For more information see the answers to the Related Questions shown below.
Please read the important advice shown next.
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Just by asking this question you are probably not quite ready to take on this particular task.
If you hope to get enough information on this site to be able to do this job properly and safely, please do not rely on getting accurate information about such a potentially dangerous subject.
Really, don't do this one yourself. Electricity is far too dangerous to handle if you have not been trained how to do this work. If you put just one wire in the wrong place you risk being killed by electrocution or you could even start a house fire.
How to do this job depends entirely on the Wiring Codes or Regulations for the locality (Town/State) and on the exact location of the fittings you wish to install. If they are anywhere that is subject to water splashes or spray - such as in any room supplied with running water pipes, like a kitchen, bathroom, shower room, etc., or in a pool-side area - in many places nowadays it is actually illegal to attempt to do this kind of work unless you are already a licensed electrician.
If you don't want to go to your local library or bookstore - to find and read some books about electrical wiring and appliances and how to install them safely, and to find out about your local Wiring Codes and Regulations - then the best advice anyone should give to you is to call a licensed electrician either to do the job for you or to advise you what you may be allowed to do yourself.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
Yes, you install a GFCI on a 2 wire circuit.
At 120 volts a 15 amp circuit wired with #14 wire used for a dedicated light circuit do not install any more than 1400 total watts in lighting. If used for an dedicated outlet circuit do not install more than 8 outlets.
A GFCI can not be used on a three wire branch circuit. It has to be on a single two wire circuit.
Just install the new fixture with black to black, white to white, and cap off the ground wire on the new fixture. It'll be fine.
If they are on the same circuit you only need 1 neutral wire in the circuit.
No. In a 20 amp circuit all wire has to be 12 AWG or larger.
When one wire or terminal is not connected to a light bulb, it is not possible for electricity to complete the circuit. When a circuit is not completed, the bulb will not light. An off switch, for example, breaks the circuit.
Usually 15A or 20A, but it depends on the wire used.
NEC states that all GFCI's require a 20 amp circuit, the wire size for a 20 amp circuit is 12 gauge.
Mood lighting in the car can be done by connecting LED lights to the rest of the battery circuit. Disconnect the negative cable and connect the LED light connector to the circuit that leads to the rear lights.
Cannot answer this question. Will need to know the voltage and amperage of the circuit. Also need to know the application i.e. is it a lighting circuit or a motor circuit?
In residential wiring applications the most used is 14 gauge wire for light switches as long as the circuit breaker or the fuse is 15A. If your lighting circuit is on a 20A fuse/circuit breaker then you need to use 12 gauge wire