New Electrical Work

No, on a service change all the wires have to be able to carry the current of the highest rated device.

There are tow cables associated with your question. The one from the pole to the meter and the one from the meter to the main electric panel. The one to the meter is the responsibility of the power company and may well be large enough. Since it is in free air its current carrying capacity is not de-rated in the same way as the cable from the meter to your main panel. Since you will have to likely upgrade your main panel it is a good idea to replace the service entry cable to 100 A rating.

depends on size....

Deburring.

Basically the circuit to the lamp opens and closes in a specific amount of times per minute. In some models this can be varied with a control circuit that allows the operator to set how many times the lamp is to flash per minute.

steel and plastic conduits

The first electrical circuit was created by an Italian physicist named Luigi Galvani in the 1780s. He discovered a frog's leg would twitch when touched with two pieces of metal. His work was taken up by Professor Alessandro Volta. He created the Vollaic pile. The pile consisted of discs of zinc and copper with pieces of cardboard soaked in brine between the metal plates. It was the first "wet cell battery". This principle is used similarly today but the metals and fluids are quite different.

You have to check the label on the unit itself. It will give you all the information as far as maximum and minimum amps.

Never assume that any electric wire, no matter what color it has, is safe to touch.

Using the AWG for wire sizes only goes up to 4/0. After that the increases use MCM to size the wire. So your 262 MCM wire size will be same in AWG. There is no 262 MCM in the North American market place. It goes in 50 MCM increments starting at 250 MCM , 300 MCM, 350 MCM, 400 MCM right up to 2000 MCM cable.

If you are adding the pull chain to an existing fixture then the pull chain switch should have two wires. Wire nut either one to the hot wire coming in and the other to the black wire of the fixture.

The voltage of 277 volts is the wye voltage of a three phase 480 volt distribution. In the 480 volt CDP (Central Distribution Panel), you will need a 600 volt rated single pole 15 amp breaker installed in the CDP. The load will be connected to the output terminal of the breaker and the other conductor will be connected to the neutral bus in the CDP. The minimum size conductor for the 15 amp circuit will be a #12 copper conductor.

A 14 gauge extension cord can safely carry 15 amps, but not very far. Number 14 gauge extension cords are only rated for about 13 amps according to the labels on the cord. This is because the insulation is not intended to withstand the heat of currents above this level. Running this cord over 50 feet or loading it to 18 amps would be unacceptable.The likelihood of the cord maintaining the 18 amps for any amount of time for the high current to do any damage to the insulation of the cord is not very great. Extension cords are only an extension of the 15 amp wall circuit that they are plugged into. On overloading the extension cord by that amount the overload will trip the 15 amp supply breaker. An example of this is jamming a circular handsaw when it is plugged into the end of a 50 foot extension cord. The next action that is taken is to reset the tripped breaker.

yes. The higher the number the smaller the wire.

They're usually just a 120 volt circuit. Check the label on the unit. Very minimal power draw. Possibly an amp or two.

Yes. Can be white or yellow or orange. Depends on gauge. Some older wire is also black.

Kilowatt hours.

The term "wall cavity" usually refers to the space between studs. Outlet boxes are usually fastened to one side of a stud or the other. Sometimes they are fastened to a crossbar, whether metal or wood, so they can be placed anywhere within the space. There are height limitations in order to count as required outlets but may be placed anywhere you need one. They are called convenience outlets and my friends often hear me say that if one isn't convenient, there aren't enough.

If by "wall cavity" you mean a completely walled off portion of a building with no access, something that sometimes happens in commercial buildings, then no, it is not legal. You must have access to any splices in the circuit, which includes end of the line.

2 ft would be the maximum.

on a 4000 watt amp the best gauge wire woul be between 2 and 0

To answer this question the voltage needs to be known.

Depends on what it is powering. The longer the run the more voltage drop you get. For example if you run 200 feet of copper 10 wire you'll lose about 4 volts. There are voltage calculators you can use. The less volts you have the more amps the wire will have. Watts/volts=amps. 10 wire is rated for 30 amps. Do the calculation. You should not go past 80% of 30 amps (24 amps).

No More than 1/2" into any Raceway Fitting or Box for NonMetallic Cables. Armored Cable (Type AC) or MC should seat to the end of its associated UL Listed Fitting with the Correct Antishort/RedDevil bushing inserted into the end of the cable to protect the wires.

Yes. It just won't be as bright.

The voltage needs to be known to give an answer to this question.