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I have an inverter for cold cathode lights powered via a molex connector from a PC power supply, with a PCI/PCI-E slot bracket where is placed an ON/OFF switch, and I would need to use one light at a longer distance, exactly at a distance of 7 and half metres. There is a 2-pin connector leading to the inverter. From what I have read, cables leading to a cold cathode from the inverter hasn't to be long, so it seems like that the only option is by using a 2-pin extension cable. Can it be used like this and if yes, what wire I need to use for it? Assuming there isn't such extension available to purchase, can I cut the cable and solder the wires to create an extension?

Some more information:

Input voltage of the inverter: 12 V

Output voltage of the inverter: 680 V

Current draw: 5 mA

Lubomír
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  • You're right that you should extend the 12 V side, not the 680 V. What kind of connector does the inverter use on it's input? What's the current wire gauge for the 12 V side? Does the inverter have specs for minimum input voltage? What's the measured output voltage for the PSU's 12 V you're using? – RaphaelP Jan 24 '20 at 14:15
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    Also, when you say the current draw is 5 mA, where's that measured? 12 V going into the inverter? 680 V coming out of it? 120/240 V into the PSU? – RaphaelP Jan 24 '20 at 14:19
  • It's a small 2-pin connector. Gauge of the wire is 20 AWG. The inverter doesn't have a specs for minimum input voltage. The measured output voltage of the 12 V rail is 12.146 V on average, according to HWiNFO. The current draw 5 mA is written on box of the CCFL kit. I don't have any other information on where was this measured. Yes, 12 V goes into the inverter, 680 V coming out of it. 230 V goes into the PSU. (230 V, 50 Hz) – Lubomír Jan 24 '20 at 15:38

1 Answers1

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Just to make it clear: you're right that you should extend the 12 V side, not the 680 V. Not only should the bulb side wiring be short, it must also have it's insulation in good shape.

680 V @ 5 mA is about 3.4 W
By the 12 V side, that's around 360 mA at a low 80% efficiency for the inverter.
Low enough power that you shouldn't worry much about your method for extending the existing 12 V wiring.

For a very clean setup, you could buy Molex pins that can be crimped with a pair of pliers and 20 AWG wire to run from the PSU to the inverter without splicing anything. That's what I'd do.

If you want it cheaper, you could safely get away with cutting the existing wiring and soldering or using a butt connector to extend the additional 7½ meters.

RaphaelP
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  • Thank you very much. The bulb side wiring seems to be about 50 cm long when using the original 30 cm extension cable with special insulation. I wouldn't extend it any more. I am aware of that the insulation must be in a good shape and I have read now more information on how to properly handle the lamps and wires to avoid danger. I'm not an electrotechnician, but I know how to make an insulated connection of two wires, so hopefully it will be alright. By the way, there is the ON/OFF switch, and I want to use it. And thanks for the tip on using butt connector, I didn't know about it. – Lubomír Jan 24 '20 at 17:53