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NEC Question_Cord-&-Plug EGC shorter then Neutral #220238 09/04/19 09:38 AM
Joined: Sep 2019
Posts: 19
pcsailor Offline OP
Member
Hi all,
I'm new here, first post.
I'm taking my Minnesota Master exam this month and wanted a resource to ask some questions that are causing me hair loss <:

I'm having trouble with this question, any direction would be appreciated.

"Equipment grounding on a cord and plug connection has to be shorter then the neutral pin for safety."
True or False

Seems simple enough but I can not find a code reference to this answer.
Here's where I have looked (NEC2017):
250.114
250.124(A)
250.130(A)
250.138
590.4(D)(1)
590.6(B)(3)
406.4(C)
Internet research:
250.24(C)
Article 200
210.4(B)
300.13(B)

I'm thinking the answer is False as the over current protection device determines the disconnection and therefore safety, but I'm uncertain how to prove this using the code.

Thanks all,
Phil


Where ever you go, there you are.
2017 / 2014 NEC & Related Books and Study Guides
Re: NEC Question_Cord-&-Plug EGC shorter then Neutral [Re: pcsailor] #220239 09/04/19 09:58 AM
Joined: Oct 2000
Posts: 3,929
Bill Addiss Offline
Member
Welcome pcsailor!

False,
check 250.124(A)

Has to be longer for first -make last-break connections

Bill

Last edited by Bill Addiss; 09/04/19 10:00 AM. Reason: added last part

Bill
Re: NEC Question_Cord-&-Plug EGC shorter then Neutral [Re: pcsailor] #220241 09/04/19 10:05 AM
Joined: Sep 2019
Posts: 19
pcsailor Offline OP
Member
Wow, tough one for me.
I read that to but didn't get my head around it.
Thanks Bill 😁
Phil


Where ever you go, there you are.
Re: NEC Question_Cord-&-Plug EGC shorter then Neutral [Re: pcsailor] #220242 09/04/19 10:58 AM
Joined: Oct 2000
Posts: 3,929
Bill Addiss Offline
Member
Glad to help Phil,

smile


Bill
Re: NEC Question_Cord-&-Plug EGC shorter then Neutral [Re: pcsailor] #220266 09/15/19 12:09 AM
Joined: Sep 2019
Posts: 19
pcsailor Offline OP
Member
Hi,
I want to dive a bit deeper into 250.124(A) (NEC2017)
Here is the actual code:
"(A)
Separable Connections. Separable connections such as those provided in drawout equipment or attachment plugs and mating connectors and receptacles shall provide for first-make, last-break of the equipment grounding conductor.
First-make, last-break shall not be required where interlocked equipment, plugs, receptacles, and connectors preclude energization without grounding continuity.
"

Here's the question, and answer, from my course practice test:
"Equipment grounding on a cord and plug connection has to be shorter than the neutral pin for safety."
Answer: "No  250.124.A"

Am I correct in understanding the code language that this answer of 'No' (or False) is specifically referring to the second sentence of 250.124(A)?
If so, how do 'cord and plug connections' 'preclude energization without grounding continuity'?
I mean, we could be talking about simple extension cords here, yes? You can cut off the ground terminal and the two ungrounded conductors still have an electrical path when plugged in.

What am I missing?

Thanks,
Phil


Where ever you go, there you are.
Re: NEC Question_Cord-&-Plug EGC shorter then Neutral [Re: pcsailor] #220272 09/15/19 03:19 PM
Joined: Oct 2000
Posts: 3,929
Bill Addiss Offline
Member
Phil,
Quote
"Equipment grounding on a cord and plug connection has to be shorter then the neutral pin for safety."
True or False


Here's my take on it: False

Refers to:
Code
Separable connections such as those provided in drawout equipment or attachment plugs and mating connectors and receptacles shall provide for first-make, last-break of the equipment grounding conductor.

To do that the Grounding Pin is longer.

Code
First-make, last-break shall not be required where interlocked equipment, plugs, receptacles, and connectors preclude energization without grounding continuity.

This part is just saying it doesn't have to be longer, doesn't say it must be shorter than Neutral or nonexistent. So, still False


Bill
Re: NEC Question_Cord-&-Plug EGC shorter then Neutral [Re: pcsailor] #220275 09/16/19 05:26 AM
Joined: Sep 2019
Posts: 19
pcsailor Offline OP
Member
Thanks.

Confusing wording in this code section.

Phil


Where ever you go, there you are.

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