Can I use network cable for low voltage DC power?
Modular Jacks are rated for 1.5A per pin including surge current to charge caps with hot insertion.

There are many varieties of modular jacks and cables or crimp plugs so you can gang contacts.  It is best for the longevity of "flash" ( u" thin) gold plating, that prevents rust, to avoid hot insertion ( live DC power) of the plug, rather make connections then turn on supply.

Examples of Jacks