Is the Hot wire more insulated than the neutral? If so, why? If the current is the same at all points in a circuit, the neutral wire will carry all the current coming in from the hot wire back to ground...so why have less insulation for the neutral wire?
Also, why do we need a third prong when the neutral is already connected to ground? Is the third prong only there to overcome the hazards of faulty wiring (hot to neutral socket and neutral to hot socket)? If so, can't the third prong be wired incorrectly as well (albeit very rarely)?
Is it true that the third prong is grounded close to the building and the neutral is grounded far away at the power station itself? If so, why?
My answers refer to common residential practice in the US.
No. They have the same kind of insulation. Hot is normally black (may be red if second hot is used), neutral normally white. The safety ground wire is either uninsulated or insulated with green or green with yellow stripe.
Where have you seen less insulation on a neutral?
The safety ground conductor is there to keep conductive parts of appliances at a safe potential (with respect to the Earth) in the event of leakage between the hot wire and those parts, or to blow the fuse or circuit breaker on the hot wire, in the event that the hot wire comes into contact with the exposed conductive parts of an appliance.
No. Both are grounded at the power panel. This provides a low resistance path back to the fuse or circuit breaker in the hot to case short situation.
The neutral is also grounded outside at the distribution transformer that performs the last voltage step down to the residential voltage of
240, center tapped. The center tap is what is grounded.
All the socket wirings I've seen had similar appearance for neutral and hot wires (except the color). Someone told me they have different insulation...so I assumed the wires can potentially have different insulation even if they appear the same from outside.
I understand this need for grounding the conductive parts of the appliance, but why can't the neutral wire be used for this?
All the socket wirings I've seen had similar appearance for neutral and hot wires (except the color). Someone told me they have different insulation...so I assumed the wires can potentially have different insulation even if they appear the same from outside.
I understand this need for grounding the conductive parts of the appliance, but why can't the neutral wire be used for this?
The fact is that a "protective or safety earth " must be INDEPENDENT of the AC power supply circuit and so cannot be also current carrying conductor.
An appliance with the neutral connected to its own metal housing would become LETHAL if the neutral pin failed to connect properly to the AC outlet while the active connection was OK.
Around here (California) the ground is local, a big pipe or something near the breaker box, and the neutral is grounded somewhere down the block, at the distribution transformer. I once had an open neutral in my old house, and one ac phase went up to about 140 volts while the other dropped to about 100. The bad connection was up on a pole, across the street and down the block a ways. Neutral and ground are generally not connected within a residence.
** They are *most certainly* are linked WITHIN premises in most other places ( UK, Australia & much of Europe) - basically any place that uses the " MEN " system.
California is the home of " fruits, nuts and loops " so no surprise it is out on a limb.
Because of Ohm's law. The neutral wire is a resistor somewhere between zero and infinity ohms. It is connected to the hot wire through any load. Its voltage at the load end is dependent on its resistance and the current passing through it. Normally, one expects its load end to be within a few volts of Earth potential, but would you want to trust your life to all the connections back to its grounding point being tight? The safety ground conductor also obeys Ohm's law, but is not normally loaded with up to its rated ampacity with load current. It is expected to pass only leakage current, or to briefly carry a fault current, for as long as it takes to open the over current protective device (fuse or circuit breaker on the hot side).
Hot, only. Once the hot conductor is opened, the neutral is just a wire connected to ground, so it helps bleed any leakage current that gets through the breaker and the load that popped it.
If the load is connected between the to opposite hot wires (240 volts) then a double breaker is used, that opens both hots if either or both experience an over current. In that case there is no neutral, only two hots and a safety ground.
If they are connected, it is only at the main breaker, and called Bonding. Some areas require it, while others outlaw it, depending on local soil conditions.
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Michael A. Terrell
Central Florida
i don't see why CA is not to follow the NEC rules? the ground you are referring to is the electrode and thus is used to connect your breaker box case and in that box is the bus bar for the earth ground a long with the neutral wire.. no where else is neutral ever to connect to an earth ground or the ground you run out of the box with your 3 WYE..
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