50 meter cable run for 2way lighting

[Chris Dolby]

i have been doing cable size calculations and just cant get this to work out. i mite be missing something.

here are the numbers ive got to work with. theres 10 72w fluorescent fittings so need to be x by 1.8??) on a 6A cb. the two way switches need to be 50m away from original switches. the problem i keep getting is volt drop not being inside the 3%. surely this must be possible to do in 1 or 1.5mm three core. or will i have to split the lights up onto more switches???

 

[roukel01]

have the light switches control a relay rather than the load of the lighting.

 

[SimpleSimon]

have the light switches control a relay rather than the load of the lighting.

Good thought.

 

[Chris Dolby]

have the light switches control a relay rather than the load of the lighting.

spot on, thanks. havent ever bin asked to do such a long run for a 2way,
something i am also unsure about is when calculating cable size for a 2way for the strappers would you double the distance of the three core length, because the live travels down one wire and back on another. just wondered if anyone had any input???