OK ,I have a 200amp service residential.I have a out building/workshop with a 100 amp main breaker panel installed. Now can I run 3 wire service to it?Bond neutral to can.
Do I place a rod there or not?
Do I run 4 wire and place rod?
I re read some past threads but need alittle
reassurance.Thanks in advance.
using direct burial cable pvc conduit.

Are there any continuos metal paths between the building? Such as water pipe, gas, coax, phone, etc...?

Not that I`m aware of at this time.I read 250.32 Not clear on the single branch part.Electricians here say you can run three wire but the best way would be go with 4 wire and the rod.Just would like to better understand if three wire is permisable in this situation legally. But also personally I`m lean towards the best way if it is better.

If your installing a panelboard at the workshop, than you don't have a single branch circuit going to the workshop, you have a feeder.

Regardless if you wire with 3-wire or 4-wire, a grounding electrode system will be required at the workshop building.

I don't think either way can be classified as "better". Both will provide adequate service and practical safegaurding.

Take a course on stray voltage and you will find out why the 4-wire method IS better than using only 3.

If you are not sure of metallic paths then you MUST use 4-wire.

Ground rod(s) are necessary at the second building.