Grounding Parallel Conductors Run in 2 Pipes

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jonny1982

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I am feeding a 400 amp 3 phase main distribution panel with parallel feeders. There is (2) 2-1/2 inch PVC's ran from Meter to Panel. Can I run (4) 4/0 AL (3 hots and 1 neutral) and (1) 3/0 (equipment ground) in one pipe and (4) 4/0 in the other or do I need to run a ground in each pipe?
 
You need a full sized EGC in each raceway in a parallel install.

300.3(B) Conductors of the Same Circuit. All conductors of
the same circuit and, where used, the grounded conductor
and all equipment grounding conductors and bonding conductors
shall be contained within the same raceway, auxiliary
gutter, cable tray, cablebus assembly, trench, cable, or
cord, unless otherwise permitted in accordance with
300.3(B)(1) through (B)(4).

(1) Paralleled Installations. Conductors shall be permitted
to be run in parallel in accordance with the provisions
of 310.10(H). The requirement to run all circuit conductors
within the same raceway, auxiliary gutter, cable tray, trench,
cable, or cord shall apply separately to each portion of the
paralleled installation, and the equipment grounding conductors
shall comply with the provisions of 250.122. Parallel runs
in cable tray shall comply with the provisions of 392.20(C).
 
In addition to the requirements of 300.3(B) there is also this.

2011 NEC

250.122 Size of Equipment Grounding Conductors.

(F) Conductors in Parallel. Where conductors are installed
in parallel in multiple raceways or cables as permitted in
310.10(H), the equipment grounding conductors, where used,
shall be installed in parallel in each raceway or cable. Where
conductors are installed in parallel in the same raceway, cable,
or cable tray as permitted in 310.10(H), a single equipment
grounding conductor shall be permitted. Equipment grounding
conductors installed in cable tray shall meet the minimum
requirements of 392.10(B)(1)(c).

Each equipment grounding conductor shall be sized in
compliance with 250.122.
Click to expand...
 
Since you said meter, are these service entrance conductors or feeder conductors? The SEC's require no EGC in the raceways, the feeder would require only a #1 Al in each raceway.
 
This looks like a service too me.
Here in Chicago, we are not allowed to have a main disconnect on the outside of the building. So this would not be a feeder here, because the main would be in the panel. We are also not allowed to use PVC for this type of installation, it would be IMC or RMC. There fore the panel and the meter would be bonded together by the pipe, the ground bushings and bonding jumpers.
So if you use PVC, how would the the meter box and the panel be bonded together? If you don't run a ground wire? If you need one, wouldn't it be a full size conductor in each PVC pipe?
Why would it not be sized to 250.66? That's the table we have to use for anything service related except the ground rod. The service entrance pipes are all bonded together sized to 250.66
Thanks
MIke
 
All metallic parts on the line side of the service disconnect are bonded to the service neutral. If you use PVC then you would have that connection within both the meter enclosure and within the service disconnect. You would not need to run a 5th conductor between the two as it would be in parallel with the neutral conductor. Bonding of metallic service raceways is a different requirement altogether.
 
mike1061 said:
This looks like a service too me.
Here in Chicago, we are not allowed to have a main disconnect on the outside of the building. So this would not be a feeder here, because the main would be in the panel. We are also not allowed to use PVC for this type of installation, it would be IMC or RMC. There fore the panel and the meter would be bonded together by the pipe, the ground bushings and bonding jumpers.
So if you use PVC, how would the the meter box and the panel be bonded together? If you don't run a ground wire? If you need one, wouldn't it be a full size conductor in each PVC pipe?
Why would it not be sized to 250.66? That's the table we have to use for anything service related except the ground rod. The service entrance pipes are all bonded together sized to 250.66
Thanks
MIke
Click to expand...
If you used PVC between meter and panel, the conduit definitely does not need to be bonded. Meter pans are typically bonded to the grounded [neutral] conductor simply by the lug(s) being mechanically connected to the enclosure. The panel [enclosure] is bonded by the required main bonding jumper.
 
Smart $ said:
Meter pans are typically bonded to the grounded [neutral] conductor simply by the lug(s) being mechanically connected to the enclosure.
Click to expand...

For sure, and if the enclosure was not already bonded to the neutral you would add a jumper sized per 250.66
 
iwire said:
Not allowed or just not common?
Click to expand...

Looks like not allowed.

Chicago code:

Bookmark18-27-230.70 General.
Means shall be provided to disconnect all conductors in a building or other structure from the service-entrance conductors.
(a) Location. The service disconnecting means shall be installed at a readily accessible location in the basement or first floor area of a building or structure, within the main wall, at a point not exceeding 5 ft (1.92 m) from the point of entry. When the distance of the service raceway needs to exceed 5 ft (1.92 m) from the point of entry into the building, the service raceway shall conform to the requirements of Section 18-27-230.6.
Exception: For the purposes of this section, readily accessible locations include dedicated electrical rooms, meeting the following conditions:
(1) Access to room either from inside or outside the building shall be provided for all occupants;
(2) Rooms shall have a secure, locking-type door(s) that prohibits access to persons other than tenants and/or occupants of the building.
(3) Rooms shall be of the same construction as the building;
(4) Rooms shall be for the exclusive use of the electrical service metering and distribution equipment;
(5) A panelboard with main and branch circuit protection shall be provided within the interior of each unit or space being served;
(6) A wall switch controlled lighting outlet shall be provided for illumination in all such electrical rooms.
Service disconnecting means shall not be installed in bathrooms.
In high rise buildings or similar buildings, the disconnecting means for the multiple services recognized by Section 18-27-230.2(b)(2) shall be located in a dedicated fire-rated room as near as practical to the serving utility vault. The rooms for the ?Main? service disconnecting means which serve the building common element loads shall have a three-hour fire rating. The electrical service rooms for tenant loads shall have a 2-hour minimum fire rating. These rooms shall be for the exclusive use of electrical equipment. Separate service disconnecting means shall be required for each tenant floor. These disconnects shall be permitted to be located on a floor other than the floor served. Where more than one service is permitted to serve one floor, the various disconnecting means and their locations shall be prominently identified as required by Section 18-27-230.2(e). All such rooms shall comply with Section 18-27-110.26.
(b) Marking. Each service disconnect shall be permanently marked to identify it as a service disconnect.
(c) Suitable for Use. Each service disconnecting means shall be suitable for the prevailing conditions. Service equipment installed in hazardous (classified) locations shall comply with the requirements of Articles 500 through 517.
 
jumper said:
You need a full sized EGC in each raceway in a parallel install.

300.3(B) Conductors of the Same Circuit. All conductors of
the same circuit and, where used, the grounded conductor
and all equipment grounding conductors and bonding conductors
shall be contained within the same raceway, auxiliary
gutter, cable tray, cablebus assembly, trench, cable, or
cord, unless otherwise permitted in accordance with
300.3(B)(1) through (B)(4).

(1) Paralleled Installations. Conductors shall be permitted
to be run in parallel in accordance with the provisions
of 310.10(H). The requirement to run all circuit conductors
within the same raceway, auxiliary gutter, cable tray, trench,
cable, or cord shall apply separately to each portion of the
paralleled installation, and the equipment grounding conductors
shall comply with the provisions of 250.122. Parallel runs
in cable tray shall comply with the provisions of 392.20(C).
Click to expand...

Thank-you
 
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