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).
Material specification for single core electric cable.
| Identifier | ExFiles\Box 168b\2\ img084 | |
| Date | 13th October 1922 guessed | |
| COPY. No. 1656. For use of Works Supt. ROLLS ROYCE LIMITED MATERIAL Electric Cable. SPECIFICATION NUMBER 261. TYPE OF CORE Single CORE SIZE 70/36 O/S DIA+ Maximum. .187" CONDUCTOR High Conductivity Tinned Copper Wire DIELECTRIC One layer Pure rubber - one layer white vulcanizing rubber and one layer black vulcanizing rubber. Total radial thickness of whole .035". Rubber shall be equal in quality to First Quality Plantation Rubber. 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 One layer of impregnated cotton braiding coloured either red, black, or Red & Black speckled, as specified on our orders. | ||