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whproject
Theoretically speaking If I have a 3 phase 4 wire supply L1 L2 L3 and N
[FONT=verdana, arial, helvetica]And the 3 hot phases are 120 degrees offset, bar any faults and line harmonics etc, the max load on the common (shared) N, would be that of the heaviest load on a single phase right , EG[/FONT]
[FONT=verdana, arial, helvetica]L1 draws 63a L2 draws 69a and L3 draws 72a (at the same time), the load on the common N, would be 72a right, provided of coarse my 3 live phases are offset by 120 degrees.[/FONT]
[FONT=verdana, arial, helvetica]Take this hypothetical scenario, I am using 100a rated wire for the live phases, I want to use the same 100a cable for the common N, problem is, I understand [/FONT]HID[FONT=verdana, arial, helvetica] light ballast can create harmonics.
Does this mean the phases degree offset can slightly fluctuate , if so, would it be a dangerous problem when using the amperages mentioned above, to overload a common N, I hear harmonics can cause 150% of the hot load load to return through the N, would the theory be right to think that this would still only mean 150% of 72 amps, (the heaviest load on any hot phase), thus deeming the 100 amp rated wire for the common N not ideal but theoretically safe?
Thanks for your time, [/FONT]
[FONT=verdana, arial, helvetica]And the 3 hot phases are 120 degrees offset, bar any faults and line harmonics etc, the max load on the common (shared) N, would be that of the heaviest load on a single phase right , EG[/FONT]
[FONT=verdana, arial, helvetica]L1 draws 63a L2 draws 69a and L3 draws 72a (at the same time), the load on the common N, would be 72a right, provided of coarse my 3 live phases are offset by 120 degrees.[/FONT]
[FONT=verdana, arial, helvetica]Take this hypothetical scenario, I am using 100a rated wire for the live phases, I want to use the same 100a cable for the common N, problem is, I understand [/FONT]HID[FONT=verdana, arial, helvetica] light ballast can create harmonics.
Does this mean the phases degree offset can slightly fluctuate , if so, would it be a dangerous problem when using the amperages mentioned above, to overload a common N, I hear harmonics can cause 150% of the hot load load to return through the N, would the theory be right to think that this would still only mean 150% of 72 amps, (the heaviest load on any hot phase), thus deeming the 100 amp rated wire for the common N not ideal but theoretically safe?
Thanks for your time, [/FONT]