, 163 00:13:39,080 --> 00:13:43,679 and a portion of the amount in two twenty dot sixty one B two, 164 00:13:43,720 --> 00:13:48,759 which is the value that exceeds two hundred of unbalanced load. Right now, 165 00:13:50,320 --> 00:13:54,480 that change took place in the twenty twenty three again where it says and whereas 166 00:13:54,480 --> 00:13:58,440 in the twenty twenty it said or so it was almost made you feel like 167 00:13:58,440 --> 00:14:01,480 you had to pick one or the other, and that wasn't the intent. 168 00:14:03,279 --> 00:14:07,000 Both of them were applicable. So I can apply the seventy percent to my 169 00:14:07,120 --> 00:14:11,039 range, my range for the service calc. But also at the end, 170 00:14:11,200 --> 00:14:18,679 I can do an additional reduction on that neutral overall if it exceeds two hundred 171 00:14:18,720 --> 00:14:22,679 amp years. Okay, Now, most one and two families are probably not 172 00:14:22,799 --> 00:14:28,279 going to have two hundred amps of maximum unbalanced load, right, so that's 173 00:14:28,360 --> 00:14:31,600 not going to be an issue anyway, okay, but just so you know 174 00:14:31,639 --> 00:14:35,399 how it applies. So let's look at our example. We had four hundred 175 00:14:35,399 --> 00:14:41,480 amps of unbalanced current. To say it's a single phase ac perfectly easiest way 176 00:14:41,519 --> 00:14:46,200 to approach it, and it is two hundred amps. The first two hundred 177 00:14:46,200 --> 00:14:48,799 obviously one hundred percent because we're worried about that portion that's over two hundred, 178 00:14:50,039 --> 00:14:52,639 and that was another two hundred, right because we said it was four hundred 179 00:14:52,679 --> 00:14:56,360 overall. You take that portion that's over two hundred within our cases, another 180 00:14:56,440 --> 00:15:01,399 two hundred. You multiply that by seventy p sent and that is going to 181 00:15:01,440 --> 00:15:05,399 be one hundred and forty. Am piers Well, you take that one forty 182 00:15:05,519 --> 00:15:09,279 and you're going to add it back to the two hundred, which you took 183 00:15:09,279 --> 00:15:11,919 it one hundred percent, and that's going to give you a total of three 184 00:15:11,000 --> 00:15:16,120 hundred and forty Am Piers Well, that's going to be your maximum unbalanced load 185 00:15:16,159 --> 00:15:20,080 that you have calculated and you have applied the demands, and now you're going 186 00:15:20,120 --> 00:15:24,559 to size your conductors accordingly. You're you're grounded neutral conductor accordingly, okay, 187 00:15:26,519 --> 00:15:31,000 straightforward, and that's the additional reduction that you can do, and remember that 188 00:15:31,080 --> 00:15:39,759 is applicable in all situations, whether it's optional or standard. However, you're 189 00:15:39,799 --> 00:15:45,840 gonna have to go and do the neutral calculation right now. A lot of 190 00:15:45,879 --> 00:15:52,879 times people forget that you have two fifty one zero two C one, which 191 00:15:52,960 --> 00:15:56,279 is titled grounded conductor. So it can't be any smaller than what's in that 192 00:15:56,399 --> 00:16:02,080 table. So you need to always check the size that you calculate with the 193 00:16:02,159 --> 00:16:06,679 minimum size and that table, and remember that it can't be it can't be 194 00:16:06,879 --> 00:16:10,240 smaller than what's in that table. In our case, it's gonna be larger 195 00:16:10,279 --> 00:16:12,080 because now we have to size the neutral for that three hundred and forty am, 196 00:16:12,159 --> 00:16:15,519 so it's definitely going to be greater than whatever it would be in that 197 00:16:15,639 --> 00:16:22,240 table. Okay, okay, And so at the end of the day, 198 00:16:22,799 --> 00:16:26,000 we need three hundred forty AM years and we're going to size the conductors accordingly. 