Where is the circuit breaker connected in an electrical installation? Is it on the live line or on the neutral line of the generator? Why?
Connection of the circuit breaker
mainswiring
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Left goes to mains, middle to your appliance, right goes to ground (maybe via a resistor??). The difference between 5503 and 5508 is that 5503 disconnects both sides of the lamp when off, while 5508 keeps the ground side connected. So the '(un)switched neutral' refers to the neutral of the lamp only.
I don't see the purpose of the 'disconnect the lamp's neutral': the other side of the lamp is still connected to the neutral via the load, so for safety purposes it is still connected.
The neutral is NOT safe to touch.
When everything is working correctly, it should be at most a few volts from ground. However, and this is the big gotcha, if there is a break in the neutral line between where you are and where it is connected back to ground, it can be driven to the full line voltage. Basically in that case you are connected to the hot line via any appliances that happen to be on in that part of the circuit. Those can easily pass the few mA it takes to kill you.
This is not supposed to happen, but since failures can be lethal and costly, a extra layer of safety is built into the protocol and rules. It is irresponsible and needlessly risky to consider the neutral line safe.
This is why modern appliances either have two prongs and everything is insulated from the user, or three prongs and anything conductive the user can touch is connected to ground. In some past cases there have been appliances with polarized 2-prong plugs, but those are seriously frowned upon today. I don't think you're going to get UL approval for such a device unless it is fully insulated, in which case you shouldn't need a polarized plug.
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Best Answer
Circuit breakers are always found at the location where the size of the wire changes. For example, when wiring enters your house and splits off to your lights and outlets the gauge of the wire is reduced to make running that wire more practical. When the gauge of the wire is reduced a circuit breaker is installed. This is evident in the circuit breaker panel of the house. The reason for this location is because when the size of the wire is reduced the safe current capacity is also reduced. If the circuit into your house is 400A capable, the wires in your walls could glow red hot and not blow the 400A fuse on the electric pole outside. Therefore the breaker is sized in a way to protect the wiring.
The circuit breaker is always on the hot side. The neutral line is just a return line. If the circuit breaker was on the neutral side then only the wiring from the breaker to point were the neutral wires all tie together would be protected. This is because a circuit breaker is meant to protect not just form over current but also against a short to ground. If a short were to occur on the hot side then the current would bypass the breaker on the neutral side. Further if the breaker was on the neutral side and turned off, everything else would still be electrified. When the breaker is on the hot side and is turned off only the bus bar inside the panel remain electrified.