Table 250.122

DBoone

Senior Member
You have a 20 amp circuit with 12 awg and a 15 amp circuit with 14 awg in the same box. Does Table 250.122 prohibit tying the 12 awg and 14 awg equipment grounds together? I am very familiar with 250.148 but would like some insight into 250.122. Thank you for your time.
 

infinity

Moderator
Staff member
No it's not prohibited and depending on who you ask some say that it's required.

Welcome to the Forum. :)
 

Smart $

Esteemed Member
... depending on who you ask some say that it's required.
The only instance I can think of when it is not required is when one is an isolated grounding conductor. Are there other instances I'm not aware of? Or are you referring to instances where the conductors simply pass through the box without splice or termination?
 
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Little Bill

Moderator
Staff member
One thing to keep in mind. If the box is a metal one then your bond to the box would need to be sized according to the largest size EGC run.
So in the OP's case, bond to box with 12 AWG.
 

iwire

Moderator
Staff member
The only instance I can think of when it is not required is when one is an isolated grounding conductor. Are there other instances I'm not aware of? Or are you referring to instances where the conductors simply pass through the box without splice or termination?
When you are using non-metalic boxes there is nothing in the NEC requiring EGCs from seperate circuits to be tied together.
 

iwire

Moderator
Staff member
That is not how I read 250.148.
Interesting.

250.148 Continuity and Attachment of Equipment
Grounding Conductors to Boxes.
Where circuit conductors
are spliced within a box, or terminated on equipment
within or supported by a box, any equipment grounding conductor(
s) associated with those circuit conductors shall be connected
within the box or to the box with devices suitable for
the use in accordance with 250.148(A) through (E).
How is a 15 amp lighting circuit associated with a 20 amp receptacle circuit?

I have argued this before with George S and he pretty much convinced me that it does not require all circuit EGCs to be connected together.
 

don_resqcapt19

Moderator
Staff member
I read that section as saying that any EGC that is associated with any circuit in the box must be connected to all other EGCs that are associated with all other circuits in that box. Yes, I know we have discussed this before, but I don't think the wording is clear.
 

Smart $

Esteemed Member
When you are using non-metalic boxes there is nothing in the NEC requiring EGCs from seperate circuits to be tied together.
That is not how I read 250.148.
Interesting.



How is a 15 amp lighting circuit associated with a 20 amp receptacle circuit?

I have argued this before with George S and he pretty much convinced me that it does not require all circuit EGCs to be connected together.
I read that section as saying that any EGC that is associated with any circuit in the box must be connected to all other EGCs that are associated with all other circuits in that box. Yes, I know we have discussed this before, but I don't think the wording is clear.
It comes down to the particulars of what the conductors do after entering the box...

If both circuits pass through the box without splice or termination, no interconnection or bonding required.

If one circuit passess through while the other is spliced and/or terminated within the box, no interconnection required, but bonding of the spliced and/or terminated circuit's EGC to grounding terminals, metallic box, etc. is required.

If both circuits are spliced and/or terminated, interconnection and bonding applies to both.

[edit to add: the preceding does not apply to isolated grounding conductors]
 
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Dennis Alwon

Moderator
Staff member
I have always read it as meaning all the equipment grounding conductor's from all circuits shall be tied together.
 
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