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I have an old switchboard with a 16 mm2 mains cable and a 16mm2 neutral return. At a different date, someone has added another 16mm2 single main cable to the board. The two phases are feed from 2 × 63 amp fuses.

They have rewired the board to balance the two phases. I'm just asking if the neutral is capable of carrying the load of the two phases?

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  • \$\begingroup\$ does this belong on DIY.SE perhaps? it's more a question for an electrician. Also, I'm guessing by 16mm you mean 16mm²? \$\endgroup\$ – Hearth Apr 16 at 3:13
  • \$\begingroup\$ Yes 16mm squared sorry I am on my phone I have asked an electrical he said it would be fine. I could be wrong but maybe he is thinking about a 3 phase balance load. \$\endgroup\$ – Dave_oe Apr 16 at 3:19
  • \$\begingroup\$ Is this a split-phase North American power mains? (It sounds as though it may be since you say "balance the two phases.") \$\endgroup\$ – jonk Apr 16 at 3:26
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So long as the two phase conductors are tied to different phases from the power source, you are okay.

When you have a number of different loads on each phase, the Neutral conductor carries the DIFFERNCE between the two phases.

It does not matter whether the supply is a split-phase system as used in North America or any two of the phases of a 3-phase power source. The Neutral carries only the difference current.

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