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View Full Version : Sec cable sizing


rams05
Sep 8, 2011, 08:54 PM
I am upgrading from a 100 to 200 amp service and will be upgrading my sec cable to a 2/0 or 3/0 thhn. Ive been told that nec permits downsizing of the neutral wire. Is this true and if so what size is acceptable?

tkrussell
Sep 9, 2011, 02:37 AM
If calculated, the neutral can be no smaller than 70% of the rating of the circuit.

For the live conductors, #2/0 copper and # 4/0 aluminum is allowed for 200 Amp.

SEC Cable has a full size neutral.