I am using the crimpers on the insides of the handles of this tool to crimp these spade connectors to 12 AWG wall wire and it is failing completely. After vigorous crimping, including manually bending where the wire is sheathed with the connector, the connectors can still be easily pulled off (if they don't just fall off) and are not making a good, high surface connection. Some of these will be handling 240V 20A current. I can use any kind of male/female wire-to-wire connectors, but I need female spade connectors to connect some of the wiring to male spade terminals on a current detector and relay. Can anyone recommend a good way for me to make strong, high-surface contact wire to female spade connections? Thanks.

 

I have never used that crimping tool but... First make sure you are using the properly sized spade terminal. Strip back the wire and insert it into the connect. Look down into the wire socket from the spade end and make sure you see that the bare conductor is fully into the connector. One trick I always do is look at your crimper and orient it so the anvil (the male part sticking up) is on the spade side of the terminal. The way the terminals are formed the metal is rolled up around forming the round area to accept the wire. The seam is on the top (away from the spade). If the anvil side of the crimper is used slightly off center from the seam it can cause a poor crimp. Crimping with the seam part of the terminal in the saddle part of your crimping tool takes care of the problem.

 

My guess is that it might be a material problem. There are a number of 1-star reviews of those spades describing the same failure you're experiencing.

Perhaps try out a brand name connector like Ideal/Buchanen and see if those work better with your crimp tool.

 

It appears to be a combination of both. Ideal or TB crimps are all I use.
Those crimpers don't look like they apply a lot of pressure to the crimp either.
I would highly recommend a good crimper like the one in the picture. The compound action on the opposite side of the handle gives the crimp a solid bite on the wire.

Klein, T&B, Ideal all have the same type of crimper.

 

Most crimp connectors are not rated for solid wire and will have the problems you are describing so make sure you are using stranded.

 

X2 on the crimps not for solid wires .

 

I agree.
Solid wire can not be crimped!
If you need a terminal end you would crimp it onto stranded wire and then wire nut that to the solid wire.

 

The reviews were not very good either. Seems others had problems too.

 

Thanks for all your answers. It is solid wire. My big mistake; it's been quite difficult to run, too. I will do what GregH suggests (wire nut stranded to solid wire) as well as get a better crimping tool and better connectors.

EDIT: "My big mistake" was apparently because no one sells 12/2 or 12/3 stranded building wire.

 

Stranded wire is available but not usually found in box or hardware stores.

 

Stranded will be available as individual conductors .

 

You can get stranded #12 MC (metallic cable) which is a building cable. Stranded #12 is not available in NM (Romex) building cable.

 

Using stranded and getting a "real" crimping tool has resolved my problems. It crimps about 3/16" along the length of the connector with a lot of force, instead of the 1/16" length my original crimper did without much force. I'll be using Wago lever nuts instead of wire nuts for various reason, one of which is that I can easily unplug the wires as I try to keep the electrical box organized. I did buy some individual stranded wire. Fortunately I didn't have to buy overpriced rolls; a hardware store near me had them by the foot.