Do you have the electric hooked up and grounded to the 3rd prong on your plug? Using the 3rd ground prong is a lot safer with or without a GFCI outlet. Plus to work correctly the GFCI outlet has to be wired correctly (my hubby is a part-time contractor and has seen GFCI outlets in a house, and they're not even hooked up right, so they would offer no protection!!) Not criticizing you, just want to make sure you're being safe!!
You can also use "piano hinges" for the lid, they are a little longer and prettier, and just as strong