Coil heaters and cable heaters are heating elements formed from straight, uncoiled segments of heating cable. Forming straight cables into patterns increases the surface area and heat transfer capability, but also requires increased energy and watt density. Most coil heaters and cable heaters operate on AC voltages. Some include a grounding wire or provide distributed wattage arrangements to concentrate heat distribution. Coil heaters and cable heaters can be configured with different termination options. For example, electrical connections can be made via a plug configuration and protected by a terminal box interface. Armor cable, metal braids, and flexible conduits are used to protect insulated leads.