Running multiple grounded conductors in parallel

Status
Not open for further replies.

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
Main service conductors that are feed from load side of 13800/480 step down.

No equipment grounding conductor is required to be run with service conductors. A main bonding jumper would be installed at the service disconnect enclosure to bond the enclosure, grounded conductor and equipment grounding conductors. A ground electrode conductor will also be needed to connect the enclosure, grounded conductor and equipment grounding conductors to the grounding electrode(s).
 

aelectricalman

Senior Member
Location
KY
No equipment grounding conductor is required to be run with service conductors. A main bonding jumper would be installed at the service disconnect enclosure to bond the enclosure, grounded conductor and equipment grounding conductors. A ground electrode conductor will also be needed to connect the enclosure, grounded conductor and equipment grounding conductors to the grounding electrode(s).

Im sorry, Im talking about the load side of the transfer switch. The wiring that is going to the gear. The ATS is our new SE, now fed from the XFMR. From the Xfer switch on I will need EGC. Your right, the feeders from the XFMR are already ran and do not need EGC
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
So, are you suggesting that since the parallel rule does not apply to EGC's, that it is ok to take #3 AWG into 5 separate pipes to create and essentially equivelant 250KCMIL at the gear?

No. I'm suggesting that for a 2000A feeder with 5 parallel sets, if using conductor type EGCs, you would need 5 250mcm egc's, one in each conduit.

I'm also suggesting that for a 600A feeder with 2 parallel sets, you could use 2 #1awg (smaller than #1/0) egc's, one in each conduit.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
No. I'm suggesting that for a 2000A feeder with 5 parallel sets, if using conductor type EGCs, you would need 5 250mcm egc's, one in each conduit.

I'm also suggesting that for a 600A feeder with 2 parallel sets, you could use 2 #1awg (smaller than #1/0) egc's, one in each conduit.

In both of David's examples you're not running smaller EGC's to make a larger one you're running a full size EGC in each raceway.

Supply-side bonding jumpers between a transformer secondary and the secondary conductors OCPD can be sized according to the conductors within each raceway.
 

aelectricalman

Senior Member
Location
KY
In both of David's examples you're not running smaller EGC's to make a larger one you're running a full size EGC in each raceway.

Supply-side bonding jumpers between a transformer secondary and the secondary conductors OCPD can be sized according to the conductors within each raceway.

I was under the impression that you only need one (1) 250KCMIL condutor in on of the pipes and just bond the rest with bond bushings from the 250KCMIL. Why would you need a 250KCMIL in each conduit with you only need to have EGC rated for the breaker size. If you run one EGC at 250KCMIL and jumper the others, you have essentially done met code. My question was based on conduit restrictions. We were trying to use 5 - #3 THHN wires (one in each conduit) to suffice the one (1) 250KCMIL required EGC?
 

aelectricalman

Senior Member
Location
KY
None

None

In both of David's examples you're not running smaller EGC's to make a larger one you're running a full size EGC in each raceway.

Supply-side bonding jumpers between a transformer secondary and the secondary conductors OCPD can be sized according to the conductors within each raceway.

So does this mean no?
 
Last edited:

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
I was under the impression that you only need one (1) 250KCMIL condutor in on of the pipes and just bond the rest with bond bushings from the 250KCMIL. Why would you need a 250KCMIL in each conduit with you only need to have EGC rated for the breaker size. If you run one EGC at 250KCMIL and jumper the others, you have essentially done met code. My question was based on conduit restrictions. We were trying to use 5 - #3 THHN wires (one in each conduit) to suffice the one (1) 250KCMIL required EGC?

No offense intended...but have you read any of the responses. You asked the same question earlier, and were given an answer with code section referenced. (Posts 6,7,10,15,16,28,29)

You need a 250kcmil EGC (rated for the 2000A breaker size) in EACH of the five conduits. 5 - 250kcmil...5 #3 would be a code violation. See section 250.122(F).
 
Status
Not open for further replies.
Top