Side by Side: Trenchers vs. compact excavators

Popular, affordable and highly productive, these two machine types have helped lay a lot of cable and pipe in the ground in the last few years. And while both can do the work, we asked two experts from Ditch Witch – Brent Bolay, senior product manager over trenchers, and Mike Lumbers, senior product manager over compact utility products – how these two machines stack up against each other in residential utility installations.

Size and price
The average dig depth for utility installations in residential applications is between 40 and 48 inches, Bolay says. A basic trencher that digs to this depth will have a 20- to 30-horsepower engine and cost in the neighborhood of $35,000 to $40,000. The most popular compact excavator, Lumbers says, is the 2.5-metric-ton size class, and it also uses a 20- to 30-horsepower engine and costs about the same. A big difference emerges when you need a trencher to go deeper. The 2.5-metric-ton excavator has no trouble digging to 8 feet or more, but a trencher that can go that deep will require an engine with 100 horsepower or more and cost up to $90,000.

Lifecycle costs
Except for bucket teeth and the replacement cost of the rubber tracks at 1,500 to 2,000 hours, fuel and regular maintenance are your only day-to-day costs with a compact excavator, says Lumbers. The teeth, digging chain and sprockets on trenchers are considered wear items and are replaced fairly often, Bolay says, something people unfamiliar with trenchers need to be aware of. Yet even with the trencher’s higher consumable costs, the differences tend to even out when its productivity is taken into account.

For straight-line trenching at average depths on unencumbered jobsites, trenchers flat out take the lead. Under good conditions a trencher can work three to four times faster than an excavator, Bolay says. “If it’s a fairly open jobsite and there are not a lot of underground or surface obstacles, you can work productively and leave a cleaner jobsite with a trencher than a compact excavator,” he says. Another place where trenchers excel is in wooded areas where tree roots make for sloppy, slow digging with a bucket. “But if you’re working in a housing area and you have short runs and underground obstacles a compact excavator might be the right choice,” he says.

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Compact excavators can do a lot of things a trencher can’t do, especially when outfitted with attachments. “With a compact excavator you shouldn’t have a foot-per-minute goal,” Lumbers says. “It’s a good choice if you’re looking for a piece of equipment that you can keep busy on the jobsite for different tasks such as setting utilities, using a hammer or a grapple, or doing pit work.”

But a trencher is not a single-minded machine either. Many can be outfitted with a backhoe attachment that fits on the front end. When rocks, concrete or asphalt stand in your way, the boom and chain can be replaced with a wheel and rock teeth. And in soft soils, you can set up a trencher with a vibratory plow attachment and plow in cables faster than any other method.