Debate came up about downsizing a neutral. Was going to run #10s after doing a voltage drop calculation, boss said run #12 for neutral. To my knowledge the neutral is counted in the calculation.
4-024 Size of neutral conductor (see Appendix B)
(1) The neutral conductor shall have sufficient ampacity to carry the unbalanced load.
(2) The maximum unbalanced load shall be the maximum connected load between the neutral and any one
ungrounded conductor as determined by Section 8 but subject to the following:
(a) there shall be no reduction in the size of the neutral for that portion of the load that consists of
(i) electric-discharge lighting; or
(ii) non-linear loads supplied froma 3-phase, 4-wire system; and
(b) except as required otherwise by Item (a), a demand factor of 70% shall bepermitted to be applied
to that portion of the unbalanced load in excess of 200 A.
If the circuit OCD is 20-amps and the load is 9, why couldn't you install a 20-amp rated neutral? (US install, I think the OP is Canadian and I think VD calculations are mandatory there where recommended here).No! Can't reduce that size wire.
If your code restricts you to a 3% or less VD, you will need to install #8 conductors.Debate came up about downsizing a neutral. Was going to run #10s after doing a voltage drop calculation, boss said run #12 for neutral. To my knowledge the neutral is counted in the calculation.
Even if you have 20-amp overcurrent protection?It means that you can start to derate the neutral after the 200A mark, and then only 70% of it.
So no, you can't run a #12 neutral with #10 hots.
Feeding Unit Heaters, 120v, 220ft, 9Amps, multiple CCTs sharing the neutral on a 3 phase system
We have tables in our code up here for voltage drop. I'm wondering if in those calculations for table D3 they've included the return path. We're supposed to enter in the distance from the panel to the load into the formula, but in that formula have they calculated the return path? I guess I'm searching for two answers. Can I do it code wise? The answer is no because its a non-linear (unbalanced load).CADPoint said:Scared to post because it's a the great white north thread.
In the end the physic's don't lie.
For #12 about 120'
For #10 about 180'
For #8 about 230'
Before one has to remember VD if appliable.
I don't know what to say it's Canada! Eh!
No resistive heat is linear, nonlinear would be any types of electronic loadsI'm in Canada yes
Basically where it says in the code 'non linear' is what I'm going by. So if everything was perfectly balanced then the 3 phase set (RED, BLACK, BLUE and WHITE) would have nothing on the neutral returning. Since we'll never know when and if certain phases will be turned on its non linear. 4-024 (2) (a) (ii)
hardworkingstiff said:I guess I have a different understanding of a linear load than you. I was of the impression that resistance heaters (I think that's what is being wired) are always linear loads.
Good point. These are gas unit heaters in a large warehouse, they do have small motors in them to dissipate the heat outwards. I was thinking its none linear but its not (not non-linear? Lol) Thanks now I'm back to square one.brian john said:No resistive heat is linear, nonlinear would be any types of electronic loads
I'm of the understanding that motors are non linear loads. So the motors in the gas heaters would be non linear. :laughing:Good point. These are gas unit heaters in a large warehouse, they do have small motors in them to dissipate the heat outwards. I was thinking its none linear but its not (not non-linear? Lol) Thanks now I'm back to square one.