Table 6 SOUTH WALES: CONSOLIDATION OF ELECTRICITY SUPPLY BEFORE 1948.
| UNDERTAKING | YEARS IN OPERATION | NEW OWNER |
| Briton Ferry UD | 1910?-1922 | Neath MB |
| Llandilo UD | 1902-1933 | West Cambrian Power |
| Tenby Gas Co. | 1928-1933 | West Cambrian Power |
| Brecon MB | 1928-1935 | S W S Co. |
| Glantawe Co. | 1910-1936 | South Wales Power |
| Brynammon Co. | 1915-1938 | South Wales Power |
| Ogmore Valley E L & P Co. | 1892-1943 | Ogmore & Garw UD |
| Municipal Takeover of Company Undertakings | ||
| Cardiff RD | 1923 (Radyr Co.) | |
| Llandrindod Wells UD | 1923 | |
| Ammanford UD | 1924 | |
| Penarth UD | 1938 | |
