Ignition apparatus having an electrically floating shield with integrated boot and seal

An ignition apparatus (10) includes a magnetic circuit comprising a central core (16) and a side core or shield (36), and primary (24) and secondary (30) windings. The shield (36) is allowed to electrically float, thereby reducing the capacitance of the secondary winding (30). A unitary boot (38) surrounds the shield (36) to inhibit arcing, and further includes a seal (46) configured to seal a spark plug well (11) or the like.