CSLB C-46 Solar ContractorPlanning and EstimatingMedium
A C-46 contractor is preparing an estimate for a ground-mounted PV system. The site requires extensive trenching for DC and AC conductor runs from the array to the inverter and main service panel. Which of the following is the most significant cost driver for this specific part of the project?
- ALabor for excavation and backfilling.
- BCost of the underground conduit.
- CPermitting fees for trenching.
- DPrice of the conductors themselves.
Show answer & explanationAnswer & explanation
Correct answer: A. Labor for excavation and backfilling.
For extensive trenching operations, the labor involved in excavation (digging), laying conduit, and then backfilling the trench is typically the most significant cost driver due to the time and equipment required, far outweighing material costs.
Why the other options are wrong
- B. While conduit costs money, it's generally less than the labor for extensive trenching.
- C. Permitting fees are a fixed cost and usually a minor portion compared to the labor and material costs of the physical work.
- D. Conductor costs are substantial, but for extensive trenching, the labor associated with earthwork often surpasses it.
Trenching Cost Drivers
Factors that significantly contribute to the expense of excavating and installing underground conduits for PV systems.
- Labor is often the highest cost for earthwork.
- Soil conditions and terrain impact excavation difficulty.
- Distance and depth of trenching directly correlate with cost.
Memory trick: Digging Labor Costs Most.