I hate messy panels. Finding a breaker takes too long. I bought the Klein ET300 and the new ET310. I tested both to see which is best. Here is what I found.
Klein Tools ET300 Circuit Breaker Finder Review
I bought the ET300 years ago. I use it to find breakers. It stops me from turning off all the power. It is a simple tool. It has two parts. One part plugs into the wall. The other part is a wand. You hold the wand at the panel.
I tested it on an old house. The wiring was bad. I plugged the small part into a kitchen plug. I went to the basement. You must scan the panel twice. The tool beeps a lot at first. This is normal. It learns the signal. On the second pass, it finds the right switch.
It works okay. It found the right breaker. But I had to go slow. The plug part is small. It is easy to lose. It does not stick to the wand. I lose it in my bag a lot.
The side switch is bad. It slides on easily. I put it in my bag. It turned on by itself. The battery died. This happened twice. That is a bad design.
The tip is straight. This is hard to use in tight spots. I hit my hand on the wall. It is accurate if you are patient. It is tough too. I dropped it on concrete. It still works.
| Pros | Cons |
| Very easy to use | Switch turns on in bag |
| Good battery life | Easy to lose the plug |
| Loud beep | Tip is hard to hold |
| Strong plastic body | No wire check on plug |
| Fast to scan | Beeps too much at times |
Klein Tools ET310 Circuit Breaker Finder Review
The Klein ET310 is the new model. I bought it to see the upgrade. It fixes my problems with the old one. The plug part is better. It is not just a sender. It tests the outlet too. It checks for bad wiring.
I used it on a remodel job. I plugged it into a room outlet. The lights turned on. They told me the ground was open. I knew this before I went to the panel. That saves time.
The wand feels better. The tip is bent. It is easier to hold. I can scan down the row easily. My hand stays comfy.
I scan twice with this one too. But it is smarter. It does not beep as much. It finds the right one faster. It is more sure.
| Pros | Cons |
| Plug snaps into handle | Costs a bit more |
| Tests bad wiring | Must scan twice |
| Bent tip is comfy | Lights are dim in sun |
| Button is in a good spot | Tight fit in pocket |
| Uses normal batteries | Plug is a bit big |
The best part is storage. The plug snaps into the handle. It stays there. I do not lose it. I grab one thing from my bag.
The power button is better. It is on the front. It does not turn on by accident. My battery lasts longer. The tool feels strong. It has thick rubber. It feels like a pro tool.
Detailed Comparison for Klein ET300 vs ET310
I used both tools a lot. I can tell you how they compare. The specs look the same. But using them feels different. Here are the main points.
Design and Feel
The shape of a tool matters. I checked how they feel. I checked how easy they are to hold. The ET300 is straight. The ET310 is bent.
The ET310 wins. The bent tip helps. I can keep the sensor flat. My hand stays out of the way. The ET300 is straight. I have to twist my wrist. Also, the ET310 holds its own plug. This is smart. I do not lose pieces.
| Feature | Klein ET300 | Klein ET310 |
| Tip Shape | Straight | Bent |
| Storage | Loose Parts | Snaps Together |
| Switch | Side Slide | Front Button |
| Grip | Boxy | Smooth |
| Balance | Top Heavy | Even |
The Plug Part
The wall plug is key. I looked at what it does. I checked what it tells me.
The ET300 plug is simple. It just sends a tone. It has one light. It tells you nothing else. The ET310 plug is a tester. It has three lights. It shows bad wiring. It shows open grounds. It has a test button too. This saves me a trip.
| Feature | Klein ET300 | Klein ET310 |
| Sends Tone | Yes | Yes |
| Checks Wire | No | Yes |
| Test Button | No | Yes |
| Lights | One Light | Three Lights |
| Size | Small | Medium |
Speed and Truth
This is the big test. Does it find the breaker? I tested both on the same box.
Both tools scan twice. But the ET310 is better. The ET300 beeps too much. It beeps at the wrong switch. I have to guess. The ET310 is sharp. It picks just one switch. It makes a clear sound. It is faster to use.
| Feature | Klein ET300 | Klein ET310 |
| First Scan | Noisy | Noisy |
| Second Scan | Okay | Great |
| Wrong Beeps | Many | Few |
| Sound | Loud | Clear |
| Trust | Okay | High |
Battery Life
Dead tools are bad. I checked the power. I checked how they last in a bag.
The ET300 dies fast. The switch bumps on. I open my bag and it is dead. The ET310 is safe. The button is flat. It stays off. Both use a 9V battery. They last the same if you are careful. But the ET310 is safer to carry.
| Feature | Klein ET300 | Klein ET310 |
| Battery | 9V | 9V |
| Switch Spot | Side | Front |
| Turns on in Bag | Yes | No |
| Battery Door | Screw | Screw |
| Life | Good | Good |
Cost and Value
Is the new one worth it? Prices change. But they are close. I looked at what you get.
The ET300 is cheaper. But not by much. The ET310 costs a few bucks more. For that money, you get a lot. You get the wire tester. You get the clip storage. It is a better deal. Buying the old one saves pennies. But you lose features.
| Feature | Klein ET300 | Klein ET310 |
| Price | Low | A bit more |
| Tools in Box | Finder | Finder + Tester |
| Need More? | Yes | No |
| Warranty | Same | Same |
| Best Buy | No | Yes |
Conclusion
I tested both tools. The choice is easy. The Klein ET310 is the best. It tests your outlets. It clips together. It is easier to hold. The ET300 is old now. The loose parts are a pain. The switch is bad. Spend the extra money. Get the ET310. It works better.