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Friday, June 12, 2020
Question:
Greetings,
I have a 400-amp service to a house with 2 200-amp breakers for disconnects. The 2 200-amp sub panels are in the interior of the house with a concrete slab floor. Does the sub panel feeder have to be in conduit or just buried 18 inches using direct burial service feeders?
Ted Stripling
A
Answer:
Hello Ted,
Thanks for the question. Based on the information provided, the feeders from the service equipment to the panelboards (sub panels) inside the home, should be installed using a suitable direct burial wiring method (Direct burial rated MC Cable) in accordance with Exception No. 2 to Section 300.5(C) and 330.10(A)(5). It is important to remember the general rule here in 300.5(C) is to installed conductors and cable in raceways under buildings. From a practical and workmanship standpoint, conductors or cable in a raceway allows accessibility for reworking them or repairs and so forth that may be necessary later. With a direct buried cable, if something were to go wrong, it would likely need to be abandoned and a new feeder rerouted overhead. Just thoughts based on your question. Hope this is useful.