SSBJ not required between grounded Meter and Disconnect?

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Macktek

Member
Location
NC USA
Occupation
I.T.
(My first post, apologies in advance)

I was watching: Grounding Service - Terminating grounding electrode conductor NEC Code 250.24(A)(1) by Mr. Holt. At that point in the video, he states that a supply side bonding jumper is not required between a grounded meter and the disconnect.
I Terminating grounding electrode conductor NEC Code 250.24(A).jpg

I am confused because per NEC 250.24(D) Grounding Electrode Conductor. A grounding electrode conductor shall be used to connect the equipment grounding conductors, the service-equipment enclosures, and where the system is grounded, the grounded service conductor to the grounding electrodes...

Additionally, per https://www.mikeholt.com/mojonewsarchive/NEC-HTML/HTML/Article230-Services~20020219.htm the definition of service equipment is: Service equipment - The necessary equipment, usually consisting of circuit breakers or switches and fuses and their accessories, connected to the load end of service conductors to a building or other structure, or an otherwise designated area, and intended to constitute the main control and cutoff of the supply. Service equipment does not include the metering equipment, such as the meter and/or meter enclosures [230.66].

Since we know that a grounding electrode conductor must connect the neutral conductor to a grounding electrode (at either service drop, meter or service disconnect), and a grounding electrode conductor shall be used to connect the service-equipment enclosures, how can a Neutral wire alone satisfy that requirement especially when combined with 250.24(C) Grounded Conductor brought to service equipment "...grounded conductors shall be routed with ungrounded conductors to each service disconnecting means and shall be connected to each disconnecting means grounded conductor(s) terminal or bus."

I guess I am wondering where in the code, it allows to substitute a Neutral to be used? I went to 250.142(A), (per video) and I don't see where it says this.

Any help would be appreciated.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
All metal parts on the line side of the service disconnect are connected to the neutral. The GEC is connected to the neutral and the MBJ (main bonding jumper) connects the metal enclosure to the neutral so now everything is connect together. Everywhere downstream of the service disconnect the neutrals and EGC's are kept isolated from each other.

Looking at Mike's graphic an SSBJ if installed between the meter and the service disconnect would be in parallel with the neutral and would create objectionable current therefore it cannot be installed.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Mack, welcome to the forum!

On the line side of the main disconnect, there is no grounding conductor, there is only the neutral, which isn't substituting for anything at all. Think of the equipment enclosures as bubbles in the neutral conductor that contain electrical parts.

The premises grounding system begins at the main disconnect, and makes sure that any metallic equipment has a conductive pathway back to the neutral, so we can be assured that any fault from a hot wire will trip a breaker or blow a fuse.
 
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