100 Days of Article 100: Separately Derived System

The definition of "separately derived system" is covered here.
For an in-depth discussion on how transformers work, go here: • Transformer basics--th...
For the various configurations of transformers covered in the NEC, go here: • Transformer configurat...

[@waylander2]

You are the premier source for NEC instruction. You explain the subject matter clearly so it's easy to understand. Thanks for your work.

[@jasonparkinson7621]

You made it easy to understand. You're a good teacher. Muchas gracias! 👍👏

[@jaaqess2525]

I’m a helper and we’re working on a building that doesn’t have a neutral on a 480 that is feeding a transformer that steps it down to 120/240. This makes it make so much more sense why we bond that transformer. I forgot they are inductive just like the pots on poles.

[@Werdna12345]

Electric Pro Academy sent me here. Looking forward to learning more from your channel!

[@Nahum17good]

This is excellent information. Thank you for your great interpretation!

[@3MEN2]

Ryan you are my electrical guru.Thanks for sharing the knowledge.Matter of fact i think you are brilliant.Right on Ryan.

[@legendaryl2316]

I've watch all your videos sir and it it helps me a lot to understand the book. I'll be taking master electrician here in the Philippines. Thanks for this spoon feeding videos. 😊

[@BuzzElectricLlc]

Great , straight forward and to the point

[@BuchananCounty]

Thank you, Sir, for sharing your knowledge and experience !!

[@n.r.6833]

Great video! Cleared that right up for me!!

[@MrMaxyield]

Best in the business...!
Thanks Ryan...!! 🎩🧙‍♂️⚡

[@tonyhddodge4282]

Great job Ryan and thanks. These videos help me out greatly. Does a separately derived system need to establish its own earth ground system or can it tie in to the existing.

[@alejandrovelasco9573]

Thank you for sharing your knowledge to us keep it up.

[@farkmuckerzerg634]

Excellent video

[@--JohnDoe]

Thank you very much.

[@torosalariasalaria9849]

Thank you for making it easy !
Since the ATS is the first disconnect when the neutral is not switched because it is not being separately derived system, does the neutral and ground need to be separated at the generator and not being bonded ?

[@realvanman1]

The topic of transfer switches has been much discussed on a forum that I frequent called Smokstak. The question is, in the case of a transfer switch that does not switch the neutral, what do you do about the requirement that the system bond be located at the first point of disconnect. In such a system the bond is remote from the generator and it's breaker, which is the first point of disconnect when running on generator power. This has always been the contention in the discussion. But I believe I have answered my own question! Since the generator is Not considered a Separately Derived Source in the case of a transfer switch that does not switch the neutral, the first point of disconnect rule does not apply. Is this correct?? This answer may clear up years of discussion lol!

[@RyanJacksonElectrical]

Correct, if it is not a separately derived system you are not permitted to make that connection. A transfer switch with a solid neutral means you do NOT have a separately derived system.

[@garza1367]

So let’s assume in a commercial building we have Utilty power coming in via xfrm then hits a switchgear, then feeder panels and then branch circuit panels. At which point (panel) do we bond the grounds and neutrals ???

[@V21IC]

Mmmm.....! What about a UPS(online, offline, bypass)? In the absence of a mains supply, It can generate a line voltage from its batteries. It has a transformer.

[@Godfirst9845]

I’ve had this argument with inspectors and coworkers. It sometimes takes many reads of the code book for us to be on the same page…

[@o0DJANIMATE0o]

This is Gold

[@AlfredoSuarez-rl3qf]

THANKS !!!

[@ChrispyTofoo]

Is reverse wiring a standard xrm to achieve a step up output an acceptable practice.. ie: 208v to 480v

[@roberttempest9576]

You're my hero

[@Superman-ed9rs]

Thank you

[@cyrillejiokeng2994]

Very nice explanation, I really liked it.
I would like you to help me to use the code box I really have the gaps. Thank you

[@Ormaaj]

Great!

[@Sparky-ww5re]

Awesome. So just to clarify, let's say, we have a very large apartment complex, and has two different services, a 1200 amp 120/208Y 3ø disconnect on the west end, and another 1200 amp 120/208Y 3ø disconnect on the east end, this would count as a separately derived system? I've seen this setup in Charlotte NC on some of the larger complexs that were like 20 stories or so and kinda wondered how they would classify something this massive.

[@RyanJacksonElectrical]

No. A service can never be a separately derived system, by definition.

[@josegomez6549]

They're both services, they're also tied by the utility, so they're both not separately derived systems

[@gcg9056]

would a 35' pole light for parking in a commercial area need its own ground rod?

[@RyanJacksonElectrical]

No.

[@Dee-xj4tg]

Ryan Jackson rules🤘

[@elc2k385]

Sweet

[@troymilleraz]

Thanks for the video. You may want to invest in a better mic though... You sound distant.

[@realestateservicessaleshea99]

🍿🥃🙂👍🏻

[@tarachandmyer4262]

*"IN. MY. OPINION. THIS. GLITCH. IS. WHAT. EVERYONE. USES. AM. I. RIGHT?"*
*"**B.ETHY.BAR**"*
*"WHAT. IS. THIS. SONG. USED. IN. THE. VIDEO?"*
*CERTIFICATED*