I searched for "meter ring load limiter", and found this product: http://www.brooksutility.com/products/75
So the utility installs a 10-30 amp circuit breaker outside the customer's house. Should be enough to power a gas furnace, but if they draw more than 1200-7200 watts (120V*10A to 240V*30A), the breaker pops and they have to go outside and reset it.