Suppliers would have to bring in measures to detect, investigate and prevent cases.
The industry falls victim to up to 25,000 cases of electricity theft every year, costing consumers at least £200 million, or £7 per electricity customer, Ofgem said.
Up to a third of the volume of electricity stolen each year is used to power cannabis farms. Now Ofgem wants new rules to be brought in to reduce the amount of theft, with fines for suppliers who do not comply.
Under the proposals, suppliers would also have to set up a national theft risk assessment service to help them target premises where there are strong suspicions that electricity is being stolen.
Suppliers and network companies would have to create an industry code of practice governing how theft investigations should be carried out, to ensure a consistent approach across the industry. They would have to share "best practice" methods and knowledge across the industry about how cases of theft are identified, and liaise with agencies such as the police and Home Office over how to tackle electricity theft relating to cannabis farms, Ofgem suggested.
Andrew Wright, Ofgem's chief executive, said: "Ofgem wants to make sure that consumers are paying no more than they need to for their electricity, and lives are not put at risk. It's critical that suppliers do all they can to clamp down on electricity theft. This is why Ofgem is introducing new rules to encourage better theft detection.
"The reforms build on similar obligations we introduced at the start of this year for suppliers to address gas theft more vigorously. All these measures will help to improve the confidence of consumers, who want reassurance that the energy market is fair."
Energy UK, the trade association of the energy industry which represents more than 80 companies, welcomed the proposals. A spokesman said: "Ofgem's consultation is a positive move to cut down crime, and we look forward to working closely with them, and others in the industry, on this."
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