199 00:16:26,159 --> 00:16:33,879 Now, let's look at the prohibited reductions really quickly. Okay. Now 200 00:16:34,279 --> 00:16:41,840 here's the prohibited when you cannot, okay, reduce a certain portion of that 201 00:16:41,200 --> 00:16:45,320 unbalanced load when it comes to the neutral, right, all right, So 202 00:16:45,600 --> 00:16:49,960 let's look at that prohibited reduction. So this is two twenty sixty one C 203 00:16:51,720 --> 00:16:57,120 and it says there shall be no reduction of the neutral or grounded conductor capacity 204 00:16:57,320 --> 00:17:07,359 applied to the amount in two twenty sixty one C one, or portion of 205 00:17:07,480 --> 00:17:15,279 the amount in C two from that determined by the basic calculation. So what 206 00:17:15,440 --> 00:17:18,559 that means is, if we have a certain value that we calculated out of 207 00:17:18,880 --> 00:17:23,240 unbalanced current, if there's a certain portion of that that falls under the two 208 00:17:23,279 --> 00:17:29,160 items of prohibitive reduction that we're going to talk about, then that portion cannot 209 00:17:29,240 --> 00:17:33,839 be reduced. Just that portion cannot be reduced, Okay, So let's look 210 00:17:33,880 --> 00:17:38,400 and see overall when we can't apply a reduction, all right, So the 211 00:17:38,480 --> 00:17:42,759 first one we'll look at. It says number one. So C one says 212 00:17:42,920 --> 00:17:51,079 any portion, okay, any portion of a three wire circuit consisting of two 213 00:17:51,279 --> 00:17:57,440 un grounded conductors and the neutral conductor of a four wire three phase y connected 214 00:17:57,519 --> 00:18:02,200 systems. So if I'm having a four wire three phase y connect the system, 215 00:18:02,240 --> 00:18:04,559 and I'm going to derive from it, make connections to it, and 216 00:18:04,640 --> 00:18:10,200 I'm going to be deriving a three wire circuit from a four wire circuit, 217 00:18:11,000 --> 00:18:17,759 and it's a three phase y system that we're starting out with and I'm connecting 218 00:18:17,799 --> 00:18:22,640 onto it to create a three wire circuit that's gonna have again two hots and 219 00:18:22,680 --> 00:18:29,839 a neutral, then I am not allowed to apply a reduction to the neutral. 220 00:18:32,079 --> 00:18:37,279 Calculation that is going to be whatever is being supplied by that three wire 221 00:18:37,599 --> 00:18:41,519 circuit that's deriving from that four wire three phase y circuit. You get me. 222 00:18:41,880 --> 00:18:45,119 It's you're just not going to have to be able to do to reduce. 223 00:18:45,160 --> 00:18:48,720 So whatever that might be feeding. Let's say it's feeding a panel and 224 00:18:48,920 --> 00:18:53,079 it's again for lack of a better example, tapping it off or connecting or 225 00:18:53,160 --> 00:18:57,920 bugging onto a four wire three phase y in order to get that three wire 226 00:18:59,599 --> 00:19:03,119 two high it's in a neutral, then you're not going to be able to 227 00:19:03,200 --> 00:19:07,039 reduce the neutral that's being supplied from that. Okay, So that's the first 228 00:19:07,079 --> 00:19:12,559 one. No reduction allowed. So that neutral that's that's running with those three 229 00:19:12,640 --> 00:19:17,519 wires, that two wires, and that neutral that's being fed from that four 230 00:19:17,559 --> 00:19:22,319 wire three phase yre wherever that's going, there is going to be no reduction 231 00:19:22,160 --> 00:19:26,519 on that neutral when we do that calculation for whatever that supplies panel or whatever 232 00:19:26,599 --> 00:19:33,839 it may be supplying. Okay, So no reduction on that portion now when 233 00:19:33,880 --> 00:19:41,799 it comes to C two, it says that portion consisting of non linear loads 234 00:19:41,000 --> 00:19:48,880 supplied from a four wire why connected three phase system. Okay, okay, 235 00:19:48,079 --> 00:19:57,000 So let's do an example where we have some nonlinear current. We have a 236 00:19:57,119 --> 00:20:03,160 four wire why connect the three phase system, and we have a total neutral 237 00:20:03,200 --> 00:20:07,480 load folks, of six hundred ninety amps on this example, six hundred ninety 238 00:20:07,480 --> 00:20:12,160 amps. Okay, and that's the total that is our unbalanced current. We 239 00:20:12,240 --> 00:20:17,279 did the calc. That's is what it is. But of that value, 240 00:20:17,920 --> 00:20:23,799 two hundred and fifty amps of that six ninety actually is considered nonlinear current. 