# Instrumentation and Control Ductbank Grounding



## wildleg (Apr 12, 2009)

no. didn't you ask this question on mike holt ? what answer are you looking for ?

http://forums.mikeholt.com/showthread.php?t=127130&highlight=require


----------



## aperez01 (Jun 30, 2010)

The reason i asked this question on this forum as well is to get other comments on the subject.

The company I previously worked for completed a project were the electrical inspector requested a 4/0 ground wire be installed in control and instrumentation ductbanks (drawings only required it in power ductbanks). The task was completed and a change order was submitted. The change order was rejected on the basis that the NEC requires that underground pvc conduit ductbanks have bonding conductors installed to bond the metallic conduits attached to the pvc, without regard to voltage or type of circuit.

I am trying to get some feedback/technical responses to help the company win the arguement that they meet specfications and NEC by install 4/0 in power ductbanks, but instrumetation and control ductbank 4/0 ground is a preference requirement not NEC.


----------



## wildleg (Apr 12, 2009)

you are starting to provide enough information to answer your question. elaborate on where the metallic components are. what type of metallic conduit are you using and why is part of the system metallic. what code cycle are you on.


----------



## wildleg (Apr 12, 2009)

while 250.2 A 3 states that non current carrying conductive materials shall be bonded, and 300.10 states the same, 300.10 exception 1 states that if the metallic portions are short and used to protection from physical damage they are not required to be bonded. There is no requirement for a 4/0 conductor (unless the info you provided was incomplete). There may be requirement for an EGC, as applies to whatever cables or conductors you are installing depending on the articles that apply. (2008) BTW, is this a gov or state job ? who is the ahj and what section did the inspector quote ? (if these are specs and the inspector is an agent of the owner, then you don't have a leg to stand on)


----------



## RIVETER (Sep 26, 2009)

Non current carrying components of an electrical system.


----------



## aperez01 (Jun 30, 2010)

We installed pvc coated rigid conduit sweeps to sch 40 pvc conduit. The ground wire we installed was bonded to a ground rod in each instrumetation and control pull box and whips were cadwelded to the main 4/0 run in the ductbank to bond the pvc coated stub-ups with a ground clamp.


----------

