By TEBAOFLEX Jyen. Originally published on April 26, 2026.
Select from the aircraft and GPU requirements
Aircraft ground-power systems can use different AC and DC supplies. Confirm the aircraft maintenance requirements and approved ground-power-unit interface before selecting a cable assembly. Aircraft category or a familiar plug shape is not enough to establish voltage, frequency, current or pin allocation.
SAE AS 5756 addresses heavy-duty portable electrical power cable for severe flexing. A cable specification does not by itself approve the complete GPU assembly, connector, interlock or aircraft installation. Power-quality requirements and connector standards need separate confirmation.
400 Hz AC: resistance and reactance both matter
For an unchanged inductance, XL= 2πfL is eight times greater at 400 Hz than 50 Hz. The actual cable voltage drop also depends on conductor arrangement, AC resistance, load power factor, length and temperature.
Split-phase symmetrical constructions can be useful, but no universal seven-core-only rule is established here. The actual cable impedance and thermal rating must be documented. Do not infer a forbidden conductor size from skin depth alone.
DC: check starting and continuous duty separately
Illustrative assumptions: 15 m one-way length, 0.195 Ω/km resistance per pole and 500 A give ΔV= 2 × 0.015 × 0.195 × 500 = 2.925 V. At 1800 A the same assumed loop gives 10.53 V drop. From a 28.5 V source the result is 17.97 V, before connector and temperature effects. This is not evidence of a compliant engine start.
Source compensation has limits and must not create excessive voltage at light load. Include the permitted aircraft-terminal voltage, startup profile, contact resistance and heating in the approved system assessment.
Connectors and interlocks are safety-critical
A 270 V DC circuit presents a significant shock and arc hazard. Use the approved connector, interlock, protective bonding and disconnect procedure. A screened pilot conductor alone cannot guarantee safe interruption or a particular response time.
Do not repurpose or repin an AC assembly for DC in the field on the basis of aggregate conductor area. Qualification includes polarity, insulation, contact ratings, control logic and mechanical compatibility.
Procurement and acceptance
Specify continuous and transient currents, ambient conditions, handling/reeling duty, fluid exposure, connector drawing and testing obligations. Verify the completed assembly electrically and mechanically according to its approved instructions, not an unverified aircraft sizing table.
Primary references and specification evidence
The references explain the cited technology or manufacturer example. They are not TEBAOFLEX product approvals or evidence that a supplied batch has passed the tests. Request the exact product drawing, specification edition, acceptance criteria and traceable records.
Discuss your application
Discuss the duty, installation and required documentary evidence with TEBAOFLEX. WhatsApp: +86 185 9591 3361. Product suitability and test obligations must be confirmed for the specific order.