Time for a Redshiftt update. The 6-relay/receiver control box design is nearly final, so here’s a rendering from Solidworks:
Overall size is about 9 x 5 x 1 5/8″. The base is stainless steel, while the cover is transparent red vacuum-formed polycarbonate for radio transparency, plus it lets the user see the LED indicator lights inside to confirm power and the state of each relay. If the user wants to use those fuses that light up when the fuse blows, they would be visible too, for quick diagnostics without removing the cover. It has six heavy-duty automotive 30A single-pole dual-throw relays that can be individually actuated by the Redshiftt control knob and/or the free smartphone app.
By swinging the edge clasps out, the cover lifts off as above. There are 6 ATO/ATC fuse holders, and 12 paired lugs for wiring connections, six will be pre-wired as a fused circuit to the common pole of each relay. The user can then wire their own individual circuits to the normally open or normally closed pole, depending on how they want each circuit to behave. I’ve made the layout as flexible as possible and it won’t require any crimp-on connectors to bring in wire and make interconnections, wires can have the ends stripped and be inserted directly into the screw lugs on the 12-pair array and right at each relay. This makes it easy to wire each relay the way you want, since you may want power to come from different sources, and some circuits are better to have a relay switch the positive side and some circuits are best switched by grounding instead.
Wire entry is anywhere along either long side for maximum flexibility, when the cover goes back on the exiting wires are clamped between strips of foam rubber when the edge clasps draw the cover down, providing strain relief and a good seal around each wire regardless of gauge. That and embedded seals in the cover that compress against the endwalls of the metal base will make the enclosure weatherproof.
So all that’s left to do is designing some brackets to allow mounting options without increasing the footprint.