ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Inspection camera help
by petey_c. 09/22/18 07:52 AM
Motion detectors and dimmers
by gfretwell. 09/20/18 04:02 PM
Extension cords
by annemarie1. 09/20/18 08:54 AM
220/230/240V 60Hz Systems
by gfretwell. 09/16/18 12:37 PM
Acronis Backup 2017
by gfretwell. 09/16/18 12:46 AM
New in the Gallery:
Plug terminals
Housebilding DIY wiring
Who's Online Now
0 registered members (), 15 guests, and 19 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
sub panel feeder wire sizes...... #7146
01/24/02 05:23 PM
01/24/02 05:23 PM
D
duanet  Offline OP
Junior Member
Joined: Dec 2001
Posts: 5
Hi,
I am installing a new 125 Amp sub panel 65 feet away from a new 200 amp service. The sub is located in the same shop as the main panel. Do i need to pull a separate grounding conductor for the sub or can the EMT between the main and the sub be used for the grounding bond? I ask as i would like to use 1-1/4 EMT which will only allow three #1 copper conductors.
(per conduit fill table 3B)
Thus allowing 2-#1 lines and a common max.
If i have to pull a separate #6 ground i would have to step up to the 1-1/2 EMT. Basically i wish to know if on a sub panel situation such as this is it allowed to use the EMT conduit as the ground rather than a separate conductor?

thanks

Work Gear for Electricians and the Trades
Re: sub panel feeder wire sizes...... #7147
01/24/02 06:22 PM
01/24/02 06:22 PM
D
dana1028  Offline
Member
Joined: Jan 2002
Posts: 163
San Carlos, CA
I'm now looking at Appendix C of the 1999 NEC, pg. 585 - THHN #1...4 conductors (#1 size) are allowed in 1-1/4" EMT

Re: sub panel feeder wire sizes...... #7148
01/24/02 06:28 PM
01/24/02 06:28 PM
D
duanet  Offline OP
Junior Member
Joined: Dec 2001
Posts: 5
You may want to check again as my NEC book Table 3B (maximum # of conductors in trade sizes of conduit or tubing) states that a maximum of 3 #1 THHN in 1-1/4

Re: sub panel feeder wire sizes...... #7149
01/24/02 06:48 PM
01/24/02 06:48 PM
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
Shinnston, WV USA
Where the heck is table 3B?

Table C1 on page 585 is the correct one to use & as dana1028 pointed out 1 1/4" emt is good for 4 #1's.

You don't usually need to pull in the equipment ground, but many electricians prefer to include one in all their conduit work.


Few things are harder to put up with than the annoyance of a good example.
Re: sub panel feeder wire sizes...... #7150
01/24/02 06:51 PM
01/24/02 06:51 PM
D
duanet  Offline OP
Junior Member
Joined: Dec 2001
Posts: 5
Table 3B is in chapter 9 (tables and examples) page 750 of 1990 NEC

Re: sub panel feeder wire sizes...... #7151
01/24/02 09:54 PM
01/24/02 09:54 PM
A
Anonymous
Unregistered

duanet,

Its time to invest in a new NEC book.

Re: sub panel feeder wire sizes...... #7152
01/24/02 11:37 PM
01/24/02 11:37 PM
E
eman1963  Offline
Member
Joined: Jan 2002
Posts: 22
rhode island
i would use the 1 1/4 emt as the ground and run only 3 conductors

Re: sub panel feeder wire sizes...... #7153
01/24/02 11:38 PM
01/24/02 11:38 PM
R
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
What size breaker are you installing ?

Re: sub panel feeder wire sizes...... #7154
01/25/02 07:56 PM
01/25/02 07:56 PM
D
dana1028  Offline
Member
Joined: Jan 2002
Posts: 163
San Carlos, CA
BTW - Appendix C, pg. 585 does say 4 #1 are allowed in 1-1/4" EMT; however if you do the arithmetic from Table 4 & Table 5 (EMT usable space & area of THHN tables)you cannot use 4 #1s in 1-1/4" EMT.

However, even though you are allowed to use the EMT as the EGC, I highly recommend you do pull the #6 (the arithmetic works) as your EGC - don't trust the EMT connection over the years to be maintained and work when needed in the event of a fault.

Re: sub panel feeder wire sizes...... #7155
02/06/02 12:03 AM
02/06/02 12:03 AM
3
3rd degree Burns  Offline
Member
Joined: Feb 2002
Posts: 36
Dallas, Texas, USA
I have to agree with Dana, don't trust conduits to carry the ground as the years progress...I've already seen far too many lost grounds from installations 15 to 30 years old. Go ahead and pull it, you won't regret it later.


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
noderaser
noderaser
Portland, Oregon, United States
Posts: 404
Joined: March 2007
Show All Member Profiles 
Top Posters(30 Days)
Admin 13
Trumpy 11
Popular Topics(Views)
249,393 Are you busy
187,330 Re: Forum
176,666 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.029s Queries: 14 (0.004s) Memory: 1.0064 MB (Peak: 1.1804 MB) Zlib enabled. Server Time: 2018-09-23 14:14:52 UTC