Burial Depth 300.5

[Dzboyce]

I'm in farm country.

Years ago, the irrigation company I worked for had its own minimum depth of 5 feet (60"). Didn't matter if it was direct bury or in conduit, or just a pipeline with no electrical. Occasionally a farmer might deep subsoil his ground to a depth of 36" plus. If you're digging or trenching 36" deep, it doesn't take that much more time to go 60".

My Ditchwitch 6510 is set up to dig a 10-12" wide trench. At 60" deep it will do about 500-600 feet per hour.

In residential work my conduit is many times going in the same ditch as water lines. That means it's going to be at least 36' deep.

 

[kwired]

Just wondering what types of problems you've seen with direct burial cable...? Just being hit more often? On the tract home projects here I see the POCO and their subcontractor Site Wise going about 4 feet deep.

If we use conduit I'm thinking about how POCO will tie conduit into transformer. Looking at Article 314.30(B) it reads that the conduit shall extend into the enclosure, not sure how POCO feels about this.

314.30 is for hand hole enclosures. Though there is some similarity to pad mount transformers that have conductors leaving from below, but the padmount is either on a concrete pad or all I am seeing these days for new installs is a fiberglass base. The transformer enclosure is open bottom just like open bottom switchgear, put a bushing on end of raceway and call it done. If metal raceway might need either grounding bushing or other bonding clamp installed though.