Even the broadest commercial property form leaves a gap around machinery. The causes of loss special form excludes mechanical breakdown, artificially generated electrical current damage to electrical devices and wiring, and explosion of steam boilers, steam pipes and similar equipment that the insured owns, leases or operates.

Equipment breakdown protection, formerly called boiler and machinery insurance, fills that gap. It covers sudden breakdown of pressure, mechanical and electrical equipment, such as a boiler, a compressor, an electrical panel or production machinery.

So an owner with the special form still has a reason to buy it. Fire, by contrast, is not the reason: fire is already a covered cause of loss under the property policy.