Understanding System Voltages, NEC 2020, (46min:29sec)

In this video, we’ll explain the theory behind system voltages and how they relate to the nominal voltage requirements for the proper operation of electrical equipment. We will also explain what might happen if we don’t follow NEC bonding and grounding requirements for separately derived systems.
This video is extracted from Mike Holt’s Understanding the 2020 National Electrical Code Complete Training Library. To learn more visit www.MikeHolt.com/Code or call 888.632.2633.
For over 40 years, Mike Holt Enterprises has been providing quality electrical code training to help electrical professionals learn the Code, prepare for exams, and improve their electrical knowledge. Visit www.MikeHolt.com for exam preparation tips and training, instructor and curriculum support, continuing education options, free videos and graphics, and so much more.

[@Nahum17good]

Not only do you inspire me to be a better electrician, but you also inspire me to be a better person! God bless you and your family.

[@MikeHoltNEC]

What a lovely message, thank you.

[@QuaabQueb]

<a href="#" class="seekto" data-time="1060">17:40</a> this is the type of energy and personality that makes a truly great teacher, a person so filled with not only the knowledge but also the drive, the passion and the overwhelming excitement to tell it to others.

[@MikeHoltNEC]

Thank you, I did get excited...

[@noahmchugh3769]

Mike, I’m a 3rd year apprentice and I’ve heard your name a couple times and this is the first video of yours I’m watching and my first impression of you is excellent. What set that is how you start by giving our Father in heaven the glory.

[@4eightyvolt]

For those confused the illustration @ <a href="#" class="seekto" data-time="180">3:00</a> is a typo. The primary should be "480/20 turns = 24v per turn" and the secondary should be "24v per turn x 5 turns = 120v". Mr. Holt explains it correctly though. Just fyi

[@MikeHoltNEC]

Thanks...

[@lawtonsegler1923]

Regarding three phase autotransformers, I worked for an OEM that manufactured large three phase motor operated equipment that was sold around the world, so we used custom three phase autotransformers with taps configured for our existing 480v as well as 380, 400, and 575, all in one transformer. Large contactors were used to select voltages required by the unit under test. I know Hammond Power Solutions lists these in a catalog with common voltages, but they’ll also build you one to your specifications. I liked to use a company in Canada called Marcus Transformer. They’re real easy to work with, have a fast turnaround, and fair prices. If you call them they’ll answer in French, but will switch to English, lol…. Also, Staco Energy Products makes super slick systems like this and will build you an all-in-one package to your specs, and they provide expert advice. We even had one of their 300 KVA three haze variable autotransformers that would deliver anything from 1 to 480v. It was pretty cool. I know this really isn’t helpful to most of the audience, but knowing this stuff exists may come in handy.

[@phillbenitez4216]

Thanks Mike. God bless you all!

[@rickpina5000]

This is gold. The knowledge you give us, no one will ever be able to take away.

[@MikeHoltNEC]

Thank you.

[@lauratanner8475]

Mike Holt is a Dynamo!! Always passionate and right on the mark. Probably no one else has ever had so much working knowledge of the code.

[@MikeHoltNEC]

I love helping you guys, so I guess that is obvious!

[@unsanctionedshortstories5778]

Mike Holt the legend. Sir thank you for all your work and we appreciate it!!!!

[@MikeHoltNEC]

Thank you and you are most welcome.

[@godbledd4theworld791]

Thanks Mike very much needed information

[@Proiectediversediy]

Thanks Mike.Congrats from Romania.

[@MikeHoltNEC]

Wow, thank you and God Bless

[@mahadihasan93]

As always outstanding content. Thank you.

[@MikeHoltNEC]

Glad you enjoyed it

[@murraywendman8222]

Thanks Mike

[@1xtechnologiescablecompany272]

Fantastic job Mike!

[@MikeHoltNEC]

Thank you!

[@brianmcdermott1718]

Great info. As usual. Thanks Mike.

[@MikeHoltNEC]

You are very welcome

[@marcemarce9821]

He said, ook I am been told too fast lol Thank you Mike there is no Mike you're making a big difference for many people, thank you God bless you, I don't have my licence but I am trying.

[@MikeHoltNEC]

I don't know the term 'I'm trying.' This appears to provide lots of excuses to not comit. Please call 352.360.2620 and allow my staff to get you on a program to 'pass' your exam the first time.

[@NameLess-ks4fi]

Mike is the GOAT

[@MikeHoltNEC]

Thanks.

