If it is in your bilge, it *must* be spark proof or it shouldn't be there as it's not ignition protected. This is another excerpt from ABYC:18.104.22.168.2.8. "Ignition Protected," if applicable. This shall be identified by a marking such as "SAE J1171 Marine," "UL Marine-Ignition Protected," or "Ignition Protected." The cover is not the issue... it's the receptacle... That receptacle is not ignition protected. The cover and receptacle is meant for outdoor use but not in gas fumes.