Calculating Voltage Drop

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Calculating Voltage Drop

Рет қаралды 59,159

Күн бұрын

#AccessToPower #AccessElectric
accesstopower.com
In this episode of AccessToPower we will discuss how to calculate voltage drop in a circuit using the Tables in Chapter 9 of the National Electrical Code (NEC). We go over how to use Table 8 to calculate the "K" or the constant value of copper and aluminum. We show you how to use the "K" Value to calculate the voltage drop of a circuit using nothing but Table 8 in the NEC. We then look at my preferred method which uses Table 9 in Chapter 9 of the NEC to calculate voltage drop using the "Z" or Impedance values of Copper and Aluminum conductors given for each size in various kinds of Conduit.

Пікірлер: 60

@Jayson8181 4 жыл бұрын

There is so much garbage out there, I'm really happy to find someone who is clear, easy to understand and stays focused on the question at hand. Thanks and keep on doing what you're doing!

@KevinCoop1 4 жыл бұрын

As a designer for a contractor and doing thousands of calculations over the years, I always wanted to know the wire size needed in one calculation. I did not want to keep guessing until I got less than 3%. Less complicated method. 2xKxampsxLdivided by 3% of voltage= cm. Conductor properties table will give you needed wire size. Also, for balanced 3 phase 3 wire multiply single phase calculation at end by .86. 1.73/2=.865. And for balanced three phase 4 wire, multiply single phase calc at end times .5. If balanced load, then no neutral current. 1/2=.5. Respectfully submitted, Kevin

@12mandingos 5 жыл бұрын

Thank you for putting these videos together! For someone getting underway in the trade I find these videos very helpful. Shout out to the 209 too!

@jeremiahwoodhull6122 Жыл бұрын

Thank you for your time in making this video. It is easy to follow along and understand. Especially on impedance. Once again thank you.

@AccessToPower Жыл бұрын

Thanks for commenting. I appreciate the feedback.

@energyexecs Жыл бұрын

...Nice learning video. I also like using Z (the impedance) because it provides a glimpse for the human that impedance plays an important role in voltage delivery to the end point.

@ethanbrewer14 4 жыл бұрын

Thank you for this video! It helped me a lot in understanding and feeling confident in my calculations.

@bcv3934 5 жыл бұрын

Another good informational video👍 Your doing such a good job for those who want to learn more and improve.

@frankvieira764 Жыл бұрын

I think you're Portuguese, but I love you're videos. Thank You.

@georgegenteroni6645 2 жыл бұрын

Thank you for the clear discussion abou voltage drop.

@davidjackson4112 11 ай бұрын

Thanks for your help in solving voltage drop calculation.

@victorvasquez5418 Ай бұрын

Good job thank you for your help

@azscib 4 жыл бұрын

That was such a WELL done video. So clear and precise! great job. Others should follow as some ramble through their videos. Again ~ thank you!!!!

@AccessToPower 4 жыл бұрын

Rich Scibetta thanks for the great comment!

@ernestocortez2957 4 жыл бұрын

Thank you! Im getting ready to take my state test here in CA this Saturday. I'm ready for a voltage drop question.

@AccessToPower 4 жыл бұрын

Ernesto Cortez, thanks for the comment. Good luck on your test.

@elc2k385 3 жыл бұрын

Awesome! Thank you once again.

@Buhzuka 4 жыл бұрын

Super Helpful! Good Informational video!!

@bojitti 4 жыл бұрын

Thanks a lot. I find this very useful.

@tedecacao Жыл бұрын

Thank you so much for this video! Subscribing now

@AccessToPower Жыл бұрын

Thanks! Glad the video was helpful!

@yasirjohny 5 жыл бұрын

Thanks A lot , your method of teach is very unique I completely understand of VD calculations. 🌹🌹🌹

@crisrobersonsantos9192 3 жыл бұрын

Thank you very much for the very clear, detailed and straight forward video lesson. This helps me a lot on my studies. NEC Table 9 have a title of: Alternating-Current Resistance and Reactance for 600-Volt Cables, "3-Phase", 60 Hz, 75C (167F) - Three Single Conductors in Conduit May I kindly consult if we can use NEC Table 9 for 1-Phase circuits? even though the title indicates "3-Phase" Thanks again and more power to your channel.

@peterponcedeleon3368 4 жыл бұрын

Thanks!! Keep them coming.

@ankitpanchal5766 2 жыл бұрын

Great video. But can we use Vd = 2*L*R*I / 1000 formula?

@rickydags 2 жыл бұрын

Thank you for this video. Question for you about the impedance for the single phase case. The Chapter 9 Table 9 of the NEC says in the title that it is for three phase power, but you used it in the single phase case. Is there something in the NEC that indicated that table 9 can be used on the single phase case or is there another table for the single phase case?

