ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Where is Everyone?
by gfretwell - 11/27/20 06:18 PM
Happy Thanksgiving
by gfretwell - 11/26/20 08:52 PM
Insulated Tools: A Waste of Money?
by HotLine1 - 11/26/20 12:28 PM
Ground fault remover :-)
by NORCAL - 11/26/20 08:13 AM
Work Gloves?
by sabrown - 11/25/20 01:54 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 14 guests, and 11 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 4 1 2 3 4
120 vac and 24vdc in same conduit #187186 06/16/09 07:07 PM
Joined: Aug 2008
Posts: 10
S
shop_test Offline OP
Member
I cant find this in the NEC.
Is there a reference in the NEC to separate 24vdc and 120 vac into their own conduits?

2017 / 2014 NEC & Related Books and Study Guides
Re: 120 vac and 24vdc in same conduit [Re: shop_test] #187197 06/16/09 11:13 PM
Joined: Mar 2003
Posts: 849
Y
Yoopersup Offline
Member
Try Article 725. 2005 NEC
725.26
725.41
725.55
Depending on the class of the 24volt.

Re: 120 vac and 24vdc in same conduit [Re: Yoopersup] #187206 06/17/09 02:24 PM
Joined: Aug 2008
Posts: 10
S
shop_test Offline OP
Member
Thanks for the quick feedback.
Unfortunately I only have the 2008 NEC and 725.26 / 725.55 are no longer listed.

Re: 120 vac and 24vdc in same conduit [Re: shop_test] #187222 06/17/09 06:11 PM
Joined: Mar 2003
Posts: 849
Y
Yoopersup Offline
Member
2008 NEC Article 725
725.48
725.136
Try thoses
Also read Article 725 Definitions for
Classes 1,2,3.

Re: 120 vac and 24vdc in same conduit [Re: Yoopersup] #187226 06/17/09 07:07 PM
Joined: Aug 2008
Posts: 10
S
shop_test Offline OP
Member
Thanks.
It looks like the answer is yes it is acceptable for our situation.

Re: 120 vac and 24vdc in same conduit [Re: shop_test] #187254 06/18/09 11:30 AM
Joined: May 2009
Posts: 20
B
BullDog Offline
Member
Sorting out when it's Ok and when it isn't seems an interesting subject.

Can you provide a few more project details that describe the application?

Thanks

Re: 120 vac and 24vdc in same conduit [Re: BullDog] #187255 06/18/09 11:42 AM
Joined: Aug 2008
Posts: 10
S
shop_test Offline OP
Member
A rigid coduit connects a control panel with a metering device.
The device uses 120VAC for control power and has a contact that will have 24vdc going through it and used back at the control panel as an input to a PLC.

Re: 120 vac and 24vdc in same conduit [Re: shop_test] #187256 06/18/09 11:56 AM
Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
Since these circuits are functionally related, even if the 24 vdc is class 2 or class 3, you could take advantage of exception #2 to 725.130(A) and also apply 725.48(B)(1) and run the 24 vdc as a class 1 circuit.


Few things are harder to put up with than the annoyance of a good example.
Re: 120 vac and 24vdc in same conduit [Re: Tom] #187261 06/18/09 01:28 PM
Joined: May 2009
Posts: 20
B
BullDog Offline
Member
Shop_Test - As I understand it the two could in certain applications be serving the same device and be combined, but the NEC calls out certain separation devices and or distance that must be maintained between the conductors?

Tom- In the case of wiring as a Class 1 circuit (upgrade the wiring), NEC2005 725.27(A) would require 18 or 16 AWG and 725.27(B) would require 600 volt rated insulation of specific types?

Am I barking up the right tree?

Re: 120 vac and 24vdc in same conduit [Re: BullDog] #187266 06/18/09 01:53 PM
Joined: Jun 2007
Posts: 301
J
JValdes Offline
Member
Same temperature rating, your good. Personally, I always separate power from control. Regardless of the situation. Just my way.

Page 1 of 4 1 2 3 4

Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

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

 

Member Spotlight
SafetyWired
SafetyWired
Pa, USA
Posts: 44
Joined: July 2013
Show All Member Profiles 
Top Posters(30 Days)
Trumpy 9
Popular Topics(Views)
272,071 Are you busy
205,961 Re: Forum
194,010 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3