[@poolsdoc9178]

Amazing theory book, every electrician should have it 👌👍👏

[@MikeHoltNEC]

I totaly agree.

[@steven7650]

IIRC you can use whatever color scheme you want as long as you're consistent in the building. So if you make your high leg zebra pink striped, well that's what all of them in that system have to be. I believe there's an exception for repair work and it must be permanently clearly labeled that the colors do not match the rest of the facility.

[@elc2k385]

This video is going in my Favorites.

[@MikeHoltNEC]

I love this topic. It answers so many questions.

[@MrBelal79]

Amazing video as always, also I bought your books, it's amazing.

[@MikeHoltNEC]

Thank you and I'm honored to be part of your success story.

[@Lionofjudah308]

Amen brother

[@bradyy2052]

I watch this to fall asleep hopefully some of the knowledge stays in my head tho fr

[@MikeHoltNEC]

Hopefully...

[@asperbergers7136]

999th like Mike! Thanks for everything you do!

[@MikeHoltNEC]

Aww, thank you for the compliment.

[@robbullock3662]

I love your videos! That does look like a bong on your back shelf though

[@MikeHoltNEC]

I did remove it for that reason.. lol.

[@belindasiason7357]

God bless you mike

[@MikeHoltNEC]

Thank you and the same to you and your family.

[@8yerbrain]

Thank you.

[@MikeHoltNEC]

You're welcome!

[@jolyonwelsh9834]

You are not allowed to use slash rated breakers on an ungrounded or a corner grounded system. I wish they would make all 2 pole breakers straight rated for this reason. It would not cost much more in that they would all be made to the same standard. After all, all three pole breakers are straight rated.

[@arthurcage275]

Can u make a Playlist that is in order of videos to watch to understand theory

[@buckaroundandfindout]

Much love mike.

[@MikeHoltNEC]

Thank you, and the same to all.

[@buckaroundandfindout]

@@MikeHoltNEC wow you really replied. You are awesome and God is great.

[@gilbertraydalida7551]

the best :)

[@85agyoung]

In the video for a Highleg system you show 3 windings on the secondary side. Typically a highleg system would only have 2 windings. This would be the primary purpose for a high-leg or open delta saving money or reducing material. The 2 windings especially on the utility side would be used. The vector of this setup would look like a T. With the node of the T being your neutral connection. The Y axis in the vector would be your high-leg or 208 to neutral voltage.

[@MikeHoltNEC]

A closed or open Delta secondary with a neutral will both give a high-leg voltage of 208V.

[@85agyoung]

Agree with the closed delta giving you the same results. I have never installed or seen a closed delta highleg. Keep up the awesome videos! They have helped me out with getting a better understanding of the NEC.

[@danielgladstone1789]

Hey Mike, great video as always. One question though: Do you use any particular software to draw your diagrams? I like how they have clamp meters etc on lines that you want to display the current reading. Makes the diagram very easy to follow and I'd like to be able to produce diagrams like that for my work as well

[@MikeHoltNEC]

We use CarelDraw.

[@danielgladstone1789]

@@MikeHoltNEC Thank you!

[@jeremymcguire7069]

The pace of this presentation is very fast. That challenges me to follow along and keeps my attention focused. Thank you, you're an excellent instructor.

[@MikeHoltNEC]

Yes it is, but the second and third time you'll notice that I'm going slower...

[@michaeljiron7038]

The question that was asked around the 30 minute mark... Does the SSBJ have to be bonded to the metallic raceway that connects the transformer to the first means of disconnect. Aka ground bushings. Does the answer change if it's flex or EMT?

[@MikeHoltNEC]

Feeder/branch circuit bonding is only required per 250.97 for 277/480V circuits where there is a KO. Nothing else.

[@frederickmartinburg7591]

Hello there Mike, I'm preparing for the master electrician test. Which testing material would you recommend? God bless

[@MikeHoltNEC]

Call 352.360.2620, and follow the recommendations given. Ask for a MH discount.

[@frederickmartinburg7591]

@@MikeHoltNEC amazing

[@brianharmeson3144]

I have a question concerning high leg identification. You stay in this video and in your diagram that the high leg must be orange. However, the code states the high leg can be identified by an orange outer covering "or another effective means". So, my question is, is the high leg actually required to be orange If you use another effective means to identify it? Thank you.

[@MikeHoltNEC]

I can't find where I made that statement. The identification of the high-leg conductor must be in accordance with 110.15.

