# Grounds for parallel feeds.



## erics37 (May 7, 2009)

310.10(H)(2) Conductor Characteristics. The paralleled conductors
in each phase, polarity, neutral, grounded circuit conductor,
*equipment grounding conductor*, or equipment bonding
jumper shall comply with all of the following:
*(1) Be the same length*
(2) Consist of the same conductor material
(3) Be the same size in circular mil area
(4) Have the same insulation type
(5) Be terminated in the same manner

Honestly I don't think it would matter a whole lot with grounding conductors because they're not supposed to carry any current under normal conditions, but at the same time, it's not something I'd want to be chancing around with.


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## Frasbee (Apr 7, 2008)

erics37 said:


> 310.10(H)(2) Conductor Characteristics. The paralleled conductors
> in each phase, polarity, neutral, grounded circuit conductor,
> *equipment grounding conductor*, or equipment bonding
> jumper shall comply with all of the following:
> ...


Thanks. Had a shutdown today, I'm in my boxers with beer in hand and didn't feel like running down 2 flights of stairs to get my codebook out of the car. :laughing:

I never knew that about the grounding conductors. The leadman was very specific about them being the same length.


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## Awg-Dawg (Jan 23, 2007)

Frasbee said:


> The leadman was very specific about them being the same length.


 

Im trying to think why it would matter?

I just cant think of a reason....:001_huh:


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## Frasbee (Apr 7, 2008)

Awg-Dawg said:


> Im trying to think why it would matter?
> 
> I just cant think of a reason....:001_huh:


 That was my thought as well. It doesn't make for a clean installation especially when you're in a hurry.


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## maxce50 (Jul 9, 2012)

always the same length


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## 360max (Jun 10, 2011)

no one pulls parallel conductors exactly the same length. We run the conduits as close as practical, pull the wires in, form them, terminate them, move on.


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## erics37 (May 7, 2009)

360max said:


> no one pulls parallel conductors exactly the same length. We run the conduits as close as practical, pull the wires in, form them, terminate them, move on.


It's probably impossible to get them the exact same length, even if you try. I doubt a few inches, or even a few feet, would have any significant effect. I imagine the intent is to keep a guy from running 3 parallel sets in one ditch and the 4th in another ditch. The code just doesn't differentiate for all different scenarios.


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## 360max (Jun 10, 2011)

erics37 said:


> It's probably impossible to get them the exact same length, even if you try. I doubt a few inches, or even a few feet, would have any significant effect. I imagine the intent is to keep a guy from running 3 parallel sets in one ditch and the 4th in another ditch. The code just doesn't differentiate for all different scenarios.


......read some of the above post


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## gottspeed (Mar 8, 2010)

The way you get them to be the exact same length is you install a large enough JB above or below the panel to loop the slack in before you terminate. I learned that from an OLD code guru in school.

And you don't need the grounds to be the same length.

Ungrounded conductors need to be the same length because the minute difference in impedance due to length will build to a larger difference as the tiny bit of additional heating in the longer conductor increases as the load goes up and time goes on.


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## GEORGE D (Apr 2, 2009)

gottspeed said:


> The way you get them to be the exact same length is you install a large enough JB above or below the panel to loop the slack in before you terminate. I learned that from an OLD code guru in school.
> 
> And you don't need the grounds to be the same length.
> 
> Ungrounded conductors need to be the same length because the minute difference in impedance due to length will build to a larger difference as the tiny bit of additional heating in the longer conductor increases as the load goes up and time goes on.


That's one way to make a nice clean install look sloppy.


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## BBQ (Nov 16, 2010)

gottspeed said:


> And you don't need the grounds to be the same length.


The NEC requires the grounds to be the same length.


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## Frasbee (Apr 7, 2008)

BBQ said:


> The NEC requires the grounds to be the same length.


What could happen if the grounds are not the same length in the event of a fault?


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## BBQ (Nov 16, 2010)

Frasbee said:


> What could happen if the grounds are not the same length in the event of a fault?


I doubt anything as each EGC of the parrellel sets is required to be full size. 

I don't understand the reason for the requirement.


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## gottspeed (Mar 8, 2010)

The CEC doesn't require the grounding conductors to be the same length. Only ungrounded and grounded circuit conductors.

I only suggested the JB because I was reading things like 'almost impossible' or 'ahh, dont bother' in this thread. If you wanna be scabby and ignore rules why bother keeping the ground the same length anyway.

12-108 Conductors in parallel (see Appendix B)
(1) Ungrounded and grounded circuit conductors of similar conductivity in sizes No. 1/0 AWG and larger,
copper or aluminum, shall be permitted to be installed in parallel sets provided that each parallel phase or
grounded conductor set is individually comprised of conductors that are
(a) free of splices throughout the total length;
(b) the same circular mil area;
(c) the same type of insulation;
(d) terminated in the same manner;
(e) the same conductor material; and
(f) the same length.
(2) Notwithstanding Subrule (1)(a), a single splice per conductor shall be permitted
(a) to meet the requirements of Rule 4-006; and
(b) where spliced in the same manner.
(3) In parallel sets, conductors of one phase, polarity, or grounded circuit conductor shall not be required to
have the same characteristics as those of another phase, polarity, or grounded circuit conductor.
(4) The orientation of single-conductor cables in parallel, with respect to each other and to those in other
phases, shall be such as to minimize the difference in inductive reactance and the unequal division of
current.
(5) Conductors of similar conductivity in sizes smaller than No. 1/0 AWG copper shall be permitted in parallel
to supply control power to indicating instruments and devices, contactors, relays, solenoids, and similar
control devices, provided that
(a) they are contained within one cable;
(b) the ampacity of each individual conductor is sufficient to carry the entire load current shared by the
parallel conductors; and
(c) the overcurrent protection is such that the ampacity of each individual conductor will not be
exceeded if one or more of the parallel conductors becomes inadvertently disconnected.
(6) Where parallel conductors include grounded circuit conductors, each parallel set shall have a separate
grounded circuit conductor.
(7) Where the size of neutral conductors is reduced in conformance with Rule 4-024, neutral conductors
smaller than No. 1/0 AWG shall be permitted in circuits run in parallel, provided that they are installed in conformance with the requirements of Subrule (1)(a), (b), (c), (d), and (e).


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