High Intensity Discharge Lamps
HID lamps run parking lots, wall packs, gyms and warehouses. The lamp must match the ballast: metal halide, high pressure sodium and mercury vapor lamps are not interchangeable, and pulse start metal halide needs a pulse start ballast. Read the ANSI code on the old lamp or ballast label and match wattage and base (E26 medium or E39 mogul). Replacing the whole fixture soon? An LED corn cob lamp is often the cheaper middle step.
