17:40 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.
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.
For those confused the illustration @ 3:00 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
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.
What concerns me Mike when You're gone who's going to take over. Somebody has to come forth and stand and take your place. Without these programs the industry suffers. I couldn't imagine not having these programs Sean Denver Colorado
Sean, when I'm gone MHE will still be there with great leadership and technical skills. But these Mike Holt Video posts will not be replaced... so I hope others value what I'm sharing and show gratitude and not give me any crap.
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.
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.
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.
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.
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.
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.
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.
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.
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
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?
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.
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 ?
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?
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
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. “