241 00:20:26,079 --> 00:20:30,640 Okay. Well, now we have a problem. But we all we can 242 00:20:30,839 --> 00:20:37,200 only not apply the reduction to that portion that has the non linear loads. 243 00:20:37,359 --> 00:20:41,160 For the rest of this is obviously linear loads, okay, normal lamping, 244 00:20:41,319 --> 00:20:47,680 normal lighting systems, normal motor, normal loads. They're not considered nonlinear. 245 00:20:48,279 --> 00:20:51,920 Now what are non linear loads? By the way, these are things that 246 00:20:52,039 --> 00:20:55,759 really are going to distort the normal sin your sort of waveform kind of causes 247 00:20:55,839 --> 00:21:00,839 a disruption. You don't get neutral cancelation very easily. Things like computers, 248 00:21:00,880 --> 00:21:06,839 variable frequency drives, switching devices, printers, copy machines, big office buildings 249 00:21:06,880 --> 00:21:10,039 with a lot of electronic balance. All those type of things will chop the 250 00:21:10,160 --> 00:21:14,519 crap out of a normal waveform, and it's hard for neutral cancelization. When 251 00:21:14,599 --> 00:21:18,440 the waveform gets chopped like that, it's not a nice flow. Like you 252 00:21:18,519 --> 00:21:22,400 might look into the sillioscope and it looks like a normal, nice waveform. 253 00:21:22,559 --> 00:21:26,160 It chops it up and it's hard to If you think about when we talk 254 00:21:26,240 --> 00:21:32,839 about neutral loads. If i have a multi wire brand circuit and I'm putting 255 00:21:32,880 --> 00:21:34,599 it in a panel and I'm sharing a neutral for example, right we just 256 00:21:34,640 --> 00:21:38,559 say single phase, just for simplicity sake. If I have ten amps on 257 00:21:40,039 --> 00:21:45,440 leg one and ten amps on leg two, because of the cancelation effect, 258 00:21:45,519 --> 00:21:49,880 the neutral will see zero. If I have ten on one and eight on 259 00:21:49,960 --> 00:21:52,720 the other, the neutral will see the imbalance, which is two amps. 260 00:21:53,000 --> 00:22:00,160 Okay, this is what the neutral will see. Now, what happens in 261 00:22:00,440 --> 00:22:04,720 a situation we have a lot of harmonics or you have non linear loads that 262 00:22:04,960 --> 00:22:11,039 is not an each a nice cancelation effect process. It doesn't take place as 263 00:22:11,119 --> 00:22:15,839 nice and smooth as what we just said. So the neutral current could be 264 00:22:15,960 --> 00:22:18,440 as much as or equal to any of the phase conductors, depending on the 265 00:22:18,480 --> 00:22:22,960 system, so it can be problematic. And this is why you might see 266 00:22:23,279 --> 00:22:30,279 four wire three phase systems with these non linear loads. You might see situations 267 00:22:30,319 --> 00:22:34,319 where you see white conductors that are turning brown or whatnot, and they weren't 268 00:22:34,359 --> 00:22:40,599 sized properly, right, I just say they just as an example, all 269 00:22:40,640 --> 00:22:44,160 right. So what we've got is we did a calculation six hundred ninety amps 270 00:22:44,359 --> 00:22:48,119 and two hundred and fifty amps of that we know is nonlinear current, all 271 00:22:48,200 --> 00:22:52,400 right, So how do we apply the rules here? Probably just as straightforward 272 00:22:52,440 --> 00:22:56,119 as you can imagine. The first two hundred amps, is it one hundred 273 00:22:56,119 --> 00:23:02,400 percent? And then you have the non any your current, which you have 274 00:23:02,559 --> 00:23:06,359 to take out because we can apply the reduction to that amount. So that's 275 00:23:06,400 --> 00:23:07,720 at one hundred percent. So you have the two hundred amps that we have 276 00:23:07,799 --> 00:23:12,000 to take it one hundred that we can't apply reduction two, right, And 277 00:23:12,079 --> 00:23:18,240 then we have the non linear current that