Junction Box Grounding

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Rccranford1

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Glen Burnie, Maryland
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Electrical Inspector
250.148, there are junction boxes with conduit runs entering and exiting, the contractor that have spliced connections for feeder cables, branch circuits. The contractor is stating that these metal boxes do not need to be grounded, our inspection team says the code requires them to be grounded, we are certified Md. Inspectors at BWI airport and would like your input
 
Rccranford1 said:
250.148, there are junction boxes with conduit runs entering and exiting, the contractor that have spliced connections for feeder cables, branch circuits. The contractor is stating that these metal boxes do not need to be grounded, our inspection team says the code requires them to be grounded, we are certified Md. Inspectors at BWI airport and would like your input
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Welcome to the forum.

What's the objection to the conduits providing the grounding function?
 
If the circuit conductors are not spliced and pass through the box then a bonding jumper is not required.
 
These Junction Boxes contain 4 parralel feeders 600 mcm, each with a ground conductor, this jb is a splice point. As a field electrician I always tapped one EGC and bonded the metal box per 250.148. I never ever had a contractor argue this point. My contractor
contention is the bonding of the metal Junction Box is not required, our Job specs refer to NFPA 70. There arguement now is this code 250.148 (C) is geared to light commercial and residential. They are not making sense ro me even their journeyman electricians wanted to bond this box but were over ruled by their Superintendant. Thoughts please,I know the code and have been tested on grounding multiple times
 
I changed my view in this. As I read 250.248 it states that all equipment grounding conductor's that are spliced within the box shall be connected together OR to the box.
 
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Rccranford1 said:
There argument now is this code 250.148 (C) is geared to light commercial and residential.
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Not true, article 250 covers all occupancies. Please post the sections that they say make this section applicable to light commercial and residential. Code language would be dwelling units, and non dwelling units.
 
Dennis Alwon said:
I changed my view in this. As I read 250.248 it states that all equipment grounding conductor's that are spliced within the box shall be connected together OR to the box.
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...in accordance with (A) thru (D). I think that means (C) applies.
 
I don't see how that applies to this issue on type of occupancy, no where does it state in section 250.148 (C), light commercial (not defined in NEC) or residential.
 
I think it's a poorly constructed sentence (my comments in brackets):

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

(A) Connections and Splices [how to make connections]
(B) Equipment Grounding Conductor Continuity [pigtail to the luminaire, receptacle, etc]
(C) Metal Boxes [pigtail between box and grounding conductors]
(D) Nonmetallic Boxes [pigtail to a fitting or device]


I think the -intent- of this section is to attach that pigtail between the grounded conductors and the box (if it's metal).

250.148 ...shall be connected within the box [if it's nonmetallic] or to the box [if it's metallic] in accordance with 250.8 [how to connect wires] and 250.148(A) through (D).
 
Rccranford1 said:
These Junction Boxes contain 4 parralel feeders 600 mcm, each with a ground conductor, this jb is a splice point. As a field electrician I always tapped one EGC and bonded the metal box per 250.148. I never ever had a contractor argue this point. My contractor
contention is the bonding of the metal Junction Box is not required, our Job specs refer to NFPA 70. There arguement now is this code 250.148 (C) is geared to light commercial and residential. They are not making sense ro me even their journeyman electricians wanted to bond this box but were over ruled by their Superintendant. Thoughts please,I know the code and have been tested on grounding multiple times
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If the circuit conductors are spliced in a metal box then the EGCs (if present) must be connected to the box per 250.148(C). Been this way for decades.
I would add that they also have to connected to each other as well. So you could attach each to the box or tie them all together and use a pigtail to the box. Usually in a large larger sizes like you have I would attach them to a ground bar mounted to the box.
 
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