We like this saw, but it has some shortcomings: It's rated at 20 amps and has a tendency to blow breakers during heavy cutting. It did this repeatedly the first couple of times we put it to work, even though we were using 20-amp circuits with nothing else plugged into them. In hindsight, I chalk the problem up to a number of factors: The concrete was really hard, the homes were old and had questionable wiring, and we may have pushed too hard during the cutting. We had better luck on later projects because we switched from a 12- to a 10-gauge cord and eased off on the feed rate when we heard the motor straining. It was similar to ripping framing lumber on a portable table saw – push too hard and the breaker will blow.
I mentioned this problem to a Hilti sales rep and he recommended running the saw off a generator, as would be the norm on a commercial job site. This would probably work – but for us, using a generator would offset the convenience of using an electric tool. The saw is equipped with a 20-amp twist-lock fitting, and to run it on household power you must use a supplied cord adapter
to convert it to a three-prong plug.
The Bottom Line
The DCH 300 solves a longstanding problem on remodeling jobs: how to cut concrete without sending dust and fumes all over the place. However, it's quite a bit slower than a gas-powered model. It's best-suited to making "surgical" cuts, like opening up a slab or cutting window openings in basement walls. For big jobs, or where dust and fumes are not a concern, you are probably better off using a gas-powered saw. Personally, I'm going to hold on to our gas-powered saw but use this one for cutting through slabs in cases where dust and fumes are objectionable.
Greg DiBernardo owns Fine Home Improvements of Waldwick in Waldwick, N.J.
Blade diameter: 12 inches
Maximum depth of cut: 4 3/4 inches
Motor: 20 amps
Speed: 4,300 rpm
Weight: 20.7 pounds
Price for saw: $890
Includes: saw, wrenches, 15/20-amp cord connector
Price for blade: $166
Price for VC40-U vacuum: $933