ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Violation?
by renosteinke - 01/27/23 09:52 PM
Does NEC 551.71 (F) apply to dwellings?
by BigB - 01/20/23 10:46 AM
Power submeter connections
by HotLine1 - 01/19/23 09:09 AM
AFDD's coming to the UK
by Texas_Ranger - 01/17/23 07:22 PM
New in the Gallery:
Burger King crown sillyness
Burger King crown sillyness
by wa2ise, December 11
240/208 to a house
240/208 to a house
by wa2ise, October 9
Who's Online Now
0 members (), 26 guests, and 13 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#80156 03/06/02 04:17 PM
Joined: Jul 2001
Posts: 29
T
tmon Offline OP
Member
Does anyone have any information concerning adding onto a motor control center by connecting cables to the horizontal main bus? A breaker would be installed at the end of the MCC and it would be within 10'. I am actually hoping to find arguments against doing it. Thanks

Stay up to Code with the Latest NEC:


2020 NEC & Related Reference & Study Guides
2020 NEC & Related Reference & Study Guides
Pass Your Exam the FIRST TIME with these Exam Prep Combos:
 

>> Master Electrician Exam Prep     >> JourneyMan Electrician Exam Prep
 

#80157 03/06/02 05:43 PM
Joined: Oct 2000
Posts: 2,749
Member
I would begin by reading the 2002 NEC Part VIII. Motor Control Centers in Article 430.
tmon:

I can think of a few items that would lead me to believe that what you propose may be in violation of the rules in some parts of this place in the code, and in addition, 90.7 and maybe even 110.2 to give a few references for others to think about when responding to your question.


Joe Tedesco, NEC Consultant
#80158 03/06/02 06:32 PM
Joined: Nov 2000
Posts: 2,148
R
Member
Does the cable ampacity equal or exceed that of the main bus? Are there provisions to terminate cables in the MCC or you making some makeshift connection?
Don(resqcapt19)


Don(resqcapt19)
#80159 03/06/02 07:02 PM
Joined: Jul 2001
Posts: 29
T
tmon Offline OP
Member
The cable would not be equal to the bus amperage. I could not find anything in the NEC stating that the tap conductors be equal to or exceed the conductors that are being tapped. The connections would be with mechanical lugs.

#80160 03/06/02 09:13 PM
Joined: Jan 2002
Posts: 122
W
Member
Sounds to me like you are adding a breaker because the MCC is tapped out. Are there provisions on the bus and literature from the manufacturer that will allow a connection to the bus? My understanding has always been that as soon as you start modifying equipment (in a way that it was not designed for) in the field you void the UL listing.
Depending on the buss rating and the actual load on the MCC you may get the manufacturer to allow this and re-certify the panel. Another way I have done this in the past is to install a "Top Hat" on the Mcc. (which is similar to a section of bus duct) that will allow you to attach an additional Mcc section next to or in the general vicinity of the existing Mcc. Make sure this is engineered, approved by the AHJ and who ever builds it can back it up with a UL listing.
Before you start. There are a few panel shops out there that can do this you just have to search. Depending on the size of your Mcc, length of new feeders etc. this can be a lower cost alternative than replacing the existing one.

#80161 03/07/02 07:22 AM
Joined: Mar 2001
Posts: 2,056
R
Member
What is the purpose of the extension.
Can you provide more detail?


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC Now Available!
 
* * * * * * *

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

 

Member Spotlight
RonKipperDatacom
RonKipperDatacom
Kansas City, KS
Posts: 30
Joined: January 2013
Top Posters(30 Days)
BigB 8
triple 3
Popular Topics(Views)
302,642 Are you busy
231,941 Re: Forum
216,592 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5