Skip to content
Home >> Plumbing >> Pipes >> Fittings >> When Are Dielectric Fittings Required- Is It Necessary?

When Are Dielectric Fittings Required- Is It Necessary?

A safe plumbing connection is required to maintain the longevity of the pipes. Likewise, plumbers usually opt for dielectric fittings for maintaining multiple metallic connections throughout the house.

Now, when are dielectric fittings required? They are generally required in water pipelines to connect two different metallic pipes. And also while installing a water heater. Well, these fittings prevent early damage and corrosion between the different metal pipes.

when are dielectric fittings required

Now, when to use dielectric fittings? How do they work? We’ll discuss all these below. From there, you will be able to know the necessity of using the union and its function in the pipeline assembly. So let’s dig in!

When Are Dielectric Fittings Required?

Dielectric fittings are connectors that connect two different pipes. They are mainly used between pipes made of different metals. Well, these fittings are mostly found in water pipelines.

  • When pipes of different metals, such as iron and copper, are connected, the union is placed between them. So, the corrosion that takes place between those two metallic pipes is reduced. And thus, the pipes are protected from being damaged and also last for a longer time.
  • They are also used in gas lines to serve the same purpose. But other suitable connectors are less hazardous to use in the gas line.

You can follow the YouTube video below to learn more about the dielectric union in plumbing systems.

What Do Dielectric Fittings Do?

Dielectric fittings are required between two different pipes to build a link between them. Thus, a safe connection in the pipeline occurs without any corrosion and without causing damage to the pipe.

Well, direct contact between the pipes causes corrosion and damage to both pipes. Generally, water is slightly acidic. When two metal pipes come into contact in the presence of water or electrolyte, an electrochemical reaction occurs.

Due to the presence of an electrolyte, the metals react with each other during the reaction. The reaction results in depositing by-products of corrosion in one of the metals. Where the other gets decayed by transferring ions continuously. This is called galvanic corrosion.

And also, a slight current flow is observed. When dielectric fittings are used, the pipes are not directly attached. Because the gasket used inside the dielectric fitting works as a non-conductor between two pipes.

It doesn’t let the water conduct ions, and the ions do not get a free pass. This prevents corrosion and protects the pipes from damage.

Overall, the main motive for using the union is to prevent the electrochemical reaction from occurring. Which slowly decoys the metal pipes and causes leakage in the pipe.

Where Do You Put A Dielectric Union?

The dielectric union is put just between two pipes while linking them. Generally, different male and female connectors are used in the pipelines to connect multiple pipes.

In the case of two dissimilar metallic pipes, a dielectric union is connected on both ends of the pipe. The union has holes on both sides to connect the two pipes.

What Happens If You Don’t Use Dielectric Fittings?

Pipelines can become extremely sensitive due to the corrosion occurring in them. It also becomes a hassle if it requires frequent changes. Here, dielectric fittings help prevent damage to the pipelines. Otherwise, the following problems are caused by the absence of dielectric fittings.


Two different metals tend to transfer their molecules to each other in the presence of electrolytes and water. Where water is a universal solvent that dissolves any molecule and keeps the ions.

As a result, one metal loses its components, while the other metal gets byproducts deposited on it.

This creates corrosion between the two metallic substances. Similar cases occur in the pipelines as well. Consequently, the pipe gets damaged, and soon water leaks from it.

Copper has a generally more tendency for corrosion. That’s why there is a higher chance of copper pipes getting decoyed when linked with other metal pipes.

Formation of scale

Due to the deposition of byproducts from the reaction, the pipes can get clogged. This results in the formation of scale in the pipeline. This is also a sign that the pipelines are getting decoyed and will soon need to be changed.


The leak mainly occurs due to corrosion between two pipes. As one pipe gets decayed, it results in a leak on that pipe.

To fix the leak, one would need to completely change the pipe. This not only costs a hefty amount but can also become bothersome. Especially when the line is installed in the infrastructure of the home.

Hazardous water

When the dielectric fitting is not installed, the pipeline deteriorates. This decay causes the release of metallic substances in the water inside the pipe. So, the water fills with a metallic flavor.

Especially when copper gets into the water in excess amounts, it can become hazardous to health. And slowly, that water can cause bodily harm.


Let’s go through some of the frequently asked questions people commonly ask.

Q: Do I need to use a dielectric union between copper and brass?

No, copper and brass pipes are compatible with each other. They don’t require the use of dielectric unions at the connection point. Still, if you want, you can use it. But it’s not mandatory to use.

Q: Do I need to use a dielectric union between copper and stainless steel?

Yes, the connecting point of copper and stainless steel pipes requires a dielectric union between them. Otherwise, galvanic corrosion can occur, which would deteriorate the pipes over time.

Q: Do building codes permit using dielectric unions?

Yes, according to building codes, dielectric fittings should be installed, and they should be of the proper size. Several sizes of unions are available in the marketplace. But only the one suitable for the pipeline and building should be used.

Final Words

Overall, the building’s plumbing system is really sensitive, as any damage would partially affect the building. Also, damaged pipes require quick fixing, and in most cases, replacement is more suitable. Moreover, different connectors are needed to assemble the pipelines.

But when are dielectric fittings required? Especially while installing different metal pipes, using a dielectric union is a must. Otherwise, the pipe would decay faster, and you would need to replace it immediately. Otherwise, the fittings would be of no help.