What is the test for liability in a case involving an electrical transformer failure?

"Unlike the facts of Genaust v. Illinois Power Company, supra, in the case at bar the electricity was in the process of being released or had already been released into the stream of commerce; and, in the act of doing so, defendant permitted the electricity to escape into plaintiff's residence in an unsafe form. The defendant claims that its transformer was unexpectedly defective at the time of the reinstallation. The transformer had proved not to be defective in prior use by defendant. Whether the mishap resulted from a defect in defendant's equipment that arose while in defendant's possession, or resulted from the faulty conduct of the employees during the present installation of the transformer, defendant should be subject to strict liability in tort. As a commercial supplier of a product dangerous unless safeguarded, all of the usual policy arguments dictate that defendant be held strictly liable in tort and should now bear plaintiff's burden of loss because her injuries were caused by a defect in either the power supplied, the equipment used by defendant to supply the electricity, or both."