— In an action to recover for work, labor and services performed and materials provided, the defendant appeals from a judgment of the Supreme Court, Westchester County (Buell, J.), dated May 1, 1986, which, after a nonjury trial, is in favor of the plaintiff and against him in the principal sum of $4,049.
*679Ordered that the judgment is affirmed, with costs.
The plaintiff sustained its burden of proof in demonstrating that the electrical work performed for the defendant at his residence was for his personal benefit and not for the benefit of his wholly owned corporation. Among other matters adduced at trial was the fact that the defendant paid for part of the work with funds from his own personal checking account.
The court’s refusal to allow the defendant to testify as his own expert was correct. While interested witnesses may testify in their own behalf (CPLR 4512), the court may not only assess the credibility of such witnesses, but also their qualifications to testify as experts (Werner v Sun Oil Co., 65 NY2d 839). The defendant’s own testimony indicated his ignorance of the refinements of electrical work, and demonstrated his lack of qualifications as an expert in evaluating the cost of electrical work. Mangano, J. P., Thompson, Bracken and Weinstein, JJ., concur.