[@tvblood3550]

So in a single phase system, one only wire makes the main circuit and then comes the neutral and earthing,it's like a game in wich to got shocked I just have to close a circle=circuit I get that it's all pretty clear in the figures you show, actually thanks to your drawings I can understand now the whole thing. But now, where does the big circuit ends? Because being a big circle means L1 must meet L2 in some point right? According to your first lesson( current always come back to the source), L1.should come back to the source using to paths (neutral wire or L2 wire) so where does L1 becomes L2? Is this meeting point a phisical place like a substation or something?

[@MikeHoltNEC]

Watch kzbin.info/www/bejne/o6HKcol7abqqfNk

[@ohmware2020]

hi make, please make a video about single phase 2 wire system, line to ground/neutral system

[@MikeHoltNEC]

I'm confused, 2-wire is just that, 120V L-N

[@dwaynes965]

I use 208 single phase all the time. 2 hot leads and a ground. no neutral.

[@undaya]

The conduit is the ssbj

[@tfun101]

Mike people keep telling me I’m wrong..I just want to make sure. If I have a 480 primary and 208/120 secondary transformer, or any other kind of transformer for that matter..Let’s say the neutral on my secondary is bonded correctly with a SBJ and I have an effective ground fault current path, and everything is correct. EXCEPT I don’t ground my transformer to the dirt, or building steel, or a water pipe or anything else. I still clear faults and still have correct voltages right? People are telling me it’s a floating neutral and my voltages are all going to be off and I’m not clearing faults, etc.

[@MikeHoltNEC]

Yes, you are 100% correct. The secondary bonding established the zero reference and effective ground fault current path. Of course you knew that.

[@kahlil4745]

The ruler thing is silly. It's a sine wave and that measurement is related to the area under the curve.

[@ecospider5]

At the 3 minute mark your slide is Transformer Turns Ratio. The bubble at the top says 240v. Shouldn’t that be 120v. So 24v per turn x 5 = 120v.

[@MikeHoltNEC]

Yep, sorry for the typo in the graphic.

[@soloado5084]

Sir, I want you to clear this confusion in my mind raised after listening to your talks on grounding . Please , I know dis video is off it . Can one say that grounding/earthing only takes care of events created by lightening ?

[@MikeHoltNEC]

Watch MikeHolt.com/Fundamentals and you'll understand what I'm saying.

[@rigobertoruiz6136]

Which videos are the first two we need to watch?

[@MikeHoltNEC]

This is the summary, so only this one.

[@shellypizzo6664]

Yes he mentions 2 previous videos that should be watched before this if he is going to fast. What are they?

[@MikeHoltNEC]

@@shellypizzo6664 This was a series of 'live' video recordings. Only some of these are kept on KZbin. Sorry.

[@Jecoopster]

Who has the links to the first two videos?

[@MikeHoltNEC]

There were all combined into this summary video.

[@agussurachman5246]

<a href="#" class="seekto" data-time="198">3:18</a> in left slide, 480V/20 should become 24V instead of 48V, shouldn't it?

[@MikeHoltNEC]

Yea.... crap... thanks. Sorry for the typo.

[@makecashnow6714]

Hi mike

[@flinfaraday1821]

<a href="#" class="seekto" data-time="225">3:45</a> The top labels in this graphic make no sense to me. 480V/20 turns = 48V per turn?? 24V x 5 turns = 240V?? How?

[@makecashnow6714]

I am Michael holt too a master Electrician people mistake me for you but I am not in Florida lol

[@MikeHoltNEC]

I’m not sure if that is good or bad. God Bless you brother.

[@BossManGlizzy]

I need to card out any tips to begin studying so i can pass for the first time? I have not began studying

[@JohnQPublic345]

Star reading through the NEC page by page

[@BossManGlizzy]

Bill Lumburgh will that actually help

[@JohnQPublic345]

I'm old school. When we wanted to learn, we worked for low wage or free....and at same time hit the books hard. Today, everyone thinks they can do anything by watching a handful of youtube videos

[@MikeHoltNEC]

Call my office 352.360.2620 and get the proper training program.

[@nlee5034]

Ugh!! They (powers that be) REALLY need to think about what words to use, before using them… Trying to explain “Grounded v Grounding”, and then an “ungrounded system”, makes me give a “parent-like” answer, to their question: “How is an ungrounded system, one with no ground… when the Grounded wire, is the neutral?” Mr- “IDK… it’s just how it is. “

[@mikewendell4748]

Thanks Mike