The Wooden Camera DBox has, as most well made power distribution boxes, a fuse protected backbone connector plate, taking the 12-18VDC inout from the 4-pin Mini Power connector, and distributes it to the various output ports connected. For regulated, WC incorporates a voltage regulation board attached behind the connector, and shrink wrapped in place.
Ground isolation, when used, is provided by the use of diodes, which only allow pieermto flow in one direction, preventing a back flow of power, that would occur if the ground and hot got shorted, or someone switched hot sand ground on a connected cable. This prevents attached gear from getting fried by the short. I have not seen a WC DBox backbone, so not sure how they are doing it. I do know it is fuse protected.
The original BDS power distribution box has isolated ground and power regulated outputs, which is why it started at $600 to $1200. The concept goes back to when high amp bsttereis were being used to power multi-equipment setups, requiring 24-VDC and 12-VDC in the field, so big car battery type banks were used, connected to the BDS with large cables, and Lemo connections onmthe BDS carried the power to individual pices of equipment, mostly audio back then. Then boxes were made to take the big video camera battery bricks, the size got smaller, and the rest is history...
A WC DBox starter kit is about $200 and comes with the backbone, a 4-pin XLR input, and angled 4-pin Mini to DTap cable to connect the box to a battery plate with a DTap connection, like the Gold mount or V Mount plates which screw to the top of the DBox. You then add the connectors of choice, for outputs.
I put together a basic DBox with Inez DTap and one 2-pin Lemo, and the cost came to $419. However, for $449 you can get a ready made DBox from WC with two DTap, 2-Lemo (12-VDC 2-pin) and one HDMI 5-VDC out for $449.00, which would be the way to go, for $30 more you get the additional connections, a no brainer in my book.
Cheers