The higher the voltage, the more insulation required to prevent a fault.
You have a fire waiting to happen. To use the 600W lights in a 28 gauge wire you are going to need ~480V. Depending on the brand, the HDPE insulation in a CAT5 cable is ~0.007" thick. It will withstand that voltage, only for a while. It will breakdown and fault. Maybe it will last a few months, maybe a few years, depending on how often and for how long you use it. If it is lower voltage than that, you are sending more than 1.25 amps down a 28 gauge wire and it is building more heat that the HDPE will withstand over time.
Quit using that piece of crap installation. If you cannot wire it yourself, hire someone that isn't willing to cause a fire.
Quit using that piece of crap installation. If you cannot wire it yourself, hire someone that isn’t willing to cause a fire.
I’m with you on the insulation. In my early 20’s I put some Cibia pencil beam lights on my Opel GT and wired it with speaker wire. After a few miles the lights went out and when I opened the hood, I saw the insulation was melted and the wires were grounding out. I’m very “sensitive” about insulation and heat. But the guy IS an electrician and DID use math to support his wiring. I’m not particularly concerned because I don’t think these lights will ever see any serious use - if any at all. :-)
For the record, Cat5 uses 24-26ga. conductors. Was he using one conductor per bulb? That's what the original comment sounded like to me.