200.3

[bennie]

Is this interpretation correct?

200.3 Connection to Grounded System.

Paraphrased;

An ungrounded supply system (utility distribution) shall not be solidly electrically connected to a grounded premises wiring system.

Magnetic coupling by a transformer is not considered a solid electrical connection.

 

[roger]

Re: 200.3

Bennie, the kicker here is, (I have heard) that some in the CMP capacity do not consider an EGC or a GEC to be a direct eletrical connection.

Roger

 

[bennie]

Re: 200.3

Correct Roger, these same individuals are the authors of the Soares Grounding Book.

The green wire no longer carries current

 

[bennie]

Re: 200.3

If my first statement is correct then...

A grounded supply system must be electrically connected to the premises wiring system.

Electrically connected means "capable of carrying current".

The new technology adopted, and published, is violating all the scientific laws of physics.

 

[roger]

Re: 200.3

Bennie, isn't it funny that the term Premisis Wiring is a large part of the reason for the code, and article 250 is the largest single article in the code, yet when it comes to the two articles coming together, article 200.3 seems to say 250 doesn't apply. :roll:

Roger

 

[don_resqcapt19]

Re: 200.3

Bennie,

An ungrounded supply system (utility distribution) shall not be solidly electrically connected to a grounded premises wiring system.

If the utility supply to the premises is an ungrounded system, how could you possibly have a grounded system within the premises that is directly supplied by the utility???
Don

 

[don_resqcapt19]

Re: 200.3

Roger,

... yet when it comes to the two articles coming together, article 200.3 seems to say 250 doesn't apply.

I don't understand this statement. Can you expand on it?
Don

 

[ronaldrc]

Re: 200.3

Hello Bennie hope you have made a full recovery.

But on this subject maybe I'm reading it wrong, but doesn't the 2nd paragraph of 200-3 when it say as distinguished from the connection through electromagnetic induction mean that it doesn't refer to the induction coupling as a direct connection?

Or am I reading it backwards?

Ronald

 

[bennie]

Re: 200.3

Hello Ronald: You are correct, magnetic coupling is not a direct electrical connection. A direct electrical connection is a conductor capable of carrying current.

I will not be recovering. I have 15% of one lung working and 49% of the other. I am 73 years old, four more years will give me the expected life span

 

[ronaldrc]

Re: 200.3

Bennie don't give up doctors as much knowledge as they have are proven wrong every day.

A good positive attitude does more than anything.
Our prayers are with you.

My point about 200-3 was they are pointing out that they don't consider the magnetic coupling a direct electrical contact.

You,myself and the board understand that it is not a direct electrical connection, but on the same token that doesn't mean that there are no contradictions on grounding, when you tie the grounds of the primary and secondary of a unility feed to the ground of a customers service together and then call the customers service separately derived thats a contradiction.

Separately derived implies separated and as long as there is a conductor tieing it all together it is not separated.

Ronald

 

[bphgravity]

Re: 200.3

I really don't understand what the arguement is here? Obviously, you have to have premise wiring that consists of a grounded conductor. If the utility that is present does not have a grounded conductor, the code says the premises cannot be connected to it. This does not include the possibilty of a SDS. Am I not understanding the point of the question? What do you mean violating the laws of physics?

 

[bennie]

Re: 200.3

bph: Sorry, this thread is fragmented due to previous discussions. It will be hard to follow unless one was in at the beginning.

My only point is that some sections in the code are addressing systems that no longer exist. This section, in question, dates back to the 20s and 30s.

Utility companies do not supply an ungrounded system to premises wiring.

Some individuals fabricate an explanation to match the text.

 

[ronaldrc]

Re: 200.3

Can't agree more that would make a hell of a mess if you tied your house ground to a ungrounded high voltage line that wasn't at ground potential

 

[ronaldrc]

Re: 200.3

Bennie my defrager doesn't even work on my computer do you reckon it will work on this?

 

[bennie]

Re: 200.3

1940 NEC, Section 2523. Alternating-current Systems with Exterior Connections.

Interior wiring systems supplied by a grounded secondary alternating-current distribution system shall be grounded at each individual service.

There is no transformer supplied separately derived system in modern wiring methods.

The only separately derived system is with a generator that does not have a ground wire connected to the utility MGN.

 

[Ed MacLaren]

Re: 200.3

Separately derived implies separated and as long as there is a conductor tieing it all together it is not separated.

That is not at all what is meant by the code term "Separately Derived System". The key word in the term is derived

Derived from means "supplied from" or "to originate from".

The code term "Separately Derived System" means a system that is supplied from a source (transformer or generator) other than the one that the service is supplied from. That's all it means.

It's not like the code makers devised the term first, and then designed a "system" to fit it.

These systems, supplied from on-site transformers or generators existed, and the code makers needed a name for them.
They just happened to choose the term "Separately Derived System" to describe such a system.

System 3 in the sketch below is supplied from a different transformer than the one that the service is supplied from.

Ed

[ March 23, 2003, 11:38 PM: Message edited by: Ed MacLaren ]

 

[bennie]

Re: 200.3

I am sorry Ed, there is no written documents that substantiate your understanding.

There has never been any code panel action on this topic. All changes have been by technical staff.

The definition of "Separately Derived System" is clear. The transformer is the source of power for a separately derived system, it is not the system.

 

[bennie]

Re: 200.3

Calling a transformer a separately derived system is like calling a duck, a canary.

 

[iwire]

Re: 200.3

Looking at Ed's drawings, I think it is clear the SDS starts at the secondary windings of the transformer.

That said, XO, X1, X2 and X3 are a SDS, splitting hairs here for sure.

Bennie, my Dad had similar health issues and more then doubled what the Doctors told him.

Best of wishes to you, and don't let a bad day get you down.

Sincerely, Bob

 

[bennie]

Re: 200.3

Thanks for the encouragement Bob.

I agree that the secondary is part of the separately derived system, if not solidly connected to another system.

A transformer will be electrically connected to supply conductors originating in another system when the X-0 is solidly connected with the equipment ground conductor.