My Copper lead in cable from the pillar was only buried around 30 CM (Spade length) Deep in the ground and it's been fine for over 14 years only needed to be repaired once when watercare damaged it fixing our water meter. Ours wasn't in a conduit it was direct buried. We have fibre now which was done the same way I told Chorus I wanted 20mil ducting they laughed and said no way. they said they could do it but it would be a extra cost. so they did the spade in the grass and wiggle technique to lay the microduct. they said our ground was really hard and they wouldn't have been able to do the trench anyway. I did get them to install a 2 foot long green conduit down by the water meter just in case anyone has to dig there again. they told me the microduct is really strong and you don't need conduit they said you can't break it with a spade it just bounces and it would take a digger to break it. I actually have some Microduct in the garage cause I wanted to see just how strong it was.