we can't apply the reduction too because 278 00:23:18,480 --> 00:23:22,519 of to twenty dot sixty one C two. Okay, that portion that is 279 00:23:22,599 --> 00:23:26,720 nonlinear, so I take that out, no reduction there, and so you 280 00:23:26,839 --> 00:23:30,319 take that six ninety and you take away two hundred and take away two fifty 281 00:23:30,559 --> 00:23:34,640 that leaves me two hundred and forty amps. That's the portion that we can 282 00:23:36,359 --> 00:23:41,200 apply. Okay, the reduction two under to twenty sixty one B two, 283 00:23:42,079 --> 00:23:47,359 So we just take that two forty, we multiply that by seventy percent. 284 00:23:47,880 --> 00:23:52,079 That's one hundred and sixty eight amps. But then we apply that back to 285 00:23:52,240 --> 00:23:53,920 that first two hundred that we have to take it one hundred percent. And 286 00:23:55,000 --> 00:23:57,720 of course we got to apply to that non linear load, which we can't 287 00:23:57,759 --> 00:24:03,440 take a reduction four. Right, we already saw that C two tells us 288 00:24:03,480 --> 00:24:07,359 we can't, so we add that back. So it's two hundred plus two 289 00:24:07,440 --> 00:24:11,480 fifty plus are one sixty eight that we did apply the seventy percent too. 290 00:24:11,200 --> 00:24:15,920 That means the total demand that we've calculated out is six hundred and eighteen amps 291 00:24:15,960 --> 00:24:21,200 of neutral load. Now six hundred and eighteen amps is a reduction from six 292 00:24:21,440 --> 00:24:26,880 ninety and you know what, it could be a conductor size change. But 293 00:24:26,039 --> 00:24:30,480 this is how it applies, and that's how you're going to apply to twenty 294 00:24:30,759 --> 00:24:36,319 sixty one B one. Excuse me B two for the excess of two hunt 295 00:24:36,400 --> 00:24:41,240 over that exceeds two hundred amps, and how you're going to apply through prohibited 296 00:24:41,079 --> 00:24:48,160 reductions. Okay, and those were two examples that you know pretty much show 297 00:24:48,200 --> 00:24:52,599 you how you would do that. Hopefully that that kind of makes sense right 298 00:24:52,960 --> 00:24:55,960 to everybody out there, all right, So if I ask you a question 299 00:24:56,599 --> 00:25:00,880 and I'll create a scenario for you that allows us to apply what we've just 300 00:25:02,039 --> 00:25:06,319 learned. Okay, So the very first one, let's look at a question. 301 00:25:06,480 --> 00:25:11,920 So straightforward, I'm only going to tell you the question, and you're 302 00:25:11,000 --> 00:25:15,920 gonna have to assume that none of the prohibitive reductions apply because I didn't state 303 00:25:15,039 --> 00:25:18,920 that they do, but I will give you an example when it does. 304 00:25:18,440 --> 00:25:22,799 So this is a question, is what is the neutral demand? If the 305 00:25:22,000 --> 00:25:27,200 unbalanced current of a neutral is five hundred and sixty six ams. So we'll 306 00:25:27,240 --> 00:25:32,720 assume it's a single phase because nobody said said otherwise. Or we'll assume it's 307 00:25:32,759 --> 00:25:38,119 maybe a three phase system four wire that wasn't that didn't have non linear loads, 308 00:25:38,839 --> 00:25:45,519 right, So obviously we can apply the reduction here. So let's look 309 00:25:45,559 --> 00:25:49,240 at it. So five hundred and sixty six AMS is the unbalanced load that 310 00:25:49,279 --> 00:25:53,200 we're given based on our calculations, you know, standard method, we calculated 311 00:25:53,240 --> 00:26:02,279 it out. So the rule here in twenty dot sixty one B two allows 312 00:26:02,359 --> 00:26:07,000 me to apply the seventy percent to that portion that exceeds two hundred amps. 313 00:26:07,119 --> 00:26:11,160 So that five hundred and sixty six we're gonna take two hundred away, which 314 00:26:11,160 --> 00:26:12,279 is going to be a one hundred percent because we're gonna add that back at 315 00:26:12,319 --> 00:26:15,480 the end, and that gives me three hundred and sixty six amps. That 316 00:26:15,599 --> 00:26:21,240 is the portion that is over two hundred that's the portion that we're going to 317 00:26:21,279 --> 00:26:25,920 apply the seventy percent too. So I'm going to multiply that by point seven 318 00:26:26,039 --> 00:26:30,319 zero, and that is two hundred and fifty six point two amp years. 