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Thread: CoC Inspection & Test Question

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    CoC Inspection & Test Question

    Under the question "Different circuits are separated electrically", does this only apply to different circuit types (ie. Communications, security, etc) of for different circuits (socket outlets and lights for example) ?

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    Diamond Member AndyD's Avatar
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    I think you might be confusing separation and segregation.
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    Quote Originally Posted by AndyD View Post
    I think you might be confusing separation and segregation.
    Probably, but with regards to SECTION 4 on the CoC which are they referring to?

    I assume it refers to the following: Circuits for control communication, security, detection, safety and the like should be electrically separated and, where specified, physically separated.

    So in premises without these other types of circuits does one normally state N/A?

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    Bronze Member ACEsterhuizen's Avatar
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    IMHO: Eg: Light circuit originates from bottom of breaker, feeds to switch then to and through the load (lightbulb) back to DB through a N.

    If you know feed that same lightbulb let's say from another source, let's say you get a L from another source (breaker) in the same DB (or heavens forbid from another DB - i have seen this) and feed that L through a switch to the same lightbulb in order to switch the light on from 2 different locations. (2-way or intermediate switch to much hassle)

    Now you have a circuit that is not electrically separated. It is not separated from other circuits as it is now joined. You switch off your breaker, even remove the L and proceed to the light fitting to do maintenance.

    Meanwhile the other switch feeding from the other source is closed, thus live and "backfeeding" the circuit and now your circuit, which you removed from the bottom of the breaker and/or the first switch is live. With most lights not on an E/Leakage you suddenly stand with a cocked, loaded gun in your mouth and you think it is a lollipop.

    The circuit was not electrically separated from other electrical circuits.

    Above scenario is on purpose but the conductors can also "burn through" and make other circuits live unexpectedly.

    This is how I was explained to back in 1986.

    PS. the neutral is also part of the circuit. It must be separate too and not part of any other circuit.

    http://electriciancentre.co.uk/how-t...tion-circuits/
    Last edited by ACEsterhuizen; 14-Mar-16 at 12:55 PM. Reason: clarify

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    Interesting topic, I'm always finding that guys are connecting eg. All light circuit neutrals together in roofs or sometimes sharing a thicker earth cable between two circuits instead of having two separate thinner earth wires.
    On my opinion each circuit should have its own neutral wire and own earth wire, and the only place these wires from different circuits should be connected together is in the DB on the earth or neutral bars.
    I think it's pretty obvious not to mix lives.
    If you interlink neutrals on a plug circuit inside the home you may end up having to disconnect more than one plug circuit when experiencing earth leakage tripping on a neutral fault before repairing.
    Having circuits separated completely makes fault finding much simpler and in the case of a live to earth fault somewhere, as little equipment as possible will be subjected to this fault voltage.
    That's what I think anyway

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    Gold Member Sparks's Avatar
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    It is my understanding that each circuit shall have it's own neutral. Not only will that reduce the chance of electric shock, but also aid fault finding. Neutrals are to be connected to a neutral bar so that each circuit can be individually disconnected. This is how I interpret "electrically separated". A light fitting/appliance may have two separate supplies provided it is labelled accordingly.

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