grounding/bonding of CT

Status
Not open for further replies.
I'm working on an agricultural job that some other company started and I have to finish and wanted some direction on this install:

Im setting a 800 A CT that feeds a panel inside.. there are 3 4'' rigid pipes that comes from the utility into the CT, 2 4'' nipples that go into the panel on the other side of the wall, a 1'' nipple that goes to the meter.. I have bonding bushings on all pipes including the 1'' I haven't set a CT in years and I know that a lot has changed code wise...

there are two ground rods... does my #6 from my ground rod terminate to all my bonding bushings in the ct and terminate in the panel?

Do i need bonding bushings on both sides (the ct AND the panel)

there is a single ground lug in the CT, based on an 800 a feed i need a 2/0 bonding jumper... I'm also assuming this terminates in the interior panel?

Also... there are only 3 4'' nipples from the CT to the interior panel... I will be feeding a main breaker (800 A) with parallel 500 mcm.. whats the code on putting parallel feeds in pipes.. shouldn't there be 3 pipes (one per phase)

any info would be appreciated.. thanks!
 

iwire

Moderator
Staff member
Location
Massachusetts
The same rules apply to a 800 amp CT can that apply to a homes 100 amp meter socket.

You only need to bond one end of each raceway.

Bonding jumpers connect the bonding bushings to the grounded conductor / neutral.

The NEC allows the grounding electrodes to any point of the grounded conductor from the service point to the service disconnect enclosure.

The CT can itself must be also be bonded to the grounded conductor / neutral.
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
This is how I do it, someone correct me if I'm wrong. I do the majority of my bonding in the service disconnect(s) just to stay out of the power company's CT can.

Jump from the grounded(neutral buss) on the CT perch to the lug at the bottom of the CT can with the 2/0.

Take your #6 from the rods into your service disconnect. C tap off this wire if there are multiple service disconnects.

Install the bonding bushing(s) on the service disconnect side of the nipples and run separate bonding jumpers, one each to the bond bushings sized per 250.66 based on the size of the conductors in the pipe. Run ABCN in each nipple.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
This is how I do it, someone correct me if I'm wrong. I do the majority of my bonding in the service disconnect(s) just to stay out of the power company's CT can.

Jump from the grounded(neutral buss) on the CT perch to the lug at the bottom of the CT can with the 2/0.

Take your #6 from the rods into your service disconnect. C tap off this wire if there are multiple service disconnects.

Install the bonding bushing(s) on the service disconnect side of the nipples and run separate bonding jumpers, one each to the bond bushings sized per 250.66 based on the size of the conductors in the pipe. Run ABCN in each nipple.

Thats pretty much what I see here.
 
making more sense

making more sense

Thats pretty much what I see here.

so my nipples that feed the panel need to be bonded with the 2/0, the 3 4'' rigid feeders from the utility can be bonded with my #6 (going from my rod, through my utility side 4'' bonding busings, to the 1'' bonding busings, then to my panel?

as far as the 2 4'' nipples for parallel 500's... that is code compliant?
 
making more sense

making more sense

so really the only termination to a ground/neutral buss in the CT will be to bond my CT, the rest will go back to my service disconnect panel.. right? i should have taken a picture
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
there are two ground rods... does my #6 from my ground rod terminate to all my bonding bushings in the ct and terminate in the panel?

No, GECs are to terminate at the service disconnect neutral, or possibly to the CT neutral. 250.24(A)(1).

There is a single ground lug in the CT, based on an 800 a feed i need a 2/0 bonding jumper... I'm also assuming this terminates in the interior panel?

No, you put a jumper between the can and the neutral. 250.92(B)(1).

Also... there are only 3 4'' nipples from the CT to the interior panel... I will be feeding a main breaker (800 A) with parallel 500 mcm.. whats the code on putting parallel feeds in pipes.. shouldn't there be 3 pipes (one per phase)
Do you mean to say, "One per parallel set"? Three parallel sets of 500 AL nets you 840A.

All bonding on the line side of the service disconnect get a 2/0 CU. A #6 is too small for the service conduits.
 

Smart $

Esteemed Member
Location
Ohio
so really the only termination to a ground/neutral buss in the CT will be to bond my CT, the rest will go back to my service disconnect panel.. right? i should have taken a picture
If your rods are outside, just bond to the grounded neutral conductor in the CT cabinet. As far as bonding the utility conduits and CT to panel nipples, I prefer to just use bonding locknuts... no wire bonding jumper required. The CT cabinet should be bonded to the grounded neutral conductor by way of the terminal lugs being mounted and directly secured to the cabinet.
 
Status
Not open for further replies.
Top