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What Are Ferrule Crimpers Used For? Guide with pictures

If I hadn’t been an auto technician, I think I’d have been an electrician, I really like wiring projects. In the workshop, I’m the go to guy for auto electrical problem solving. You are in the right place and a few moments from now, you’ll be well on your way to using ferrules like a pro.

A ferrule crimper is a hand held tool used to crimp (attach) ferrule terminals to striped wire. Ferrule terminals are fitted to wire in order to protect the loose strands from damage which may be cause when fastening to block terminals.

In this post you’ll learn what a ferrule crimper is, what its used for. You’ll also learn how to use it and I’ll recommend a great ferrule crimper for occasional use that won’t break the bank.

What Is A Ferrule?

Ferrule crimps

A ferrule is a terminal that’s fitted to stripped stranded and non stranded wire. They are used mostly in industrial panel systems. But you’ll have come across them in the home and on automotive accessories. If you’ve added an accessary to you car, boat, RV or whatever, you’ll probably have benefited from ferrule terminals.

Damaged wire
Broken wire strands caused by block connector clamp

The ferrule prevents loose copper strands from breaking and also eliminates wire splaying as the block connector terminal screw is tightened. Fitting wiring direct, without the ferrule, to a panel or block connector is of course possible, but it’s a pain in the jacksie.

With the ferrule fitted to the wire you can easily fit the wire blind into a block connector, no catching or fraying. And when the clamping screw is tightened, you get a tight secure connection unlike loose wire that breaks as you tighten and so never really feels tight.

Loose and broken connections are the root cause of many electrical gremlins. The ferrule reduces resistance and as it remains tight, it’s excellent for automotive accessories where vibration can break or shake stranded wire connectors loose.

Ok, I think I sold you on the benefits of the ferrule, but not so fast, you’ll need a tool to fit them and that’s what we’ll cover next.

What Is A Ferrule Crimper?

Ferrule crimp tool

A ferrule crimper is a hand held tool that’s used to attach a ferrule to stripped wire, both stranded and solid. The crimper tool crush’s the ferrule sleeve, after of course the stripped wire has been inserted.

There are a ton of different type terminals, ferrules are just one type. However, ferrules are a little different in that most other terminals may be fitted using a single type crimping tool.

Owning a ferrule crimper tool is useful no doubt, but it won’t help when fitting a regular spade terminal, you’ll need a different type crimping tool for that job. The ferrule crimper is designed to suite the ferrule terminal only, it can’t be used to fit other profile terminals.

Next we’ll cover how to use the ferrule crimper tool.

How To Use A Ferrule Crimper Tool

Crimped wire

Using a ferrule crimper tool is really easy. But like all tasks, it requires a little prep work, get that correct and the crimping job will move like butter.

Wire is measured by the American Wire Gauge (AWG) standard. The lower the number the larger the wire. We need to know the size of the wire we are working with because it corresponds to the size of ferrule terminal we’ll fit.

Now, this isn’t a problem if you have an assortment of ferrules to hand, you can run a Cinderella test. But if you’re ordering ferrules, you’ll need to match your ferrule gauge with your wiring gauge.

If you need to check your wire size, check out this web site (, it lays out all wire sizes, but you’ll likely need a Vernier calipers to measure your wire size.

The whole process looks like this:

Strip wire
Prepare wire by stripping it
Crimp in tool
Fit ferrule in the tool
Crimp tool in action
Hold the wire securely while squeezing the handles
Checking crimp is secure
Crimped terminal
Ferrule crimp V’s bare wire

That’s it, you’re a Pro!

Ferrule Crimper I Recommend For Occasional Use

Crimpers can be expensive, like $200 or more expensive, and sure if you crimp a lot then you need an expensive set. But the truth is, most of us need a crimper for simple running repairs, or to fit an accessory, I suppose you’d call us “The occasional user”.

All that said, I picked this tool because I don’t do a ton of ferrule crimping work, my work is mostly fault finding and soldering repairs. If I fitted lots of auto accessories then yes I’d likely spend more money. I’m more than an occasional user and it’s more than enough ferrule crimper for my work.

Wiring a tow bar

Ok, so how did it perform? The Wieprima performed well, it’s not as smooth as a Knipex, but it’s not Knipex money, it’s a fraction of the price, and the results are pretty good. I genuinely couldn’t find fault.

The Wieprima has a ratcheting handle which makes for comfortable crimping, I have a regular set of crimpers where you must make the crimp in one action, they work great. But if you have ten or more crimps to make, your hand gets tired.

Adjusting the crimp
Adjusting the handle

The Wieprima crimper can handle gauge 23 (smallest) right up to gauge 7, although you’ll need to adjust the ratchet (simple task). This set comes complete with a 1200 piece selection of ferrule crimps, I’ve not used every type yet, but I’ve used lots of the 16 and 14 gauge and had no issues.

You can check out the cost and delivery of Wieprima ferrule crimping kit here on