scope:

This recommended practice establishes requirements for three-conductor new round-and-flat-type oil-well cables used in supplying three-phase ac electric power to submersible pump motors. The three major cables by components are (1) cables with copper conductors, ethylene-propylene diene monomer (EPDM) insulation, nitrile jacket, and galvanized armor; (2) cables with copper conductors, EPDM insulation, EPDM jacket, and galvanized armor; and (3) cables with copper conductors, EPDM insulation, lead sheath, and galvanized armor. Cables meeting the requirements of the recommended practice should be rated for voltages not exceeding 3 kV or 5 kV (phase to phase).

Conductor temperatures for cables with nitrile jacket should not exceed 140 °C (284 ºF). Use of nitrile jacketed cable above the rated temperature can cause premature hardening of the jacket, which therefore reduces the jacket life. Conductor temperatures for cables with EPDM jacket or lead sheath may be rated up to 204 °C (400 ºF); for temperatures rated over 204 °C (400 ºF), please consult cable suppliers. Voltage ratings are nominal phase-to-phase ratings.

Cable purchased under the recommendation of this recommended practice, unless otherwise specified herein, should meet the requirements of ASTM B3, ASTM B8, ASTM B33, ASTM B189, ASTM B496, and ICEA S-68-516/NEMA WC 8, where applicable.¹

This recommended practice recognizes the common practice of continuing to operate the pump's electrical system after a phase has faulted to ground and that some power distribution systems are even designed with one corner of the delta system grounded. The purpose of this recommended practice is not to condone or disapprove of such practice, but the user should be aware that such operation produces a higher than normal phase-to-ground voltage across the insulation jacket dielectric of the two ungrounded conductors. Due to the disruption of the normally balanced three-phase field, such operation produces stresses through the insulation/jacket dielectric, which shortens cable life. ICEA S-68-516/NEMA WC 8 recommends a 173% insulation level for grounded-phase operation, but this is often impractical for downhole oil-well cable; therefore, this specifying standard recommends insulation thickness based on a normal three-phase energized delta or wye system, with no phase grounded.