S-cord Portable Cable Chart
| Letter | Letter Designation |
| S | Service (or Hard Service Cord) (600 Volts) |
| SJ | Junior Service Cord (300 Volts) |
| E | (Elastomer) Thermoplastic Rubber |
| T | Thermoplastic |
| O | Oil resistant outer jacket |
| OO | Oil resistant insulation and outer jacket |
| W | Approved for outdoor use. Weather and Water Resistant |