319 00:26:30,039 --> 00:26:34,160 Right now, I get to drop the point two because as it says in 320 00:26:34,240 --> 00:26:37,680 two twenty five, okay, that portion, we get to drop it. 321 00:26:37,759 --> 00:26:40,559 If you want to keep it, it's not going to make a difference in 322 00:26:40,599 --> 00:26:44,720 your equation, right But again, you can do it at the end, 323 00:26:44,839 --> 00:26:47,359 or you can do it here. You can even keep it. That point 324 00:26:47,440 --> 00:26:51,599 two is not going to play a role anywhere. So in our case, 325 00:26:52,039 --> 00:26:55,200 we're gonna take that two hundred and fifty six point two if you would like, 326 00:26:56,319 --> 00:27:00,559 and add that back to the original two hundred and that equals fourn Er 327 00:27:00,640 --> 00:27:04,519 fifty six point two. I'm going to drop the point two and it's gonna 328 00:27:04,519 --> 00:27:11,000 be fourn Er fifty six, and I'm gonna size my conductor accordingly. Right, 329 00:27:12,240 --> 00:27:17,039 So this is sizing the neutral for the service. Keep this in mind 330 00:27:17,079 --> 00:27:18,519 that if you're doing a brand circuit and you get a question on an exam 331 00:27:18,640 --> 00:27:23,960 that wants to know what the actual contribution is for the neutral, then all 332 00:27:23,960 --> 00:27:27,599 you're gonna answer that is by giving the exact value, not rounding it. 333 00:27:27,799 --> 00:27:33,440 Just the exact value. Here we're talking about a service calculation, so we're 334 00:27:33,519 --> 00:27:38,400 going to be rounding and those type of things again. But just keep that 335 00:27:38,480 --> 00:27:41,599 in mind. If you want to use the total value, that's that's fine. 336 00:27:41,799 --> 00:27:47,039 But in this case, since it was less than point five, then 337 00:27:47,079 --> 00:27:48,400 we're gonna we dropped it off, so that was four or fifty six. 338 00:27:48,480 --> 00:27:52,160 So size your neutral conductor accordingly. Again, can't be smaller than what's given 339 00:27:52,200 --> 00:27:56,359 in two fifty one zero two c one, but in this case it's obviously 340 00:27:56,440 --> 00:27:59,839 going to be larger. So we're okay there. Now, what if I 341 00:28:00,039 --> 00:28:03,480 ask you this question. We'll use the same amp values, but now I 342 00:28:03,720 --> 00:28:11,160 tell you that two hundred amps of that six ninety I'm excuse me, two 343 00:28:11,279 --> 00:28:17,000 hundred amps. So that five to sixty six is non linear loads. Now, 344 00:28:17,079 --> 00:28:22,799 remember prohibited in two twenty sixty one C says that that portion of it 345 00:28:22,400 --> 00:28:30,640 of the neutral that is non linear, you cannot apply the seventy percent to 346 00:28:30,759 --> 00:28:33,400 it. Okay, So that tells us that we just got to exclude that 347 00:28:33,599 --> 00:28:38,039 from the equation. So let's do it. So the same values five hundred 348 00:28:38,039 --> 00:28:44,119 and sixty six amps of our calculated what we've calculated out to be our neutral 349 00:28:44,160 --> 00:28:47,720 loads. And so I'm going to take that five sixty six. I'm gonna 350 00:28:47,720 --> 00:28:49,480 subtract away two hundred because we know the first two hundred has to be one 351 00:28:49,559 --> 00:28:52,880 hundred percent anyway, So that's two hundred. So we're just gonna put that 352 00:28:52,960 --> 00:28:56,720 aside. And so we do that, and what does that leave us? 353 00:28:57,119 --> 00:29:02,480 Okay, So we take the five six six minus two hundred, that equals 354 00:29:02,519 --> 00:29:06,960 three hundred and sixty six. Now, remember what we said, two hundred 355 00:29:07,200 --> 00:29:14,680 of that five sixty six is also non linear loads. So we're gonna take 356 00:29:14,759 --> 00:29:18,640 away two hundred from this three sixty six as well. So we're gonna take 357 00:29:18,640 --> 00:29:23,200 two hundred away from that. That leaves us with one sixty six of load 358 00:29:23,480 --> 00:29:27,680 neutral load that we can now apply the seventy percent. To remember, the 359 00:29:27,720 --> 00:29:33,599 first two hundred one hundred percent got to take the full two hundred the amount 360 00:29:33,759 --> 00:29:37,319 over that you can apply the seventy percent. But remember we cannot apply it 361 00:29:37,839 --> 00:29:44,319 to those non linear loads. So what we've got is, let's recap. 