200.3 What does this mean?

[Twoskinsoneman]

I was wondering if this might by a typo because I was reading an exam prep question that was drawn right from this article (as indicated by "200.3" notation next to the question).
The question is True or False
"Premises wiring shall not be electrically connected to a supply system unless the supply system contains, for any grounded conductor of the interior system, a corresponding conductor that is ungrounded."

The code says this

200.3 Connection to Grounded System. Premises wiring
shall not be electrically connected to a supply system unless
the latter contains, for any grounded conductor of the interior
system, a corresponding conductor that is grounded. For the
purpose of this section, electrically connected shall mean connected
so as to be capable of carrying current, as distinguished
from connection through electromagnetic induction.

So what does it mean?
Any grounded conductor of the interior system requires a corresponding grounded conductor?

 

[don_resqcapt19]

It means that if you have equipment that requires a grounded conductor, then the supply to that building must have a grounded conductor. It also means that if supply is not grounded and the equipment does not need one, then the supply to the building does not need a grounded conductor. If the supply is grounded and the equipment does not need a grounded conductor, 250.24 requires that the supply grounded conductor be run to the service disconnect.

 

[Smart $]

It means that if you have equipment that requires a grounded conductor, then the supply to that building must have a grounded conductor. It also means that if supply is not grounded and the equipment does not need one, then the supply to the building does not need a grounded conductor. If the supply is grounded and the equipment does not need a grounded conductor, 250.24 requires that the supply grounded conductor be run to the service disconnect.

I don't believe that is quite correct... but it is close. What I see as the difference is 200.3 is regarding the system the equipment is connected to, and not necessarily the service. For instance, you could have an ungrounded 480V system supplying the building/premises. You have 120V equipment which requires a grounded conductor. A transformer is used to create an SDS that the secondary's system is grounded and serves the 120V equipment. The requirement is met even though the service is ungrounded.

 

[jumper]

Thanks Jack, my head hurts after reading that section.

 

[don_resqcapt19]

Smart,
You are correct. The rule applies to the souce of supply for the circuit that serves the equipment and that would not have to be the utility.

 

[Twoskinsoneman]

Thanks for the comments don and smart (sorry about the headache jumper )
I guess it's a pretty simple concept after understanding what they were saying. I think they muddied it up a bit, especially with the part about interior system....