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Thread: Incoming Supply and Prepaid metering.

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    Incoming Supply and Prepaid metering.

    I have come across many prepaid meters installed by the municipality that is quite sub-standard. They are mostly mounted next to the existing distribution board. and a piece of concrete plaster knocked out of the wall or a slot cut in the DB cover to route the mains through them. If the mains are too short, an extra piece of wire is joined on and the connection taped up. The part that concerns me most however is the fact that they usually feed the existing main breaker from the load (output) side. Although this is probably not illegal, it is not the conventional way. In my experience the main switch was supplied from the top and then a bridge inserted from the bottom (load) side to supply the rest of the installation on the top (supply side). Most breakers are not marked, so I assume that any side could be used for supply. It seems that the reason they do this is is to save space in very crowded distribution boards. In a few instances I have also come across double pole isolators supplied from the "conventional" load side. Is this practice acceptable? (Reg.6.8.2.3)

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    Morning Henthal

    This is a very interesting point.

    I don't believe that you would be able to use any side as a 'live' or 'load' side unless clearly indicated by the manufacture.

    I have attached a picture of the inside of a circuit breaker and you will see label 12 which is the bottom is the output/load.

    I know that most breakers don't have live and load on them but they do have a diagram on them and normally numbers, 1 on to then 2 underneath on the diagram and so on.

    Click image for larger version. 

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    Thank you SeanM. The interesting part is that I don't think it will make a difference to the tripping. The load or overload will be sensed through the whole conductor, load or supply side. I am more concerned about the ethical issue. We are so used to the conventional wiring that someone may assume a wire on the load side is "dead" with the breaker switched off. I just feel that it is bad practice not to follow convention. Also, I am not sure if all breakers are insensitive to the way you wire them. There may be a technical issue of which I am not aware.

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    Conventions vary from place to place, in SA residential installs it's the norm to have supply at the top and load at the bottom, in the UK for example it's vice versa and in the USA the breakers are often mounted horizontally in 2 columns with the busbar in the centre which is similar to them being supplied from the top in this country. As Sean mentioned, whether it's electrically acceptable to supply a circuit breaker from the top or the bottom would depend on the diagram on the breaker itself and the manufacturers data sheet information, some are designed to have the supply on either side and some only from one side.
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