The Supply Number   What is a supply number? A supply number, also referred to as "S" number, is a unique reference which identifies the electricity meter at your property. The Supply number contains information (i.e. meter type) required by your new supplier. Where can I find my supply number? The supply number appears on your bill. In almost all cases each household will have only one supply number per meter. What does a supply number look like? The standard format for an electricity supply number is:  S 03 456 789 19 0123 4567 890 The top line of the supply number contains information about whether you are a domestic or business consumer, and which tariff you are on. It will therefore change as you change your supply details. The bottom line of the supply number contains information about the local electricity distribution company responsible for maintaining the cables and wires carrying electricity into your home, plus a unique reference number to identify the meter in your property. The bottom line of information will not change when you switch supplier.