Bonding a metal junction box containing no splices (except the EGC)?

Jon456

Senior Member
Location
Colorado
This is something I really hadn't thought about before. Let's say we have multiple branch circuits in conduit that also carries an EGC back to the distribution panel.

Typically a junction box either contains splices on the energized conductors (thus requiring that the box be individually bonded with a pigtail connected to the EGC), or the box is simply a pull-through point (thus not requiring the box to be bonded individually with a pigtail).

But what if you have a box where two or more branch circuits enter together through a common conduit, but simply split off into different downstream conduits without any splices in the energized conductors. The only splice within the box is in the EGC because you must split the EGC into each downstream conduit. It seems to me that since the box contains no splices in the energized conductors, then the box itself does not need to be individually bonded to the EGC because it is no different than a straight pull-through.

The reason for this question is both academic as well as practical. If the box just contains some 10 AWG or smaller conductors, I'd just throw on a pigtail without a second thought. But for large conductors, it makes a difference. For example, it could mean the difference between a 3-port or 4-port Polaris connector for the EGCs.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
If the circuit conductors are not spliced then no connection to the box is required as long as the box is connected to a metal raceway that qualifies as the EGC.

250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes. If circuit conductors are spliced within
a box
or terminated on equipment within or supported by a box, all equipment grounding conductor(s) associated with any of those circuit conductors shall be connected within the box or to the box with devices suitable for the use in accordance
with 250.8 and 250.148(A) through (E)
 

Chamuit

Senior Member
Location
Texas
If you carry an EGC with each circuit or grouping, they'd just run through the j-box and on to their destination.
For example, two full boats from the panel with an EGC each (2 grounds) split at the first junction box and run to their respective distribution points. No grounding needed.
Same situation but only one EGC, you would have to ground the box and tie all grounds together.
 

jusme123

Senior Member
Location
NY
Occupation
JW
If you carry an EGC with each circuit or grouping, they'd just run through the j-box and on to their destination.
For example, two full boats from the panel with an EGC each (2 grounds) split at the first junction box and run to their respective distribution points. No grounding needed.
Same situation but only one EGC, you would have to ground the box and tie all grounds together.
Why waste the wire?
What if it was 250’ before the circuits split in different directions?
 

Jon456

Senior Member
Location
Colorado
How do you get the EGC to head in two different directions without cutting it?
That was the point of my question. You must splice the EGC to have it split into two (or more) different directions.

I see no reason to add multiple EGCs in a single raceway unless you need an isolated ground.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
If you carry an EGC with each circuit or grouping, they'd just run through the j-box and on to their destination.
For example, two full boats from the panel with an EGC each (2 grounds) split at the first junction box and run to their respective distribution points. No grounding needed.
Same situation but only one EGC, you would have to ground the box and tie all grounds together.
I don't see a bonding jumper to the box being required if the circuit conductors are not spliced.
 

Greentagger

Senior Member
Location
Texas
Occupation
Master Electrician, Electrical Inspector
That was the point of my question. You must splice the EGC to have it split into two (or more) different directions.

I see no reason to add multiple EGCs in a single raceway unless you need an isolated ground.

Some engineers do. It’s speced that way all the time.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
No grounding needed.
Same situation but only one EGC, you would have to ground the box and tie all grounds together.
I believe the opposite was the point of the original post.

If a circuit conductor gets spliced, then you have to tie all the grounds together, which means a jumper between the conduit ground and the EGC wire.

If the only splice in the junction box is the EGC wire, then the requirement to connect _all_ grounds together doesn't get triggered.

-Jon
 
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