ABYC Definition of Ignition Protection
E11.4.15 Ignition protection - the design and construction of a device such that under design operating conditions:
a. it will not ignite a flammable hydrocarbon mixture surrounding the device when an ignition source causes an internal explosion, or
b. it is incapable of relasing sufficient electrical or thermal energy to ignite a hydrocarbon mixture, or
c. the source of ignition is hermetically sealed
What this means
If gasoline vapour is present in a space all of the electrical equipment in the space must be ignition protected to avoid causing a fire. Unless specifically labelled "Ignition Protected" all electical equipment is assumed to be capable of causing small sparks which can start a fire. Even fuses can cause a fire when they blow unless they are specifically designated as ignition protected fuses. The standard also applies to spaces with CNG or propane in specified concentrations. Ignition protected equipment is specially designed to prevent sparks either because the electrical connections are in a hermetically sealed container or because they have been designed to prevent heat transfer to the atmosphere.
To comply with the standard gasoline powered boats must have ignition protected equipment in the engine compartment, and the engine compartment must be sealed from any spaces in which non-ignition protected equipment is located. Any boats with gasoline stored below decks must have only ignition protected equipment in the area where the gasoline is stored. The storage area must be sealed from any other area where non-ignition protected equipment is located.
"Explosion Proof" is not the same as ignition protected, this more severe standard is defined in the National Electrical Code of the NFPA. Explosion proof equipment is also considered ignition protected.
Applicable Standards
Test standards include
SAE J1171, External Ignition Protection of Marine Electrical Devices and
UL 1500 , Ignition Protection test for Marine Products, and
Additional information
ABYC E.11.5.3 contains additional information on the subject including diagrams showing how compartments are to be isolated.