362 00:29:44,640 --> 00:29:48,440 We have five sixty six minus two hundred. That's the first two hundred minus 363 00:29:48,599 --> 00:29:52,000 another two hundred for those non linear loads. So we were taking into consideration 364 00:29:52,079 --> 00:29:56,720 that gave us one sixty six. We multiply that by seventy percent. That 365 00:29:56,799 --> 00:30:00,519 gives us one hundred and sixteen point two. You can drop the point two 366 00:30:00,559 --> 00:30:03,359 if you choose at this point, or carry it on and go on through 367 00:30:03,400 --> 00:30:06,880 the math. But now I've got to add back the two hundred of the 368 00:30:06,960 --> 00:30:11,119 original two hundred, and I have to add that two hundred back of that 369 00:30:11,319 --> 00:30:15,960 non linear load that we couldn't reduce. So it's one sixteen point two plus 370 00:30:17,079 --> 00:30:21,640 two hundred plus two hundred equals five hundred and sixteen point two. I can 371 00:30:21,759 --> 00:30:23,480 drop the point two if you would like, and that is five hundred and 372 00:30:23,559 --> 00:30:29,920 sixteen amps of now neutral load. And again that point two is the actual 373 00:30:30,160 --> 00:30:33,839 value. It's not going to change the value at the end of the day. 374 00:30:33,359 --> 00:30:38,839 Okay, so you're going to size the conductors accordingly to handle that maximum 375 00:30:38,880 --> 00:30:44,519 and balanced load. After we've applied what we could do a reduction on and 376 00:30:44,680 --> 00:30:48,319 also what we could not do a reduction on. And so that's exactly how 377 00:30:48,400 --> 00:30:55,119 we work that entirely based on those two given examples. Okay, all right, 378 00:30:55,119 --> 00:30:56,400 folks, hopefully got something out of that. Those are kind of two 379 00:30:56,440 --> 00:31:00,000 examples and it kind of mixes with the whole lesson that we did today. 380 00:31:00,400 --> 00:31:06,279 Hopefully that answers the gentleman's question on derating the neutral when you can, when 381 00:31:06,319 --> 00:31:10,640 you can't, and then how you would apply it if you have both nonlinear 382 00:31:11,359 --> 00:31:17,000 and you have linear loads and a calculation what you reduce the neutral buy and 383 00:31:17,160 --> 00:31:21,039 how you use these different rules and it's a little clearer for you. Again, 384 00:31:21,039 --> 00:31:22,359 if you want to learn more about the National Eletrical Code, we encourage 385 00:31:22,359 --> 00:31:26,720 you to check out our website fast track system dot com. We have some 386 00:31:26,799 --> 00:31:30,039 great blogs on there that are free. Get our free mobile app from the 387 00:31:30,079 --> 00:31:33,319 website as well, a lot of calculators in there to make life just so 388 00:31:33,440 --> 00:31:37,400 much easier out in the field, we're constantly adding new things. If you 389 00:31:37,480 --> 00:31:41,039 want to get a great course on the Nationalletrical Code, check out our courses 390 00:31:41,079 --> 00:31:45,079 and our fast tracks program over on fastracksystem dot com. And if you got 391 00:31:45,079 --> 00:31:48,480 any questions, please, by all means feel free to ask them at Paul 392 00:31:48,519 --> 00:31:52,279 Abernathy dot com through the portal and we'll be happy to answer any of those 393 00:31:52,359 --> 00:31:55,920 for you. All right, folks, Until next time, stay safe, 394 00:31:56,319 --> 00:32:25,039 God bless and keep learning. Both ask both as both ask no f