Section 119A. When a consumer is charged for gas or electricity at several rates according to the quantity used, his bill, to the extent that the gas or electricity is used for domestic purposes, shall be so itemized as to show the quantity charged for at each rate, and where the use is for other than domestic purposes such detail shall be furnished by the company on request of the consumer, and the bill shall contain a statement to this effect. All fuel charges imposed by electric companies pursuant to section ninety-four G shall be itemized separately on all bills to customers.