How to connect several led lamps (G9 Connector), to a cable wire
Low Voltage For Safety
If you run these lamps directly off mains (120V - 240V, depending on region), you are, quite literally, playing with fire.
The good news is, LEDs are inherently low voltage DC creatures, not mains voltage AC beasts. So use an inexpensive UL (or equivalent) tested/certified converted to switch from mains AC to 12V (or similar, varies by application) DC. Then you can play around with the lamp wiring with much less risk of hazards, including both life safety and fire.
Electrical Tape is NOT a Primary Connection Method
Electrical tape is great for:

Labeling - e.g., mark two ends of a wire with the same color for identification, or mark with white tape and then write a number or letter on the white tape.
Extra Security - e.g., wrap a loose wire nut to keep it tight (I've seen several references to this being a good idea for a wire nut on a single wire)
Quick Patching - wrap around insulation nicked in an extension cord
Testing/prototyping - temporary use to connect wires together for purposes of testing before permanently connecting the wires

It is NOT normally for permanent wiring (low or high voltage). I've learned this over the years (with low voltage!). Basically, electrical tape (or any tape) doesn't really hold wires together. A wire nut (US) or other connectors designed for holding wires together work much better. In particular, most (all?) of these connectors have conductive metal inside them which securely contacts all of the wires, instead of relying on a manual twisting of the wires to provide all the connections.