Grounding of two different circuits

[Flex]

I have two different lighting circuits in one 4 gang box. Each is feed from its own separate mc. Are the grounds required to be terminated together? I found 250.144 but am not sure if thats what it says.

 

[cpal]

I have two different lighting circuits in one 4 gang box. Each is feed from its own separate mc. Are the grounds required to be terminated together? I found 250.144 but am not sure if thats what it says.

in the same enclosure ? Tie them all together !

 

[Flex]

they have to be right? Cause each circuit has to be bonded to the box anyway so might as well tie them all together. 2 electricians told me today to keep them seperate. I dont believe them.

also would like a code reference please

 

[raider1]

Take a look at 250.148.

Chris

 

[Flex]

I read that as a yes except in a nonmetallic box. Any other viewpoints?

 

[Pierre C Belarge]

they have to be right? Cause each circuit has to be bonded to the box anyway so might as well tie them all together. 2 electricians told me today to keep them seperate. I dont believe them.

also would like a code reference please

People confuse the grounding terms on a daily basis.
Maybe they meant the grounded conductors of different circuits.

 

[Flex]

So they do need to be tied together

 

[LarryFine]

If you're talking grounded conductors, keep them separated.

If you're talking EGC's, join them; there's no reason not to.

 

[Pierre C Belarge]

Yes, they do need to be tied together.

 

[roger]

So they do need to be tied together

No, but it is best to do so, two or more bonding conductors in parallel have a lower impedance than one.

Roger

 

[izak]

but what happens to the 1/0 rule on parallel installations? same length, and all that stuff?

what if they are EGCs from different panels?

 

[raider1]

what if they are EGCs from different panels?

And what if they are? Connecting the EGC's from different panels together will not cause a problem. Everything that is grounded and bonded will be electrically connected at one point in the electrical system anyway.

Chris

 

[ibew441dc]

but what happens to the 1/0 rule on parallel installations? same length, and all that stuff?

1/0 rule, same length, and all that stuff does not apply to individual EGC's run with their appropriate circuit conductors, that are not in parallel.
[example-(4) 20 amp circuits in the same raceway can be installed with 4 separate EGC's or one EGC in accordance with 310.4(E)]

310.4(A) General. Aluminum, copper-clad aluminum, or copper
conductors of size 1/0 AWG and larger, comprising each
phase, polarity, neutral, or grounded circuit conductor shall
be permitted to be connected in parallel (electrically joined
at both ends).

310.4(A)does not initially apply to EGC's of individual circuits

310.4(E) Equipment Grounding Conductors. Where parallel
equipment grounding conductors are used, they shall be
sized in accordance with 250.122. Sectioned equipment
grounding conductors smaller than 1/0 AWG shall be permitted
in multiconductor cables in accordance with 310.13,
provided the combined circular mil area in each cable complies
with 250.122.

250.122 (short version) based on the size of the OCPD

250.122(C) Multiple Circuits.
Where a single equipment grounding
conductor is run with multiple circuits in the same
raceway, cable, or cable tray, it shall be sized for the largest
overcurrent device protecting conductors in the raceway,
cable, or cable tray. Equipment grounding conductors installed
in cable trays shall meet the minimum requirements
of 392.3(B)(1)(c).

This rule implies an option to have only one EGC, versus, the Largest plus the rest.

Anybody jump in if I missed something, It has been my experience that this is a hard one to explain especially typing......

 

[roger]

310.4(A)does not initially apply to EGC's of individual circuits

Remove "initially" and "of individual circuits" and you've got it. :smile:

Roger

 

[ibew441dc]

Remove "initially" and "of individual circuits" and you've got it. :smile:

Roger

Your right:roll: I started over thinking and over typing:wink:...thanks:smile:

DISCLAIMER-Under the rules of this Forum I can not go back and delete my error it has been to long and I'm not a moderator:grin:

 

[Flex]

Pierre do you disagree with Roger? My thinking is somehow they will be tied together everywhere but in a plastic box just due to the requirement to bond the egc's to the box.

 

[Pierre C Belarge]

Flex
i agree about the metallic type box bonding.

Lets take a plastic box.
If there is a 3 gang box and there are 3 different circuits and there are splices and/or termination to equipment, the equipment ground conductors "shall be spliced or joined within the box"
250.148

 

[brian john]

Grounded conductor = neutral, keep these seperate.

EGC = equipment grounding conductor= conduit, green conductor, bare conductor tie them together, is better, (that's is what I would do. But seperate will work.

Ground is ground they are all common.

 

[Flex]

Seperate will work, but dont both have to be bonded to the metal box. So leaving them separate would violate code.

 

[K8MHZ]

Ground is ground they are all common.

True, but not precise.

There is a difference between grounded conductors and grounding conductors and the way they are meant to be used in a circuit.

Personally, I think a change in terminology is due. The terms are too similar and since one is intended to carry current and the other is not, they should be easier to discern by label.