Almost every home network uses ethernet cables to get in touch either their modem for their router or their routers on their computers. Fiber cables transmit light instead of electrical current. STEP 2 - Inspecting - Inspect the newly revealed wires for any cuts or scrapes that expose the copper wire inside. Plug your ethernet cable into the tester and see if it all the lights light up green, whenever they do then you are good, and you can get to making your other cables, when they don't you'll have to cut off the RJ-45 connector and reterminate your ends with a new connector. Use a suitable car 12v charger which might work slowly but effectively, and which will cause no harm to your car battery. Cable testing with a decent tester may be used to detect this fault whenever it takes place.