How to safely *temporarily* wire 120v?

Question

I am wondering if there is any device to safely create a wire connection?

More specifically, here is my most recent situation: troubleshooting a noisy 120V electric motor (fireplace blower). The motor had a proprietary 2-wire plug which connected to the fireplace wiring, but using that wasn't an option when I was in the garage trying to give it power. I ended up hooking up two small alligator clips to the two prongs inside the connector and then hooking the other end of the alligator clips to an electrical cord which I had cut open and exposed the two wire ends. I would plug the electrical cord into my power strip, switch on the power strip, and run the motor. The alligator clips just hanging of loose wiring made me nervous, and indeed at one point I somehow bumped the assembly, the wires touched and boom I flipped the circuit breaker and was in the darkness. Ugh. Trying to figure out if I can do something a bit more foolproof next time...

My approach seems great for automotive 12V, but doing the same 'just use some nails/twist the wires together' seems like a bad idea with 120V!

I saw something of this sort on amazon:

I am thinking that could be an easy way to connect wires together. This device could permanently sit on my power cord and I could plug raw wires from whatever I'm testing into it?

Answer 1

These connectors are designed for quickly and safely connecting power to a unterminated mains cable for testing purposes -

This example has a datasheet available here

Power is only applied once the cover has been closed.

Answer 2

These are usually Chinese copies of the well known Wago brand, of dubious quality, dropshipped from China via Amazon. I've never used these particular ones, but I don't like the original Wagos of the same shape because the levers are way too tight and hard to handle.

I'd recommend getting genuine Wago 221 instead. It's the newer version, smaller and much easier to open and close. They're very good, I have a box on my bench that I use for temporary connection all the time, and they never seem to wear out. Unlike wire nuts, they don't destroy the wire you put in, and they work very well both on stranded and solid core wires. They're supposed to be used for electrical installations, for example for lights, where you want to be able to disconnect it easily later... but they also work fine for much smaller wires, like the legs of a resistor, Cat5, etc. If your multimeter probe is long enough, it'll also fit in the clamp, which is pretty useful when you have only two hands and want a reliable probe connection to a wire while doing something else.

Answer 3

You could use those if they handle 120vAC or more.

Otherwise, wire nuts are the dead-simple standard in the US. You could but the. In a junction box enclosure if they are not going to be in the electrical enclosure of the fire place. https://www.lowes.com/pd/IDEAL-Assorted-WireTwist-25-Pack-Multi-Wire-Connectors/3128809?cm_mmc=shp-_-c-_-prd-_-elc-_-ggl-_-LIA_ELC_106_Tools-Wire-Connectors-_-3128809-_-0-_-0-_-0&ds_rl=1286981&ds_a_cid=112741100&gclid=Cj0KCQiA-qGNBhD3ARIsAO_o7ymdO9ZSYiU4SFMMijBvlQk03zIeTKry-nX8D69xfrCzHq9vh3wwiiAaAnEkEALw_wcB&gclsrc=aw.ds

Or you could grab a euro strip connector. Kind of like the orange connector you have except you screw the down with the set screw inside the strip with a small screw driver.

https://www.lowes.com/pd/Utilitech-Quick-Wire-Connectors/999953966?cm_mmc=shp-_-c-_-prd-_-elc-_-ggl-_-LIA_ELC_106_Tools-Wire-Connectors-_-999953966-_-0-_-0-_-0&ds_rl=1286981&ds_a_cid=112741100&gclid=Cj0KCQiA-qGNBhD3ARIsAO_o7yldqmjH0Yz1ctMH8BZdxtMTVk6SzGGoaQhINtmYmH-xSiH8ufqgSX0aAgmtEALw_wcB&gclsrc=aw.ds

Answer 4

The criteria for a safe connector should include:

• Insulated and protects users from accidental contact with voltage
• Designed to prevent wires with different potentials from making contact with each other
• Connector is designed for the voltage and current in use
• Retains wires with sufficient force to prevent them being pulled out
• Easy to verify connectivity is being made

Some connectors are designed for one-time use, others (like the lever-nut style you show in the question) are designed for multiple use. The popular "wire nut" common in the US I feel fails on several of these criteria, and it its questionable whether they satisfy the multiple-use condition.

It is off-topic here to ask for specific product or manufacturer recommendations. That said, you can certainly look for similar types of connectors. Here are some keywords which you may find useful:

• Reusable splice connector
• Spring (or spring lever) terminal connector

There's also something called a "Cliff Quicktest" which is featured, for example, on Big Clive's Youtube channel. It allows connection of devices to mains voltage in a safe manner. He provides links to various suppliers, but I'll just link the video and you can find competing or comparable products as you like.

Answer 5

Smells like you're searching trouble. What if the device under test (=DUT)leaks the mains AC to its surface. Where's your 3rd wire (=protective earth) and ground fault interrupter?

You caused a blackout with the clips. What, if the DUT alone has a short circuit? I believe you'd be glad if your test bench had a local fast acting circuit breaker which hopefully trips before the mains AC is cut by the breakers in the distribution cabinet of your house.

A proper test bench should also have a switch and an indicator lamp which shows that there's voltage ON. Even better would be a case around the connector with forced 2 pole switch which separates DUT as soon as the case is opened.

You should prepare there a place to measure the current safely (= no movable measuring cords)

Prepare to see the day when someone pulls one of your powered cords without a warning. It can be also you. Hopefully that causes nothing - if you are prepared.

A slightest spill of water would meet the voltage if you have the connector as you planned at the end of an extension power cord. The risk may be quite low in the middle of Sahara, but in rooms where people work and live the situation is totally different.