nuetral current
- Thread starter kimrichi
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jumper
Senior Member
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Which example?
I don't see a dishwasher mentioned in the example (or the referenced example)...???
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
I believe the example under discussion is D1(b). It adds three 115-120 volt appliances: 12 amp A/C unit, 10 amp dishwasher, and 8 amp disposal. The presumption is that not all three will go on the same phase. They placed the largest two on Phase A and Phase B, so that the neutral imbalance (i.e., if one was running and the other was not) would be the higher of the two ratings. In other words, if the 12 amp A/C unit (on Phase A) is running, and the 10 amp dishwasher (on Phase B) is not running, then the neutral will have 12 amps of current. It is not necessary to add the 10 amps of neutral current that the dishwasher might contribute if it was running, since it would oppose the neutral current from the A/C unit, and the result of the two neutral currents will be smaller than either one alone. So they count the neutral contribution at 12 amps, the highest possible neutral current being contributed from those two appliances. It does say that in the example text, just above the table of current values.
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