From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Specification for 600 Megohm Grade, Metal Braided, Twin Core Electric Cable.
| Identifier | ExFiles\Box 168b\2\ img078 | |
| Date | 27th September 1922 | |
| ROLLS ROYCE LIMITED. MATERIAL. Electric Cable. 600 Megohm Grade. SPECIFICATION NUMBER. 253. Metal Braided. TYPE OF CORE. Twin. CORE SIZE. 2 - 40/36. OUTSIDE DIAMETER. .375" CONDUCTOR. High Conductivity Tinned Copper Wire DIELECTRIC. One layer pure and two layers vulcanising rubber. Both to be equal in quality to First Grade Plantation Rubber. The Vulcanizing Rubber shall contain at least 40% Pure Rubber. Mineral fillers only shall be used. Proportion by weight of sulphur shall not exceed 2.5%. PROTECTIVE COVERING. Both cores to be taped. One coloured red and the other white. Cores twisted together and wormed circular with cotton. Taped and protected overall with a Braid of 36 SWG. Tinned Copper wire. | ||