MIL-HDBK-274 Electrical Grounding For Aircraft SafetyThis handbook has been prepared to provide U.S. Navy and Marine Corps aircraft maintenance and operations personnel with the background and technical details of the different types of aircraft grounds and how they are applied. In addition, this handbook provides background information for aircraft grounding, static electricity theory and how it affects aircraft, and techniques used for measurement of grounding points. This handbook is intended for use by all U.S. Navy and Marine Corps aircraft maintenance and operations personnel for the purposes of ensuring that aircraft are properly and safely grounded. This handbook is for guidance only and cannot be cited as a requirement.

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MIL-HDBK-274A

FIGURE 19.  Grounding cable with clamps.

FIGURE 20.  Grounding cable with clamp and plug.

5.14.1 Ground cable construction. Ground cable construction: cables should be of "7 x 7" construction, 2.38mm (0.094 inch) nominal diameter wire rope with MIL-DTL-83413 clamps at each end.  In accordance with OP 5, all grounding cables should have clamp-to-clamp or clamp- to-structure resistance less than or equal to the design specification or less than 1 ohm if no design specification is given.  Flight line reel type cables (see Figure 21) are required to have 25 ohms or less resistance.  Cable length should be determined by user operational requirements but cable DC resistance should not exceed 25 ohms.  The cables should be marked as an "ordnance grounding cable" and serialized.  IAW OP 4 and OP 5 Volume I, Paragraph 5-9.7.3: "All grounding cables shall have a visual inspection and electrical test after procurement or fabrication, prior to being placed in service.  Thereafter, a visual inspection and electrical test shall be performed on every repaired cable before the cable is placed back in service.  Proof of the last electrical test must be provided for each grounding cable in use."

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