315,411. Koch & Sterzel Akt.-Ges. July 14, 1928, [Convention date]. Transformers.-The insulating container for a transformer is extended around its primary terminal sections to act as a shield. As shown in Figs. 2 and 3, the insulating container 11 is formed with a transverse hole 12 through which passes the centre limb 16 of the laminated core surrounded by the secondary winding 15. The primary winding 14 is wound around the walls 13 of the transverse aperture, its ends 17, 18 being clamped at 19, 20 to socket contacts 30, 31 mounted on plates 23 separated by an insulating partition 27. The sockets 30, 31 may co-operate with plugs 32, 33 passing downwardly through an insulating sleeve 34, the transformer casing 11 being extended around the contact sockets so that a long sinuous breakdown path extends between the primary terminals and the earthed enclosing shield 35. The latter has secured to it a metal protective casing 28 secured around the transformer and provided with handles 39, the casing 28 also carrying the secondary terminals 21, 22. The transformer may have merely screw-down terminals 19, 20 as shown in Fig. 1, which are screened by the extension 29 of the insulating casing 11. The terminals are mounted on insulating plates 23, 24 held in position by an inner ridge 25 of the insulating casing 11. In an alternative form the terminals may be brought out at opposite ends of the casing 11. A transformer of this type may be employed in draw-out switchgear as shown in Fig. 5, in which the transformer forms part of one of the isolating contacts 46, the insulating casing being extended around it at 51. The transformer with its casing may similarly be formed as a bus-bar coupler (Fig. 6, not shown).