# Neutral wires at main service disconnect

**URL:** <https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486>\
**Category:** Electrical Inspections\
**Created:** [September 10, 2011, 12:52pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486 "2011-09-10T12:52:43Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![jfrederick](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jfrederick/32/58314_2.png) [@jfrederick](https://forum.nachi.org/u/jfrederick)\
**Post date:** [September 10, 2011, 12:52pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/1 "2011-09-10T12:52:43Z")

</div>

Newer SD 200 amp main service panel. Most of the grounded & grounding conductors were installed appropriately on the bus bars. However there were two isolated (bonded to panel) bus bars on both sides, with a few grounded & grounding conductors installed there. Now, I know the grounds are o.k. here, but what about the neutral wires and/or grounded conductors? Do the neutral wires need to be installed at the main neutral bus bar(s)?

Thanks in advance.

 ![IMG_0054.jpg](https://global.discourse-cdn.com/internachi/original/3X/b/b/bb96c4c9c564f11e92696b262ae8796cb47cb3fe.jpeg)

---

<div class="post-metadata">

**Author:** ![lkage](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/lkage/32/347658_2.png) [@lkage](https://forum.nachi.org/u/lkage)\
**Post date:** [September 10, 2011, 12:59pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/2 "2011-09-10T12:59:52Z")

</div>

> [@jfrederick](#):
>
> Newer SD 200 amp main service panel. Most of the grounded & grounding conductors were installed appropriately on the bus bars. However there were two isolated (bonded to panel) bus bars on both sides, with a few grounded & grounding conductors installed there. Now, I know the grounds are o.k. here, but what about the neutral wires and/or grounded conductors? Do the neutral wires need to be installed at the main neutral bus bar(s)?
> 
> Thanks in advance.

The grounded and grounding wires should be bonded at the service disconnect anyway…

---

<div class="post-metadata">

**Author:** ![rmeier2](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rmeier2/32/59909_2.png) [@rmeier2](https://forum.nachi.org/u/rmeier2)\
**Post date:** [September 10, 2011, 1:06pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/3 "2011-09-10T13:06:02Z")

</div>

Those neutrals conductors are not permitted on the EGC bus even in a service panel as shown in that photo. I see a main breaker, is this the service disconnect?

> [@](#):
>
> 200.2 General.  
> (B) Continuity. The continuity of a grounded conductor shall not depend on a connection to a metallic enclosure, raceway, or cable armor.

---

<div class="post-metadata">

**Author:** ![jfrederick](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jfrederick/32/58314_2.png) [@jfrederick](https://forum.nachi.org/u/jfrederick)\
**Post date:** [September 10, 2011, 1:07pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/4 "2011-09-10T13:07:46Z")

</div>

Thanks Robert, just wanted to confirm.

---

<div class="post-metadata">

**Author:** ![Jim\_Port](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@Jim\_Port](https://forum.nachi.org/u/Jim_Port)\
**Post date:** [September 10, 2011, 1:09pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/5 "2011-09-10T13:09:15Z")

</div>

> [@lkage](#):
>
> The grounded and grounding wires should be bonded at the service disconnect anyway…

The problem is that you now have return current on the metallic enclosure where you should not. RM has posted the code prohibition below.

---

<div class="post-metadata">

**Author:** ![lkage](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/lkage/32/347658_2.png) [@lkage](https://forum.nachi.org/u/lkage)\
**Post date:** [September 10, 2011, 1:19pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/6 "2011-09-10T13:19:39Z")

</div>

> [@Jim\_Port](#):
>
> The problem is that you now have return current on the metallic enclosure where you should not. RM has posted the code prohibition below.

Please help me out. Isn’t that a bonding screw at the bottom of the grounded conductor bus bar?

---

<div class="post-metadata">

**Author:** ![Jim\_Port](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@Jim\_Port](https://forum.nachi.org/u/Jim_Port)\
**Post date:** [September 10, 2011, 1:32pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/7 "2011-09-10T13:32:52Z")

</div>

That is a lug for a larger conductor. The bond screw on that Square D panel is out of the pic. It is a green domed head screw near the main breaker.

As it is now the neutral current will flow across the enclosure to the bond screw and then through the neutral buss and then out to the transformer.

---

<div class="post-metadata">

**Author:** ![lkage](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/lkage/32/347658_2.png) [@lkage](https://forum.nachi.org/u/lkage)\
**Post date:** [September 10, 2011, 1:36pm UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/8 "2011-09-10T13:36:35Z")

</div>

> [@Jim\_Port](#):
>
> As it is now the neutral current will flow across the enclosure to the bond screw and then through the neutral buss and then out to the transformer.

Thanks for the help.

---

<div class="post-metadata">

**Author:** ![ryoung7](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/ryoung7/32/188798_2.png) [@ryoung7](https://forum.nachi.org/u/ryoung7)\
**Post date:** [September 16, 2011, 1:40am UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/9 "2011-09-16T01:40:00Z")

</div>

> [@Jim\_Port](#):
>
> That is a lug for a larger conductor. The bond screw on that Square D panel is out of the pic. It is a green domed head screw near the main breaker.
> 
> As it is now the neutral current will flow across the enclosure to the bond screw and then through the neutral buss and then out to the transformer.

Alwaysa green doomed or green screw that is sized to fit only that thread on the panel. Will not fit any other entry.  
Am I correct in my statement Jim.:roll:

---

<div class="post-metadata">

**Author:** ![Jim\_Port](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@Jim\_Port](https://forum.nachi.org/u/Jim_Port)\
**Post date:** [September 16, 2011, 2:26am UTC](https://forum.nachi.org/t/neutral-wires-at-main-service-disconnect/62486/10 "2011-09-16T02:26:21Z")

</div>

The domed screw is just for the Square D. The correct location is shown on the panel label.

IIRC Cutler-Hammer Classic uses a bond strap into the buss.
