Neutrals and grounds doubled up on bus bar. Home Inspection

xformer

Senior Member
Location
Dallas, Tx
Occupation
Electrician
IMHO, this is not an NEC issue but a manufactures issue. 110.3(B) has been in the NEC for a long time. It is the Manufacturer who determines how many conductors are allowed per terminal. :)
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
This was added to the NEC because it has been a listing standard and manufacturer's instruction for many decades, but electricians were not following those requirements.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Note that, IF allowed by manufacturer, the NEC does allow two EGCs from different circuits to share a single terminal hole.
There is no immediate hazard from momentarily interrupting the EGC of a live circuit.
 

Rock86

Senior Member
Location
new york
Occupation
Electrical Engineer / Electrician
In case anyone goes looking for the 408.21 section... it has changed.

2020 NEC 408.41... " Grounded Conductor Terminations. Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor."
 
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tom baker

First Chief Moderator
Staff member
In my classes, I wanted the students to understand the why behind the rule. When you open the neutral on a MWBC those parallel loads become in series. The $14 hair dryer will be fine at 80V, but that $300 TV will let the smoke out at 160V. This is one of my favorite graphics from Mike Holt. There is a similar rule for wiring receptacles on MWBC (IE pigtailing neutral)
 

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Homeowner didn't want me to take time to change the doubled up neutrals. He said he researched the year the house was built 1994, and it wasn't required. I called the city elec inspector to ask what I should do, he said I need to separate the neutrals to individual holes. I did that, but am now looking in my 1993 NEC and can't find a similar paragraph like 408.41 2020 NEC. Help. Thanks.
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
Homeowner didn't want me to take time to change the doubled up neutrals. He said he researched the year the house was built 1994, and it wasn't required. I called the city elec inspector to ask what I should do, he said I need to separate the neutrals to individual holes. I did that, but am now looking in my 1993 NEC and can't find a similar paragraph like 408.41 2020 NEC. Help. Thanks.
Is this a job where you've been wiring, or a real estate inspection?
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
As stated, the Code didn't require it, but the manufacturer probably did. Realistically, how much time is it going to take? 15 minutes?
It can take up to a couple of hours. The reason they're doubled is usually all the holes are full.

The last one I did it was only a week ago, and it took about 45 minutes to remove some neutrals, add a ground bar, jumper with bare #4, make up neutrals and grounds again

Sometimes the neutral and ground from each circuit are together in one hole. Got to remove all of them and make up all over again.

Many times, the multiple wires under one screw have been twisted together, and the wires aren't long enough to just cut the Twisted part off and re-strip
 
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