Looking to purchase a trenching bucket for a 3.5 ton mini. Trying to decide whether to go with 10" or 12". Mainly to run lines and 4" pvc or big o for drainage. Obviously the more material that comes out the more (purchased) aggregate needs to go back in. As well even with a 12" bucket you pretty much end up with a 14" or so trench depending on soil conditions. That being said, couple of my buddies that have excavators said they would go with 12". The only draw back with a 10" bucket that I can see would be clumping in the bucket during wet soil conditions and hard to walk in a 10" trench. What size would you get and why?
We run a 12" bucket on our Cat 303 for trenching, the bucket its self is only 10" and the teeth and side cutters make it 12" if that makes any sense. Unless your digging through loose fill the dirt will always stick in the bucket. Clay gets really bad, one thing we did is bolt a piece of 3/8ths" chain from the top middle of the bucket under the ears down to by the teeth through the center of the bucket, this helps chew the dirt up as you dig through it and helps to keep it from sticking.
I run a 14" /(350mm) bucket on my Bobcat E35 and have done on my past 3.5ton machines. We find its too hard to work in laying drains 4" /(100mm) using a 12" bucket and once the trench becomes the depth of your hips or shoulders you cant work in it anyway.
Iagree diga,100 mm under,and over and either side of drainage pipe is minimum legal sand cover ,so 100 pvc dwv pipe requires 300mm bucket trench width minimum.
12" for conduit and cable, 18" for working in trench