Why do I have to keep my supply topped up if I'm not using any energy?

Even though you might not be using any energy, there's a daily standing charge. Also, any debt you might be repaying through your meter will continue to be charged. So if you're away from home or not using any energy for a period of time, please make sure there's enough credit in the meter to prevent the supply from going off. If not, any appliances that need continuous supply, such as your fridge or freezer, might be at risk.