Yoop:
As I understand your question, IMHO, as long as the AWG of the 'static line' is compliant with the OCP, I see no reasoning why you can't use it. It is NOT a neutral.
Text from what I believe is the relevant Article (2011)
"250.186 Impedance Grounded Neutral Systems. Impedance
grounded neutral systems in which a grounding impedance,
usually a resistor, limits the ground-fault current
shall be permitted where all of the following conditions are
met:
(1) The conditions of maintenance and supervision ensure
that only qualified persons service the installation.
(2) Ground detectors are installed on the system.
(3) Line-to-neutral loads are not served.
Impedance grounded neutral systems shall comply with
the provisions of 250.186(A) through (D).
(A) Location. The grounding impedance shall be inserted
in the grounding electrode conductor between the grounding
electrode of the supply system and the neutral point of
the supply transformer or generator.
(B) Identified and Insulated. The neutral conductor of an
impedance grounded neutral system shall be identified, as
well as fully insulated with the same insulation as the phase
conductors.
(C) System Neutral Conductor Connection. The system
neutral conductor shall not be connected to ground, except
through the neutral grounding impedance.
(D) Equipment Grounding Conductors. Equipment
grounding conductors shall be permitted to be bare and
shall be electrically connected to the ground bus and
grounding electrode conductor.
