A trench box is hired by the week rather than the day, and a common 6 foot by 8 foot aluminium or steel box runs roughly $200 to $500 with the spreader pipes included. It is protective equipment before it is plant: OSHA requires a protective system in any trench 5 feet deep or more unless the excavation is in stable rock.
Depth is what makes it mandatory
OSHA requires cave-in protection in every trench 5 feet deep or greater, and permits a competent person to waive it only where the excavation is entirely in stable rock. Below 5 feet a box is still required if that person sees a hazard. Sloping, benching or shoring are the alternatives, and on a narrow street a box is usually the only one that fits.
Specifying the box
Boxes are sized by height and length, from 4 by 6 up to 8 by 24, and the spreaders set the clear width for the pipe and the crew. Every box ships with a tabulated data table stating the depth and soil type it is rated for. Read that table against the trench you have, because a box outside its rating is decoration.
Getting it in and out of the ground
A steel 8 by 20 box weighs several thousand pounds, so the excavator hired to dig the trench has to be big enough to lift, place and pull it. Aluminium boxes weigh a fraction of that and suit a mini excavator, which is why they cost more per week. Ask the counter for the shipping weight before booking the machine.
What the weekly rate covers
The rate covers the box and its spreaders. Delivery is charged each way on a flatbed and is often the larger line on a short hire. Extras that get added late are the second set of spreaders for a wider trench, stacking pins to double up in a deep dig, and a ladder, since the trench also needs a means of exit every 25 feet.
Questions people ask about trench box rental
At what depth is a trench box required?
Five feet. OSHA requires a protective system in any trench 5 feet deep or more, other than one dug entirely in stable rock, and a competent person can require one at a shallower depth if the ground shows a hazard.
Can I put a trench box in myself?
Placing the box is machine work, done with the excavator already on site, and it is normally lowered into a partly dug trench and pushed down as the dig continues. The counter hires you the box, not the method, so the competent person on your job owns the plan.
Are trench boxes rented by the day?
Rarely. Most yards run a weekly minimum because the transport dominates the cost, and a trench that is open at all is usually open for several days. Monthly rates are common on utility work.