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MCB breaker keeps tripping
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<blockquote data-quote="Doc Hudson" data-source="post: 485620" data-attributes="member: 1607"><p>The problem here is you are looking at your symptoms in relation to one particular characteristic of the item your are powering. (i.e. inrush currents from your welder). But you forget that ALL electrical circuits must be designed to fail-safe so that fuses or breakers will disconnect the power before either the circuit, the property, any people or animals will not be harmed or injured in the event of a fault.</p><p></p><p>So if there was an overload fault caused by someone cutting the cable or sticking a nail in it and shorting out Live &amp; Neutral (or earth), The fuse must be the weakest link in the circuit NOT the cable. If you look up the current capacity of your cable you will find it is not designed to carry 40Amps. So a while a larger rated MCB may stop your in-rush problem, it would not protect the cable so it will not comply with BS7671 wiring regulations.</p><p></p><p>Just because something worked before did not mean it was safe or correctly wired. With the old fuse box you could have plugged in a washing machine wired between live and earth and it would have worked. The logic of it worked before so it must have been ok is a flawed concept. Just as I can use a car with bald tyres, no seatbelt, no airbags, worn break-pads, but as long as I get to my destination it must be ok? It is not, and it IS dangerous!</p><p></p><p>Doc H.</p></blockquote><p></p>
[QUOTE="Doc Hudson, post: 485620, member: 1607"] The problem here is you are looking at your symptoms in relation to one particular characteristic of the item your are powering. (i.e. inrush currents from your welder). But you forget that ALL electrical circuits must be designed to fail-safe so that fuses or breakers will disconnect the power before either the circuit, the property, any people or animals will not be harmed or injured in the event of a fault. So if there was an overload fault caused by someone cutting the cable or sticking a nail in it and shorting out Live & Neutral (or earth), The fuse must be the weakest link in the circuit NOT the cable. If you look up the current capacity of your cable you will find it is not designed to carry 40Amps. So a while a larger rated MCB may stop your in-rush problem, it would not protect the cable so it will not comply with BS7671 wiring regulations. Just because something worked before did not mean it was safe or correctly wired. With the old fuse box you could have plugged in a washing machine wired between live and earth and it would have worked. The logic of it worked before so it must have been ok is a flawed concept. Just as I can use a car with bald tyres, no seatbelt, no airbags, worn break-pads, but as long as I get to my destination it must be ok? It is not, and it IS dangerous! Doc H. [/QUOTE]
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MCB breaker keeps tripping
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