Dielectric insert for gas: types of gas couplings and rules for their installation

Gas appliances connected to power supply are connected taking into account three criteria: reliability, safety for users and equipment, and long service life. In order for gas water heaters, boilers, convectors or stoves to work without interruption, a dielectric gas insert is used - a small polymer insulator mounted in a pipe.

If you decide to connect your gas equipment yourself, we recommend installing a dielectric. What it is for, what types it is divided into and how it is installed, you can find out from this article.

Appointment of the electrical insulating insert

First, let's find out what the insulating dielectric sleeve for gas is for and how it works.

The main function of a dielectric is to protect equipment from stray currents that can arise in a gas pipeline for various reasons. Is wandering current so dangerous and are there any ways to prevent it from occurring?

It occurs in the ground at the moment when an accident occurs on power lines, railways, tramways. Due to the difference in the characteristics of the conductors - earth and metal structures of gas lines, the current is transferred to the gas system.

The danger can also be posed by the actions of illiterate neighbors who are in no hurry to replace faulty electrical wiring or simply ground electrical appliances to pipes or batteries.

Here's what happens if stray currents "get" to your gas equipment:

• gas appliances, most of whose parts are made of conductive metal parts, become unusable and themselves become sources of danger;
• if an accidental spark occurs, there is a risk of fire, which becomes thousands of times more dangerous in a gas environment. A fire can provoke an explosion, but for an apartment building this is a real disaster;
• stray currents transmitted to appliances and pipes during thunderstorms or power outages can cause serious injury to the gas appliance user.

To preserve their health and foresee any risks, they use a dielectric coupling on the gas pipe.

Now the insertion of a dielectric insert into the pipe has become mandatory for everyone who installs gas equipment in a house or apartment, while the functions and characteristics of the equipment do not matter.

The installation of insulating inserts is regulated by law - in paragraph 6.4 SP 42-101-2003 it is said that immediately after the shut-off valve, a dielectric should be installed in order to exclude the presence of leakage currents, equalizing currents and a short to the body in the gas pipeline. True, there is a reservation there - the function of an insulating insert can also be performed by a flexible sleeve that does not conduct electric current.

Types of dielectric cutoffs

In everyday life, two types of dielectrics are used for gas hose or pipes: simple bushings resembling liners and threaded couplings. Let's consider how the inserts differ and choose the best solution for self-assembly.

Option # 1 - bushings

Let's say right away that for gas stove installations or column mounting you do not need bushings, as they have a slightly different purpose. The task is the same - to protect against stray currents.

But they are installed where there are flange connections and bolts are used. Simply put, bushings are used to electrically insulate flange fasteners.

Dielectric inserts are made of polyamide PA-6. They are distinguished by their resistance to external influences and a long service life.

Technical characteristics of gas bushings:

• frost resistance - withstand low temperatures down to -60 ° С;
• elasticity and a high degree of adhesion to metal elements;
• petrol and oil resistance at temperatures up to +120 ° С;
• the ability to withstand multiple alternating loads.

Products are marked by diameter in mm, for example, from M 8 to M 24. The diameters of suitable flanges, bolts, washers are indicated by the manufacturer in special tables. You can also specify the height of the collar and the length of the bushings there.

Option # 2 - couplings

Universal insulating inserts for gas pipes are connected by the coupling method, therefore, installers are often called so - couplings.

They differ in the type of thread, diameter, material of manufacture, external design, but they still perform the same function - they cut off the currents generated on gas pipe, from equipment.

The inserts are made in the factory according to GOST or TU. They are produced in special molds in an automatic way, using a screw extrusion of two materials: an insulating polymer and a metal for threaded pipes. Polymer material meets the requirements GOST 28157-89.

The products are designed for operation at an operating pressure of 0.6 MPa, the critical indicator is 1.2 MPa. The average working temperature is from -20 ° С to + 80 ° С.

By GOST 14202-69 gas inserts belong to group 4 (flammable gases) and are marked in yellow, but you can also find products with a black polyamide part on sale.

It is better to purchase products from well-known brands, rather than Chinese fakes, and choose products based on the following criteria:

• fire safety - threaded metal elements do not burn, and plastic ones do not support combustion;
• wear resistance and durability - high-quality parts are made of brass and have a 20-year service life;
• suitable specifications - resistance of at least 5 Ohm with a sharp increase in voltage to 1000 V.

The best place to install the coupling is between gas cock and flexible eyeliner.

The connection method is threaded, made by screwing the device onto the pipe. The fittings can have both external and internal threads.

Before buying a dielectric, it is necessary to clarify the diameter of the gas pipe, as well as choose a flexible hose that is suitable in size. Sometimes connection hoses are sold with the equipment, so be sure to check the package contents.

The gas isolator is permanently installed and does not require maintenance, but is constantly monitored by the gas service, which inspects the equipment annually.

The procedure for installing a dielectric on gas

Before any work on gas equipment or lines, it is necessary to turn off the valve to stop the flow of fuel and ensure safety. If a stove, column or boiler was used before, the burners must be left in working order so that the remaining gas burns out.

Then we proceed in order:

1. If the flexible hose is already attached to the pipe, use a wrench to carefully twist the nut. Fasteners that have been installed for a long time often "stick", so you can use two keys to be sure.
2. On the free end of the pipe, we wind a sealant - fum-tape and carefully tighten the connection, first by hand, and then with a key. We screw the sleeve or "barrel" to the limit, trying not to knock off the thread and not deform the dielectric body.
3. In the same way, we screw the nut of the flexible line onto the other end.
4. We make connection diagnostics in a safe way.

Soap solution for checking the tightness of joints is used not only by users of gas equipment, but also by employees of Gorgaz. Diagnostics is simple: soap foam is applied with a shaving brush or brush to the joints and observe what happens.

The appearance of bubbles, even small ones, indicates a lack of tightness - the coupling will have to be tightened. If there are no bubbles, the installation is correct and you can safely use the equipment.

It is forbidden to use an open flame - matches or lighters to check for gas leaks.

Step-by-step instruction:

We remind you that you cannot use gas equipment before the arrival of a gas service employee. He must verify, record the fact of installing the dielectric and give permission to operate the connected equipment.

And in the future, carry out all activities for connecting, replacing, and repairing gas equipment together with representatives of the service organization.

Conclusions and useful video on the topic

How the dielectric is installed in the crane in practice:

The sequence of connecting the column to the gas pipeline:

Now you know how to correctly and quickly install a dielectric gas insert on a pipe. The installation procedure can be carried out independently or by a specialist - in any case, the result will be your safety and serviceability of home gas equipment. If you still do not have a dielectric, we recommend installing it, and at the same time changing the gas hose, the service life of which is limited.

If you had to deal with the installation of a dielectric on a gas pipe, please share your experience with visitors to our site. Leave your comments, ask questions to specialists and participate in the discussion of the material. The communication block is located under the article.