Conduit Spacing / Separation - Electrical - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical


Thread Tools Display Modes
Old 04-07-2008, 02:33 PM   #1
Join Date: Mar 2008
Posts: 10
Rewards Points: 10

Conduit Spacing / Separation

Does the NEC specify a minimum distance between buried conduits, or any additional derating that needs to be done due to close proximity? Im planning to run 3 PVC conduits between my house and the garage in the same trench and at the same depth. Figure 310.60 in the 2008 NEC shows a spacing of 7.5 between conduits in such a duct bank, but I couldnt find any reference to spacing in the code (my guess is that this simply means that conduits more than 7.5 apart are no longer considered to be part of the same bank). Id like my conduits to be much closer together for aesthetics, such that the LBs at the building entry points only have maybe 1/2 or so between them, but I want to make sure Im not missing any derating concerns with this setup (all wiring is copper):

Conduit #1: 1 PVC containing three #6 THWN feeder wires and one #10 EGC. Ampacity calculated at 65A, breakered at 70A using next standard size rule. Will rarely if ever see that level of loading (sized to accommodate a large arc welder with a little to spare for lighting, but will not see more than 10-15A).

Conduit #2: PVC containing three #12 THWN wires and one #14 EGC from a three-way light switch inside the house (could have been included in conduit #1, but I would have then had to breaker the feeder at 60A due to additional required derating). Circuit is part of a lighting branch protected by 15A breaker, actual max load of about 3A on these wires.

Conduit #3: PVC containing two CAT5e phone/data lines.


smitty286 is offline   Reply With Quote
Old 04-07-2008, 05:32 PM   #2
You talking to me?
nap's Avatar
Join Date: Dec 2007
Location: sw mi
Posts: 7,551
Rewards Points: 6,290

throw them in the hole and bury them but you need to change that #14 EGC to a #12.

and you need to upsize the #10 EGC to a #8.


nap is offline   Reply With Quote
Old 04-07-2008, 05:33 PM   #3
Join Date: Oct 2007
Posts: 2,294
Rewards Points: 1,000

No spacing required.

Throw em in and kick the dirt back in.
220/221 is offline   Reply With Quote
Old 04-08-2008, 10:11 AM   #4
Join Date: Mar 2008
Posts: 10
Rewards Points: 10

Thanks for responding, guys, and thanks for that catch nap....I originally planned to put the #6's and #12's in the same pipe, making it a 60A feeder with a #10 EGC...forgot to upsize when I moved the 12's to their own conduit (the #14 in that pipe was a typo).
smitty286 is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Conduit Fill & Ampacity capndave Electrical 37 03-26-2008 02:16 PM
Pvc Conduit bobo60 Electrical 1 11-14-2007 09:52 PM
Conduit issues - help needed nymackem Electrical 19 11-05-2007 06:45 AM
Conduit through basement wall. bdalekid Electrical 13 01-31-2007 08:35 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1