Can you overload a lighting circuit

I remain flummoxed by this OP. Can you expand on the circumstances Mr Jack96? It is inadvisable to add to a lighting - or any other - circuit until it goes pop............ then decide OK - that's enough. It cant be that hard to add up whats on the circuit and decide if the additional load can fit onto the existing circuit?


You last said, "So if the cable is rated correctly for the breaker overloading the circuit will only cause the circuit to trip and no further damage? cheers guys "


This is correct up to a point...........If you loaded a 40A lighting circuit up to 60 amps, on a 6mm circuit - it would last for - about an hour I believe - perhaps more -  before tripping - repeated loading to 60Amps on a cable not rated for this would stress it out and lead to eventual failure of the cabling...... Id guess. The same would apply to any size cabling/mcb relationship I'd immagine. 


What was explained above, however, was that (Under unusual circumstances)  if the cable is too small for the MCB/fuse it's connected to, but the cable is rated correctly for the load with no possibility of there being an overload AND then cable/mcb relationship was OK for short circuit protection. Then this is OK. 


There must be graphs to show how overloading a cable repeatedly and the heat produced will degrade the PVC over time.

I remain flummoxed by this OP. Can you expand on the circumstances Mr Jack96? It is inadvisable to add to a lighting - or any other - circuit until it goes pop............ then decide OK - that's enough. It cant be that hard to add up whats on the circuit and decide if the additional load can fit onto the existing circuit?


You last said, "So if the cable is rated correctly for the breaker overloading the circuit will only cause the circuit to trip and no further damage? cheers guys "


This is correct up to a point...........If you loaded a 40A lighting circuit up to 60 amps, on a 6mm circuit - it would last for - about an hour I believe - perhaps more -  before tripping - repeated loading to 60Amps on a cable not rated for this would stress it out and lead to eventual failure of the cabling...... Id guess. The same would apply to any size cabling/mcb relationship I'd immagine. 


What was explained above, however, was that (Under unusual circumstances)  if the cable is too small for the MCB/fuse it's connected to, but the cable is rated correctly for the load with no possibility of there being an overload AND then cable/mcb relationship was OK for short circuit protection. Then this is OK. 


There must be graphs to show how overloading a cable repeatedly and the heat produced will degrade the PVC over time.