PEX Expansion Vs Crimp

by Joost Nusselder | Updated on:  March 18, 2022
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PEX stands for cross-linked polyethylene. It is also known as XPE or XLPE. PEX expansion is considered as the modern and advanced choice for domestic water piping, hydronic radiant heating and cooling systems, insulation for high tension electrical cables, chemical transportation, and transportation of sewage and slurries. On the other hand, a crimp is a solderless electrical connector used for joining stranded wire together.
Both joints are different in preparation, working mechanism, necessary tools, advantages, and disadvantages. We have tried to focus on the difference between the PEX expansion and crimp joint in this article. Hope this will help you to make the right decision in the workplace.

PEX Expansion

You need neat and clean square-shaped pipes to make PEX expansion. You have to use the expander tool to expand the rings according to the instruction provided by the manufacturer. Proper maintenance and use of lubrication will help you to attain high-quality durable connections. On the other hand, improper expansion may lead to leakage shortening the lifespan of the pipe and tube – so, be careful.

Basic Working Mechanism of PEX Expansion

PEX has a special characteristic of expanding and contracting. At the initial point, the size of the pipes, tubes, and sleeve is enlarged for the convenience of fitting. When the plastic sleeve slides and joins on the connection point the PEX shrinks so that the fitting becomes tight.

How to Install PEX Tubing?

First of all, you have to determine the PEX length and then cut the PEX according to your requirement. Then add the expansion ring to the cut end of the PEX. After that lubricate the expansion head and place the fully closed expansion head into the tip of the PEX. By doing so, you can ensure proper rotation and contraction. Next press the trigger and hold it until the tip of the ring hits the back of the expander cone. You will notice that the head shifts slightly with each expansion. When the ring bottoms out depress the trigger and count to an extra 3-6 expansion so that it doesn’t shrink back to size quickly. Once the ring bottoms out, keep the trigger depressed and count an additional 3-6 expansions. Doing this will ensure that you have enough time to connect your fitting without it shrinking back to size too quickly. You should test the fitting after 24 hours. You should be aware of the temperature of the working place because the temperature has an important effect on the expansion. So, it also affects the fitting process.

Pros of PEX Expansion

High flexibility, durability, long coil lengths, and lighter weight along with good resistance to freezing damage as well as corrosion, pitting, and scaling made PEX popular among the plumbers. Since connecting a PEX system is easier to learn it is also popular among the newbies. Compared to copper and brass PEX is more durable. The flexibility offered by PEX minimizes connections by up to half in certain applications. So, PEX is also considered one of the fastest piping installation methods available.

Cons of PEX Expansion

Leaching BPA and other toxic chemicals, prone to pests, bacteria, and chemical attack, sensitivity to UV light, high temperature, and the possibility of water leakage are the main disadvantages of PEX expansion. Let me talk a little more about each point. There are 3 types of PEX named PEX A, PEX B, and PEX C. Type A and C are prone to leaching problems, only type B is considered safe. Since PEX is made of plastic material it is more likely to get damaged by pests and chemicals. Some pest control companies claim that it’s very susceptible to pest damage. Most of the PEX manufacturers suggest a limited amount of UV light exposure and some of the manufacturers suggest total darkness. It is important to note during the installation of the PEX. Since PEX is likely to get damaged by the high temperature you should not install PEX in areas where it will get exposed to recessed light or water heater. PEX doesn’t have antibacterial properties. Because the semi-permeable property of PEX liquid can enter the pipe and contamination will take place.


Crimp is much simpler than PEX fitting. You will understand its simplicity in the following paragraphs. Let’s go.

Basic Working Mechanism of Crimp

You have to insert the stripped end of the wire into the crimp connector, Then deform it by crimping around the wire tightly. You need a terminal, a wire, and a crimping tool (Crimping plier) to perform this process. Since crimp connection doesn’t allow any gap between the strands of wire it is very effective to resist rust formation by preventing the entry of both oxygen and moisture.

How to Make Crimping Joint?

The first step is purchasing a pex crimping tool. You can buy either a ratchet crimper or a manual crimper depending on your choice and budget. A ratchet crimper is easier to use than a manual crimper. Then choose a crimping die that is appropriate to the wire gauge you are using. So, it is important to determine the wire gauge. The red wire has a gauge ranging from 22-16, the blue wire has 16-14 gauge, and the yellow wire has 12-10 gauge. If the wire does not come with colored insulation you can check its packaging to find out the gauge. Then stripe the wire with the crimper and remove the insulator. After stripping several wires twist those together and insert this twisted wire into the connector. Placing the barrel of the connector into the appropriate slot of the crimper squeeze it. If you find that the connection is loose you can solder the joint between the connector and the wire. Finally, seal the connection with electrical tape.

Pros of Crimp

Crimp fittings are cheap, simple, and fast. Since crimp connection creates an air-tight seal between the cable and connector it is protected from environmental conditions such as moisture, sand, dust, and dirt.

Cons of Crimp

Crimp fitting has negligible con to mention. One con can be that you need specific tools for each type of terminal that may cost you more.

Final Word

Crimp fitting seems simpler to me than the PEX fitting. Also, the cons of the crimp fitting are less than the PEX expansion fitting. Depending on your necessity and circumstances you can apply both to make connections. The crucial part is to make the right decision in a certain situation. If you have thorough knowledge about both fitting and you are also aware of their differences making the right decision will be easier for you.

I'm Joost Nusselder, the founder of Tools Doctor, content marketer, and dad. I love trying out new equipment, and together with my team I've been creating in-depth blog articles since 2016 to help loyal readers with tools & crafting tips.