Dielectric Union vs Brass – When and How to use both fittings

There are a lot of repair work around the house that deals with fixing the piping system, and sometimes, you might opt for doing it yourself. The challenge is how do you get to know the right fitting to use for a particular piping system? This dielectric union vs brass will let you know the right fitting for you to use for any piping system operation.

Knowing your tools and how to use them can be the defining moment to becoming a successful plumber. Also, you might get the wrong outcome if you use the wrong fitting.

So, let’s check out the differences and all that you need to know to identify and choose the right one for whatever plumbing work you have at hand.

What is A Dielectric Union?

Knowing what a dielectric union is will help you know where and when to use it. It is a special adapter otherwise known as fitting, which is common in a piping system. It is basically used for connecting dissimilar metals.

If you are connecting a copper pipe to a galvanized iron pipe, you need a dielectric union because the two must not come in contact with each other as the tendency to get rush is high due to electrolyte breakdown.

Dissimilar metals get to easily get rust whenever they come in contact with one another. Although it looks almost impossible to stop corrosion or rust from taking place, the use of the Dielectric union will prolong the process of corrosion.

What is Brass?

Brass fittings and nipples are also great alternatives to dielectric unions for water distribution systems. The brass fitting can be used to prevent corrosion and rust in a piping system.

However, it is mainly used where poor water quality is present and galvanized material has a higher tendency of getting corroded.

Dielectric Unions vs Brass : What’s the difference between Dielectric Unions and Brass ?

The brass fitting is an alternative to the use of dielectric unions for piping installation. However, there is more to the difference between the two fittings, and here we have the differences for you so you can find it easy to identify and choose the right one for any plumbing task you’ve got.

Build up

A dielectric union is a fitting or adapter that is designed to be used in the piping systems of different metals or dissimilar metals to avoid corrosion and rust. The design integrates an elastomeric rubber gasket that helps to seal the connection between the two metals.

The primary aim of this is to help prevent leaking of any sort, which could occur as a result of rust or corrosion. Dielectric union is undoubtedly approved for use throughout water distribution and piping systems, and also, it as an alternative in brass which can be used in the absence of dielectric union with some other materials.

Uses of dielectric union

In any piping system, whenever two dissimilar metals come together, there is a higher tendency to experience rust or corrosion. Either of the two mentioned can lead to leaking, which could affect the building of an apartment.

Any corrosion that occurs as a result of the contact between two metals is known as galvanic corrosion. However, to prevent such, one needs to make use of the dielectric union.

It is best for connecting two metal pipes as it performs great work to lower the chance of rust and corrosion quickly. Also, one can make use of brass as an alternative but only with copper pipes and when dealing with poor water quality.


Dielectric unions are used in the residential and commercial water distribution system. The reason for this is that it has the tendency of reducing the chance for electrolysis buildup and deterioration in the piping systems.

The plastic composite material behind the union’s clamping collar helps in breaking any electrical continuity between the two systems, thereby limiting the chance for corrosion.

Dielectric Union

A dielectric union is known to be threaded steel that is being used to connect copper pipes using different materials, mostly galvanized steel pipe. When connecting an iron pipe to a copper pipe, a dielectric union is a perfect option as it is best for joining two dissimilar metal pipes together.

Also, a dielectric union is mostly used in the commercial and residential water distribution center to avoid deterioration and electrolysis in the piping system.


It is a malleable alloy of zinc and copper that is being used as an alternative to a dielectric union in a piping system. It is perfect for where poor water quality is in use as it has the tendency of causing corrosion and rust very fast. Also, for any brass and copper pipe connection, a brass fitting is the right choice.

Is brass a dielectric union?

Brass is an alternative to a dielectric union. However, if your water piping and connections are copper or brass you can go on with the use of brass in the absence of a dielectric union.

But if you are connecting copper to a steel pipe, brass is never the right option for you.

Do brass and copper react?

Brass and copper don’t react with each other, and to ensure reaction doesn’t take place, and one needs to have a threaded female end on both the copper and steel pipes and connect the two with a short-threaded brass nipple.

Do dielectric union leaks?

Well, the primary aim of using dielectric union is to prolong the corrosion or rust process, and that doesn’t mean rust will never take place. One might experience leaking from the dielectric union due to rust as a result of the years of usage. So, leakages can occur with a dielectric union.

Can you reuse dielectric union?

It is not the right thing to reuse a dielectric union. Such an act is not good for any piping system as the dielectric union might already have a defect that is unknown to you and that can affect the condition of your piping system.

Final Words

You’ve got to know when to use dielectric union and brass in your piping system. This post on dielectric union vs brass thus opens your eyes to important things with the two fittings.

They are unique in their design and operations, and that is the reason you need to identify each to help you know when and how to use them in any piping system.