Ten feet is roughly the boundary between the 3-ton and 4-ton classes, and it's where a lot of utility, septic, and foundation work sits.
Getting there costs you access and transport ease.
Which Classes Reach It
| Class | Typical dig depth |
|---|---|
| 3 ton | ~8–10 ft — top of the range |
| 4 ton | ~10–11 ft |
| 5 ton | ~11–12 ft |
| 6–8 ton | ~14–15 ft |
A 3-ton at the top of its range reaches roughly 10 feet, but you'll be working at maximum depth — which is slow and awkward.
4-ton and up gets you there with margin, which is what you want for regular work at that depth.
The Long Arm Option
Many manufacturers offer a long-arm or extended-dipper configuration that adds depth and reach on the same base machine.
What you gain: typically a meaningful depth increase without moving up a size class.
What you give up:reduced breakout force and reduced lift capacity at reach. You've increased the lever arm the cylinders work against.
Worth it if you consistently need the depth and your digging is in reasonable soil.
Not worth it if you dig hard material — the force you lose is the force you need.
What You Give Up Going Bigger
Access. A 4–5 ton machine won't fit residential gates. If you also do tight work, you may need two machines or a rental.
Transport. This is the bigger issue.
- 4 ton (~9,000 lb): one-ton truck territory
- 5 ton (~11,500 lb): one-ton with a gooseneck, generally
CDL thresholds become reachable. A combination rated over 26,000 lb GCWR with a trailer over 10,000 lb generally triggers Class A requirements — and rated weights, not actual load, are what count.
Cost, both purchase and operating.
Do You Actually Need It?
Worth checking before you size up.
Get your actual requirement from your building department, utility, or system designer:
- Frost depth for footings and water service
- Utility burial depth per local code
- Septic system design depth
These vary enormously by region. A requirement that demands 10+ feet in Minnesota may be 4 feet in Georgia.
Also consider: you can dig deeper than the machine's rated depth by working from a ramp or a bench. It's slower, but it's a real option for occasional deep work rather than sizing the whole fleet around it.
Safety at Depth
OSHA requires a protective system at 5 feet and deeper — shoring, shielding, or sloping. At 10 feet you're well past that, and the consequences of collapse are correspondingly worse.
Never enter an unprotected excavation at depth.
Keep spoil back from the edge — material at the lip adds surcharge load and increases collapse risk substantially.
A competent person must inspect daily on commercial work.
Deep narrow excavations may also involve confined space hazards — atmospheric testing requirements can apply.
FAQ
Can a 3-ton reach 10 feet?
Top of the range, some can. You'll be at maximum depth, which is slow.
Is a long arm a good option?
If you need depth in reasonable soil, yes. If you dig hard material, the lost breakout force hurts.
What truck do I need for a 4-ton?
One-ton generally, and check payload for tongue weight.
Do I need a CDL?
Depends on combined rated weights. It's reachable at this size.
Can I dig deeper from a ramp?
Yes — working down into an excavation extends effective depth. Slower but real.
What about renting up for deep jobs?
Common and sensible. Own the size you use constantly; rent when a job needs more.
How do I find my required depth?
Building department, utility, or system designer. Don't rely on general guidance — it varies enormously.