Custom-made 4-pin XLR breakout box and long cable
Here are two custom-made pieces of gear using 4-pin XLR connectors, with pins 1 and 4 wired, the standard for power applications. But of course you can use them for anything else that requires 4-pin connections.
I made these myself a while back when gathering equipment for my field kit. There was nothing on the commercial market like them.
First is a 3-way power tap, or breakout box if you like. Plug the male cable end into a battery or power supply and you have three female connectors, each with juice for whatever loads you need to power.
I found small cast aluminum boxes, and had a machine shop cut out three holes for the Neutrik female panel connectors The pigtail has a Neutrik 4-pin male connector. This is very well made (actual, unretouched photos here) and was used only occasionally, and is still in excellent condition; I checked it for continuity and shorts. Asking price is $75.
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Next is a heavy-duty 30-cable, with male and female Neutrik connectors at the ends. Like the breakout box, I built this myself since there was nothing similar on the market.
I used Whirlwind 14/2 speaker cable, which is a heavy enough gauge to carry DC with little voltage drop over the 30 feet. A RIP-TIE velcro strap is attached.
This cable was used only a few times, mostly to power a large camera which was mounted on a small jib. An AC power supply sent DC voltage over the cable to the camera which was easier to move with the jib with since we didn't need a heavy brick on the camera back. You can use it for similar situations where you want to remotely power the gear.
The cable, like the box, is in excellent condition and also checked for continuity and shorts. Asking price for the 30-ft. cable is $65. You can have both the box and cable for $130.
If you're in the NYC area, you can inspect these pieces, and take, cash-and-carry, from my UWS location (I'm a few blocks from 96th/B'way). Otherwise, I can ship for additional charges and a PayPal prepayment (the breakout box itself should easily fit into a small Priority box).