What Is the Difference Between an Excavation and a Trench?

You’re getting ready to dig a hole in the earth. The best piece of excavating equipment to use depends in part on what kind of hole you’re digging — specifically, whether it’s an excavation or a trench. Exactly what is the difference between an excavation and a trench? Here’s the short answer: An excavation is any man-made cut or cavity in the ground. A trench is a narrow excavation. Just as all squares are rectangles but not every rectangle is a square, all trenches are excavations but not all excavations are trenches.

Trenching and excavating each pose their own challenges. Learn more about the differences, and when to use a trencher vs. an excavator, below.

Excavation vs. trench: Size, shape and depth

The difference between a trench and an excavation comes down to the size, shape and depth of the cut.

Excavation definition

An excavation is any man-made cut, cavity or depression created by removing earth. An excavation can be any size, shape or depth. If you’re laying a foundation, digging out a swimming pool or even leveling a driveway, you’re excavating.

Trench definition

A trench is a narrow excavation made below the ground’s surface. Trench width can’t exceed 15 feet, and it is usually much less than the length of the trench. The trench depth is more than its width in most cases.

Trenches are typically used for placing drainage lines, laying electrical wire and cable, installing plumbing and sewage lines, and installing and repairing pipe.

Trencher vs excavator: How to choose

You can’t dig an excavation with a trencher, but you can dig a trench with an excavator. The choice comes down to speed and efficiency.

An excavator is versatile

An excavator is a versatile excavating machine that can be used for excavation, demolition, material handling, landscaping, and yes, trenching.

Many contractors use an excavator for trenching because that’s what they were taught, or because they already own an excavator and know how to operate it. But you’re unlikely to get the crisp edges and graded floor that you’ll get with a trencher, and you’ll spend extra time and money digging the trench and hauling in backfill to get it to meet the required specs.

A trenching machine is specialized

A trencher is a precision machine designed for digging trenches. It’s often faster, more efficient and less expensive to dig a trench with a trencher than with an excavator.

These machines, which come in ride-on and walk-behind versions, can create trenches that have a consistent width, a graded floor and straight walls. That’s especially helpful if you’re trenching on landscaped property. Some trenchers, including those with a rock saw wheel attachment, can cut through dense rock. So can an excavator, but with an excavator you may need to switch back and forth between a hammer attachment and the bucket.

A trencher machine is efficient for trench digging because once you set the digging depth and cutting width, it digs straight through the ground and places the soil on the sides of the trench in one continuous, forward movement. To dig with an excavator, by contrast, you need to set the bucket teeth into the ground, curl the bucket to fill it, then swing the bucket to the side and dump it. In many cases a trencher will dig a trench about three to four times faster than an excavator can.

A trencher digs only the necessary amount of material, whereas an excavator creates the need for more backfilling. A trencher also makes it easier to backfill once a line is laid. It produces well graded spoil, which you can push in with a dozer. An excavator may dig out large chunks of earth and rock, making it necessary to purchase backfill.

Trench safety and excavation safety

Safety is a major concern on any excavation project. Cave-ins kill workers every year, and hazardous atmospheres, falling loads and equipment-related hazards all pose risks.

Employers are required to ensure that adequate protections are in place before any workers enter a trench. For example, a trench protective system (often, a trench box) is required for trenches that are more than 5 feet deep, unless the excavation is made entirely in stable rock. Understanding trench safety requirements is essential to keeping workers protected.

In some cases, depending on the size of the space, how workers will access it and how much time they’ll spend inside it, a trench or excavation may be considered a confined space. If it is, additional safety rules apply, and you may need a competent person to perform certain activities, including determining the best protective system and inspecting the trench, the protective system and the adjacent areas at least daily.

Knowing the difference between a trench and an excavation is key. It will help you understand the protective measures you need to take and choose the best piece of equipment for the job. If you’re digging trenches only occasionally, you can likely get by with an excavator. If you find yourself digging trenches regularly, or you’re renting a piece of equipment specifically for a trenching job, a trencher is probably the way to go.

Trenching jobs are complex and you should always consult with an expert regarding the specific circumstances, applicable rules and regulations related to your site and to your situation.

Visit our online marketplace to browse our selection of excavators and trenchers.