ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
A 5-20(20a) receptacle is legal on a 15a circuit?
by libellis - 10/10/21 12:46 PM
GFCI's pops in large numbers
by dsk - 10/07/21 03:46 PM
Backup Generator Done Right
by timmp - 10/06/21 02:07 PM
How's all our Non-US folks doing?
by dsk - 09/30/21 05:06 AM
Well I am back to stay (nearly 6 years)
by Bill Addiss - 09/26/21 11:09 PM
New in the Gallery:
240/208 to a house
240/208 to a house
by wa2ise, October 9
Now you know.
Now you know.
by Tom_Horne, September 7
Who's Online Now
1 members (Scott35), 8 guests, and 22 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Sep 2019
Posts: 21
Likes: 1
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
Joined: Oct 2000
Posts: 4,042
Likes: 3
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
Joined: Sep 2019
Posts: 21
Likes: 1
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.
Joined: Oct 2000
Posts: 4,042
Likes: 3
Member
Glad to help Phil,

smile


Bill
Joined: Sep 2019
Posts: 21
Likes: 1
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.
Joined: Oct 2000
Posts: 4,042
Likes: 3
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
Joined: Sep 2019
Posts: 21
Likes: 1
Member
Thanks.

Confusing wording in this code section.

Phil


Where ever you go, there you are.

Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
togol
togol
NW In. USA
Posts: 421
Joined: September 2005
Top Posters(30 Days)
dsk 5
wa2ise 1
Popular Topics(Views)
284,589 Are you busy
217,288 Re: Forum
203,646 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5