richms: Perhaps that's just down there, but in Auckland there is no problem having an install without one, never seen one installed in a business or apartment install either.
Surprising. From Vector's FAQ
"Is it possible to be excluded from having the hot water heating turned off?
Customers can choose a price plan where Vector does not control their hot water however these Customers pay a higher price for line charges than those who allow control of hot water.
There may be additional costs to have any existing load management devices disabled or removed when moving from a controlled pricing plan to an uncontrolled pricing plan. This is arranged through the electricity retailer."
Also interesting (to me anyway) is that pilot wires rather than ripple control is used on the North Shore, in Waitakere, and parts of Rodney.