using half of the transformer's winding

[emj12]

Hello, I am using a 25v C.T. transformer for a heater supply, although I am only using one hot lead and the C.T. going into a brigde rectifier as that will give me 12v.

The other hot lead is capped. My question is whether I should leave that lead capped or ground it?

[amptramp]

Insulate the lead.  It should not contact anything.