National Electrical Installation Standards

Standards as High as Your Own

Tuesday, December 5, 2017


NEC 300.14 clarification - ac conductors enter Fronius snapINverters and terminate on terminal blocks. Do the conductors coming into the inverter need to be 6 inches long? I believe the inverter is a device and 300.14 applies but I am being told that ac wiring inside the inverter does not apply.

William Burkert



Hey William thanks for your question. Section 300.14 applies to outlet, junction and switch points and requires 6 inches of free conductors. Conductors that are in integral part of equipment do not need to comply with that rule as stated in 300.1(B). Usually the manufacturer's instructions will provide sufficient detail for conductor terminations especially part of listed equipment. Inverters for use with PV systems must be listed as stated in 690.4(B). If the termination point of the field installed conductors in the inverter is considered an outlet as defined in Article 100 then the 6 inch minimum dimension applies. Even if it does not apply, providing sufficient conductor length for future servicing and maintenance is a good idea.

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