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Does 2005 nec code require tamper resistant outlets?
No, but the code as of today (2012) does require tamper proof outlets.
Which standard covers the cable sequence in cable trench?
The CEC and NEC both cover this in the electrical code of the particular country.
Is it necessary to ground at all metal junction boxes when using metal conduit or cable?
In a completely metallic conduit system it is not necessary to ground each junction box as long as the metallic system has the grounding capacity rating larger than that of the over current device protecting the circuit. The code book states what size conduits are rated at, for grounding amperages.
Why are you only allowed 360 degrees of bend jn a electrcal condit run?
Any more than four 90 degree bents (equaling up to 360 degrees) or a combination of other bends will make it quite difficult to pull the wires into that pipe. This is why the electrical code prohibits more than 360 degrees. If you have to put more bends than that, place a junction box on the line after the first 360 degrees. This way you pull to the junction box and then use that junction box so continue the rest of the way.
Can a fire start in a junction box?
That is the most likely place for a fire to start. It is at this place in a circuit that mechanical connections break down. Loose splices create oxidation on the wires, oxidation creates a higher resistance creating a current draw through the resistance. This heat can become high enough to melt the insulation off of the wires. The heat build up is accumulative and the current might not be enough to trip the breaker. Junction boxes used to be made of steel which contained any flames from the surrounding wood structure. Now days boxes are made of a non flammable plastic which are sealed to cut off any oxygen to a fire that may start in the junction box. This is why the code calls for any splices that are made in a wire to be made in a junction box, and the junction box has to be accessible. There are documented cases where the junction box has been buried behind sheet rock and plaster walls and a fire has started and no one noticed until the fire burned through the wall.
