277/480V 3 Phase 4W

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mstrlucky74

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Would the feed to this distribution panel contain a neutral and/or ground. I know it says 4W( does no say + GND) so to me that's 3 phase conductors and a neutral but no ground needed(use emt). Do you agree? Thanks.
 
Jraef

Jraef

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I suggest you read this previous thread.

http://forums.mikeholt.com/showthread.php?t=142364

Just FYI also. When you see a CIRCUIT described by the number of wires, i.e. 3W or 4W, that is always referring to the number of Current carrying Conductors (CCC), and a Neutral is always considered a CCC. Ground is not, because the NEC assumes a EGC is always part of the picture, despite how you get there. When you see something that says "3 wire + G" or "4W w/G", that is a description used only by the manufacturer of a multi-conductor CABLE, i.e. Romex or SO cord. It has no official definition in the NEC (that I am aware of).
 
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mstrlucky74

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Jraef said:
I suggest you read this previous thread.

http://forums.mikeholt.com/showthread.php?t=142364

Just FYI also. When you see a CIRCUIT described by the number of wires, i.e. 3W or 4W, that is always referring to the number of Current carrying Conductors (CCC), and a Neutral is always considered a CCC. Ground is not, because the NEC assumes a EGC is always part of the picture, despite how you get there. When you see something that says "3 wire + G" or "4W w/G", that is a description used only by the manufacturer of a multi-conductor CABLE, i.e. Romex or SO cord. It has no official definition in the NEC (that I am aware of).
Click to expand...

Thanks.
 
infinity

infinity

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mstrlucky74 said:
Would the feed to this distribution panel contain a neutral and/or ground. I know it says 4W( does no say + GND) so to me that's 3 phase conductors and a neutral but no ground needed(use emt). Do you agree? Thanks.
Click to expand...

Always assume that there is an EGC the distinction is whether it's a metallic conduit, a separate conductor or both.
 
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mstrlucky74

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Ok dumb question. going from 277/480v panel to 277/480v panel. What voltage would you enter and why...277 or 480? It's a voltage drop calculator.
Wire Material
Copper Aluminum Silver Gold
Wire Size
600 kcmil 500 kcmil 400 kcmil 350 kcmil 300 kcmil 250 kcmil 4/0 AWG (212 kcmil) 3/0 AWG (168 kcmil) 2/0 AWG (133 kcmil) 1/0 AWG (106 kcmil) 1 AWG (83.7 kcmil) 2 AWG (66.4 kcmil) 3 AWG (52.6 kcmil) 4 AWG (41.7 kcmil) 5 AWG (33.1 kcmil) 6 AWG (26.3 kcmil) 7 AWG (20.8 kcmil) 8 AWG (16.5 kcmil) 9 AWG (13.1 kcmil) 10 AWG (10.4 kcmil) 11 AWG (8.23 kcmil) 12 AWG (6.53 kcmil) 13 AWG (5.18 kcmil) 14 AWG (4.11 kcmil) 15 AWG (3.26 kcmil) 16 AWG (2.58 kcmil) 17 AWG (2.05 kcmil) 18 AWG (1.62 kcmil) 19 AWG (1.29 kcmil) 20 AWG (1.02 kcmil) 21 AWG (0.810 kcmil) 22 AWG (0.642 kcmil) 23 AWG (0.509 kcmil) 24 AWG (0.404 kcmil) 25 AWG (0.320 kcmil) 26 AWG (0.254 kcmil) 27 AWG (0.202 kcmil) 28 AWG (0.160 kcmil) 29 AWG (0.127 kcmil) 30 AWG (0.101 kcmil) 31 AWG (0.0797 kcmil) 32 AWG (0.0632 kcmil) 33 AWG (0.0501 kcmil) 34 AWG (0.0398 kcmil) 35 AWG (0.0315 kcmil) 36 AWG (0.0250 kcmil) 37 AWG (0.0198 kcmil) 38 AWG (0.0157 kcmil) 39 AWG (0.0125 kcmil) 40 AWG (0.00989 kcmil)
Voltage
Distance*
 feet meters miles kilometers
Load current
 Amps
 
infinity

infinity

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480 volts since it's a 480 volt feeder. It should be noted as 480Y/277 volts if it's 3Ø.
 
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GoldDigger

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That voltage drop calculator is probably going to use the value that you entered for the percentage voltage drop calculation, since the absolute voltage drop depends only on the current, not the voltage.
 
Jraef

Jraef

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mstrlucky74 said:
Yes it says 277/480v..in that order.
Click to expand...
Actually that's just a mistake, a very common one too. OFFICIALLY, 3 phase voltages should always be denoted as the higher number first, the lower second. So 480/277 is correct, 277/480 is not; 208/120 is correct, 120/208 is not. But in the case of 480/277, we always know what it means, there is no alternate interpretation. Where it can get confusing is in 240V, because if you say "120/240V" it officially means it is a SINGLE PHASE system, whereas "240/120V" would officially denote a 3 phase 4 wire delta center tapped system (although because the error is so common, it's best to just say "240/120 3 phase 4 wire").

Side note: I thought it interesting that the calculator refers to gold conductors. Can you imagine seeing 500kCMIL gold cable? I can, but not for long!
 
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mstrlucky74

Senior Member
Location
NJ
Jraef said:
Actually that's just a mistake, a very common one too. OFFICIALLY, 3 phase voltages should always be denoted as the higher number first, the lower second. So 480/277 is correct, 277/480 is not; 208/120 is correct, 120/208 is not. But in the case of 480/277, we always know what it means, there is no alternate interpretation. Where it can get confusing is in 240V, because if you say "120/240V" it officially means it is a SINGLE PHASE system, whereas "240/120V" would officially denote a 3 phase 4 wire delta center tapped system (although because the error is so common, it's best to just say "240/120 3 phase 4 wire").

Side note: I thought it interesting that the calculator refers to gold conductors. Can you imagine seeing 500kCMIL gold cable? I can, but not for long!
Click to expand...


lol...not for long is right.
 
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