Trying to work through a service set up for a small industrial building. I have what appears to be a 480v corner grounded feed from the POCO. This feed hits a 480v 400amp disco,disco feeds a 480v /208/120 225kva x-former. Two feeds from this transformer hit at differant ends of the building. The remodel project includes approx ten new motor loads with a aproxamite current draw of 165 amps at 480v three phase. A new 480v service will be built and I have a couple of questions on the setup. I plan on using a fused disconnect bringing in the two phase conductors and the grounded conductor. The two phase conductors will land on the line side of fused lugs. The grounded conductor will land on a bar that is bonded to the can, from this bar a #6 will go to 2 driven ground rods. May I then bring a conductor from this bar to a switched solid neutral in the disconnect? I will then bring 4 conductors to the building (1) equipment ground (1) grounded conductor (2) phase conductors. I would like to terminate in the new building in a 225 Main Breaker 480v panelboard. The equipment grounding conductor lands on a grounding bar, the (2) phases land on the main breaker does the grounded conductor also land in the main breaker? This will be a new set up for me and any help or comment will be appreciated.
480v corner grounded
- Thread starter eds
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Your plan seems to be correct. Don't forget your other grounding electrodes (building steel, etc)
On a 480 Delta, Corner Grounded System the grounded conductor may have overcurrent device if that overcurrent device opens all the conductors, so you may use 3 pole breakers. That may be an advantage from an availability standpoint.
When used as motor overload protection, the grounded conductor must also have overload protection
On a 480 Delta, Corner Grounded System the grounded conductor may have overcurrent device if that overcurrent device opens all the conductors, so you may use 3 pole breakers. That may be an advantage from an availability standpoint.
When used as motor overload protection, the grounded conductor must also have overload protection
will the grounded conductor always be marked as such, when I land it on the Main breaker it will be marked gray, when I bring it to my three phase motors will it also be marked as gray? I will need to review my building steel guidlines. The initial service disconnect will be located about 50 yards away in a field.
I have another question, as I am still in the think it out stage. The service disconnect is located away from the building, would I be able to bring the feeders up into a MCC? Bringing the feeder up into the building will require a disconnect since there is more than six throws, are there MCC with a main disconnect? Thanks for the responses, we don't see much of these configurations
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