On a recent project a motor starter panel required 250A 480V feeder, so I installed 2" IMC with 3 250MCM copper conductors and a #4 copper ground wire, now thw owner wants to increase the feeder to 400A to pickup some additional loads being installed, my intension is to run another 2" IMC and parrell 3 more 250MCM copper conductors, but the #4 copper ground wire installed in the first conduit is to small for 400A according to table 250.122. The conduits are about 300 feet long may be able to pull the #4 out and pull in a larger EGC conductor if it is necessary or can use the conduit as the ground? Or what other options are there?
EGC Size question
- Thread starter hochwire
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Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
Options:
1. pull out the existing 4 AWG and install the 3 AWG in each raceway as per 250122(F
2. pull out the existing 4 AWG and use the raceways as your EGC.
3. Abandon the original 4 AWG EGC (make sure to safe it off - tape, wirenuts, etc... and I would tag it as abandoned), and use the raceways as your EGC.
1. pull out the existing 4 AWG and install the 3 AWG in each raceway as per 250122(F
2. pull out the existing 4 AWG and use the raceways as your EGC.
3. Abandon the original 4 AWG EGC (make sure to safe it off - tape, wirenuts, etc... and I would tag it as abandoned), and use the raceways as your EGC.
ivsenroute
Senior Member
- Location
- Florida
Is the addition of the 3awg going to put you into another conduit size depending on the insulation type?
ivsenroute
Senior Member
- Location
- Florida
What wire are you using for the egc and conductors?
ivsenroute
Senior Member
- Location
- Florida
With that you are only at 1.288 (3 250's and one 3awg) so you are way good.
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