@aimansado3457 4 жыл бұрын

where can I get the formula book? internet?

@bryanbecker 8 ай бұрын

When would one use the “coated” section?

@pululunguente 4 ай бұрын

And what about you having 2 sets of conductors with Z method? Please Help!!

@washingtonmazzini9120 11 ай бұрын

GOOD AFTERNOON, I HAVE THE FOLLOWING QUESTION: IF A THREE-PHASE FEEDER IS INSTALLED IN A METAL WIREWAYS, TABLE 9 IS APPLIED TO CALCULATE THE VOLTAGE DROP?

@reyniernunezbeltran2730 Жыл бұрын

Both methods should give equivalent results. The reason why using table 9 gives you a slightly different result is because eddys current (Q) losses is not taken into account. But if (Q) is used both methods should be 99.9 % equivalent.

@amadogomez436 4 жыл бұрын

Great

@rowellcanillo7469 3 ай бұрын

Is table 8 is only applicable in DC system?

@josemarti8642 3 жыл бұрын

How do you factor in multiple runs of conductors into that Voltage Drop equation?

@rupe53 3 жыл бұрын

Jose ... you need to figure the drop for each run separate then add up the results for the whole run. If the numbers are too high (percentage of drop) then you need larger wire. You will almost never have a problem if you stick to 80% loading of a branch circuit and stay under 100 ft in a run. To ease the brain work use one of the voltage drop calculators on the web. You plug in wire size, load, and run length. They will tell you voltage drop and percentage. After you use it a few times you will get a feel for where you need to be.

@bluesolarmx 3 жыл бұрын

If using meters, for example with a 10AWG cable, would it be the same? 4.070*10380/1000m?

@omargarcia4401 3 жыл бұрын

Great video only issue with using the table 9 formula with impedance (z value) is that the impedance of Table 9 is only good for 3phase - Three single conductors in conduit as per the title of that Table so I’d assume it’s not totally accurate for use with Single Phase Voltage drop calculations. Sorry to be that guy.

@christopherestevez6375 4 жыл бұрын

Only thing is i couldnt find where to find chapter 9 table 8 in my nec book

@Rabb_L_Rouser 11 ай бұрын

Why does no one bring up how to find voltage drop of wire larger than 4/0? I need voltage drop of 850ft run of single conductor aluminum 750kcmil, 3000A.

@562sela8 3 жыл бұрын

nice vedios

@matthewgaskey4954 3 жыл бұрын

good video! a couple questions tho. How did you get 2.75% from 13.20 in the single phase method (15:27) and your applied voltage cell reads 480. thanks

@AccessToPower 3 жыл бұрын

Matthew Gaskey also, this calculator may be helpful. www.calculatorsoup.com/calculators/algebra/percent-difference-calculator.php

@josericardomarin6911 4 жыл бұрын

Hola boss this Is José Marín can you please maje a vídeo for load calculacions for motors. Thanks

@AccessToPower 4 жыл бұрын

hey Jose. hope all is going well with you... I will try and do a video on that subject.

@mikechan-nel8390 4 жыл бұрын

@@AccessToPower sir what is the formula to get the percent?

@hoovie3000 3 жыл бұрын

Why can't we use Chapter 9, Table 9 of the NEC?

@johnnytotheworld4802 4 жыл бұрын

Which cable is affected by the voltage drop?

@omargarcia4401 3 жыл бұрын

All cable

@oscar27ization 4 жыл бұрын

You said single phase formula but the voltage drop was 480??? Wasn’t suppose to be 120v

@teardowniscool 3 жыл бұрын

Good point !

@Studi314 4 жыл бұрын

Is the second formula 2xZxDx(I /1000) the way you have it written or is it really ( 2xZxDxI)/1000?

@AccessToPower 4 жыл бұрын

Studi314, I’m not sure what you’re referring to because I have a written (2xZxDxI)/1000.

@Studi314 4 жыл бұрын

At the time 13:00, the formulas do not have any parenthesis in them.

@AccessToPower 4 жыл бұрын

Studi314 , I see what you’re saying. It would’ve been helpful to have the formulas with parentheses. But also under the rules of orders of operation in math, multiplication always comes before division. So the formula is correct with the parentheses or not but it is more helpful with the parentheses

@veritasaequitas9875 4 жыл бұрын

CM in the equation. What are Circular Mills?

@veritasaequitas9875 4 жыл бұрын

It's ok. Got it. Just wondering what's wrong with square mils. Or even square inches.

@AccessToPower 4 жыл бұрын

circular mills is the circular cross section of the wire we are examining. You can find the CM for each size of wire in Chapt 9, Table 8 of the NEC. Check minute mark 12:38 and you will see that table.