For making safer connections (than the Quick connect terminals) to your prototype device, this quick connect terminal block has limit switches to interrupt the connection when the lid is opened. It also has a fuse for one line.

The 250V, 5A SPDT limit switches are readily available online as are the panel mount fuse holders (14mm x 1mm thread).

If you don’t want the fuse there is a fuse plug for the open spot where the fuse holder would go. 

Use one switch in each line to break connection to both incoming lines when you open the lid

The roller type limit switch is easily held down by the lid which latches shut.

The lid is held on with #6 screws as is the speaker connection terminals.

The speaker connection terminals is round but if you want to use the small rectangular shaped version then you can make a round adapter to fit into the round cavity, step files are included for you to change things.

This is a largish print but requires no supports for the base or the lid. Print lid with the top flat on the bed and fuse holder plug with threaded end up

The print is long, I printed with 0.28mm line thickness and used FF_0.28(Extra fast), Chep's super fast Cura profile to reduce print time for the base from 10Hrs to 5 ½ hours. Being low resolution the print is not very smooth but everything fits and the latch works. Lid took  ½ hrs, fuse plug took 20 minutes.

I had to smooth the start of the threads at the top of the fuse plug cavity where they didn't print but the plug went in easily with a bit of care.

Always set your (Cura) print setting “Slicing Tolerance” to “Exclusive” or the threads will be too tight and you will have to tap them or do some experimental reprinting. Even the #6 threads work when printed with this coarse settings (steel screws cut in easily).

My speaker terminals are not rated for 220V so I can't approve these for mains use, even with the fuse and limit switch, what you do yourself is at your own risk. If you are uncertain, buy a “Cliff Connector”