Grounding

[erickench]

Hi Guys, okay I came across a very interesting multiple choice question in my passbook about grounding. Here it is:

With regard to the grounding of electrical systems, it is CORRECT to state that electrical systems

A. must always be grounded
B. must be provided with a ground detector, if ungrounded
C. must always have a separate grounding conductor
D. of less than fifty volts need not be grounded

I would have thought 'B' would be the answer because the definition of 'Grounding Conductor" in article 100 is: A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes. An ungrounded system has an electrode and the definition say's nothing about connecting a grounding conductor to the service neutral. What do you guys think?

 

[Dennis Alwon]

Without looking I believe it is "D" . I seem to remember reading that.

 

[Dennis Alwon]

Without looking I believe it is "D" . I seem to remember reading that.

I found art. 250.20(A) but that requires some systems less then 50 volts that do need grounding. I guess the general rule is they don't need grounding.

 

[augie47]

without a voltage mentioned, I'm stuck with "none of the above" so I must be overlooking something.

 

[Dennis Alwon]

without a voltage mentioned, I'm stuck with "none of the above" so I must be overlooking something.

D does mention 50 Volts but it is not a good question or a good answer.

 

[erickench]

D does mention 50 Volts but it is not a good question or a good answer.

Yes the answer key does say 'D' but under certain conditions these systems are required to be grounded. Your right though. It's not a good question or a good answer. Very tricky.

 

[erickench]

Excuse me did I say 'B'? I meant to say 'C' must always have a separate grounding conductor. My apologies.

 

[Dennis Alwon]

The use of the term grounding has changed because of this issue. A separate grounding system can be many things. I assume they mean an EGC but an ungrounded system does not use an egc....Oh well.

 

[augie47]

Preparing question can be a difficult task.
It seems simple until you take into account all the possible variables, exceptions, etc.

 

[erickench]

The use of the term grounding has changed because of this issue. A separate grounding system can be many things. I assume they mean an EGC but an ungrounded system does not use an egc....Oh well.

I think you would have to look at the present definition of 'Grounding Conductor'. All it say's is that the system is connected to the grounding electrode through this grounding conductor. I would assume that all non-current carrying metal parts of an ungrounded system would have to be bonded together and then connected to a grounding electrode.

 

[K8MHZ]

Preparing question can be a difficult task.
It seems simple until you take into account all the possible variables, exceptions, etc.

If a person is not able to do as you say, they are not fit to author test questions.

 

[LarryFine]

If a person is not able to do as you say, they are not fit to author test questions.

That certainly applies to my son. :roll:

 

[roger]

If a person is not able to do as you say, they are not fit to author test questions.

So in your opinion, an author that has penned say 10,000 questions that the answers can not be disputed is not fit if he/she had one question that might possibly be incorrect.

Boy, that puts a lot of pressure on an electrician that has done 10,000 service calls without a mistake then all of a sudden..........., I shutter to think of the sense of failure and the humility when the realization of the unfitness becomes apparent to this electrician.


Roger

 

[cadpoint]

Just reading it as a layman (if I may) my thoughts were they are all right!

No one's going to support "A", all the other's have been called out!

One can only say "yes" something's going to happen due to the type of circuit or service to be addressed with active Code participation.

I was reading for multiply choices...