Installing a gas boiler will help solve the issue of heating, warm water and optimizing the internal microclimate in the housing at its discretion. But in order to avoid breakdowns and level the risk of gas fire, the installation and further operation of such a powerful electrical device must be performed in compliance with all rules. Do you agree?
We will tell how to make the grounding for the gas boiler in accordance with building codes and recommendations of the EMP. In the article proposed by us, the assembly technology was analyzed in detail. Our advice on the choice of material and the implementation of preliminary calculations will allow the equipment to be properly grounded.
The content of the article:
- Why do you need to ground the gas boiler?
Contour device subtleties
- What material to choose for earthing?
- Contour parameters calculation
Installation of the grounding system for the boiler
- Design and preparatory work
- Install and connect the circuit
- How to check the work and get a certificate for grounding?
- Conclusions and useful video on the topic
Why do you need to ground the gas boiler?
A mandatory element of the device of any gas boiler is a metal casing, on the surface of which static charges are formed when the device is connected to the network.
And if you do not take care of the "ways of waste" for electricity, in one unfavorable moment, the entire electronic component of the device or its individual elements can fail. For example, a board or control system.
To prevent this from happening, the boiler is “secured” with a grounding conductor that connects the appliance to the grounding plane, and the latter - directly to the ground. The earth has the property of “absorbing” electric current, therefore its environment will be a guarantee of safety from equipment failure when voltage drops or short circuits in the network.
Whatever type of boiler you choose - gas, solid fuel, electric - the correct installation of the equipment is impossible without the construction of a grounding circuit
Grounding is necessary to:
- Reduce the explosion hazard of the device - static electricity is often the cause of spontaneous combustion devices operating on gas, and even under pressure.
- Eliminate the possibility of injury - the metal case sometimes “pierces”, and when touched a person can feel the electric shock from a light tingling to a powerful charge followed by a lethal outcome.
- Warn automatic breakage - gas boiler boards are sensitive to voltage fluctuations, and their replacement will cost at least a third of the cost of the equipment itself.
In addition, there will be a lot of questions from gas service inspectors to a boiler operating without grounding, which can lead to tangible penalties and forced shutdown of the device. Therefore, it is worthwhile to equip the grounding loop in any case, because it is not only about economic nuances, but also your safety.
Contour device subtleties
The grounding system can be natural or artificial. The first option includes structures made of metal or reinforced concrete, which are in direct contact with the ground. It may be a building foundation, a pipeline or other underground utilities.
But for gas boiler natural grounding requires at least two contacts with separate parts of the housing, and in this case pipes for sewage, heating and gas pipelines are excluded. Therefore, the installation often uses an artificial system, the organization of which we consider.
What material to choose for earthing?
For artificial grounding, conductors-electrodes become rods or pipes, which are interconnected by metal strips. They are installed vertically in the ground to ensure system operation even in the winter season, when the upper layer of the earth freezes.
An important condition is that metal elements should not be protected from corrosion by an insulating material.
The service life of the grounding circuit depends largely on the presence of anti-corrosion protection on its electrodes - copper and stainless elements will last the longest
Ready-made kits for the earthing system, which consist of steel rods (usually with copper coating) and special pointed tips for the soil of different density.
The kit also includes anti-corrosion agent for processing the system before installation and connecting elements - brass couplings, clips. The main advantage of this solution is that the circuit can be assembled without welding and long preparation.
Although the controlling services advocate for ready-made kits for grounding, it is feasible to make the construction independently - it will not be a violation, but it will be much cheaper
To build a system from scrap materials, you should consider several important nuances:
- The metalwork intended for installation in soil can be made of a profile pipe, an I-beam, a channel, a corner.
- The earthing metal must be protected from damage by galvanizing, copper coating or, in extreme cases, anti-corrosion paste.
- The cross-sectional area of the wire connecting the zero phase of the shield with the grounding circuit depends on the type of metal from which it is made. For copper, the optimal value is 1 cm2, for steel - 7.5 cm2, and for aluminum - 16 cm2.
- Grounding resistance for sandy ground should not exceed 50 ohms, for clay soil - a maximum of 10 ohms.
- Materials for the electrodes should be selected and taking into account the resistance of the circuit. The best option is two-inch pipes or corners with a length of 2 m and a cross-sectional area of 5 cm2.
- Ground bus is made of copper or steel strip (aluminum for this case is prohibited to use).
Compliance with these requirements and properly executed ground loop installation will help eliminate claims from gas inspectors regardless of whether you used a ready-made modular system or assembled it yourself.
Contour parameters calculation
There are several indicators in the list of requirements for the grounding arrangement, the algorithm for obtaining which may be incomprehensible to a beginner in electricians - for example, how many electrodes will be required for the system to work properly or how to measure the resistance contour. Let's try to clarify the basic principles for determining these parameters.
It is possible to find out the resistivity of the soil, grounding devices of any configuration and even the presence of a connection between the electrodes using a special meter
Grounding is done after gas boiler installation in a country house. The physical parameters of the grounding circuit are selected mainly by experiment. Such a practical way is suitable for those who are afraid of getting bogged down in complex theoretical calculations.
The algorithm for doing this is:
- Let's take as a basis a contour in the form of an isosceles triangle of three metal rods 3 meters long.
- We connect the conductors.
- Take an ohmmeter (a device for measuring resistance) and measure indicators for the circuit. The ideal value is 4 ohms.
- If the result obtained significantly exceeds the optimal indicator, we add one more element to the contour, again we check the resistance. We continue until we get an ideal indicator or at least the maximum permissible value for the boiler circuit 10 ohms.
But you can determine the required number of electrodes using formulas by selecting the appropriate options for your case.
According to this formula, it is possible to determine the resistance for a single electrode, if on the site where the house is located, the ground is homogeneous and does not form layers
In the formula you need to substitute the average value of the resistivity, depending on the type of soil in which the earthing switch will be located:
- wet sand - 500 ohm * m;
- clay gravel and sandy loam - 300 ohm * m;
- clay-sand mixture - 150 Ohm * m;
- loam - 100 ohm * m;
- semi-solid clay and black earth - 60 Ohm * m;
- garden land - 40 ohm * m;
- plastic loam - 30 ohm * m;
- peat - 25 ohm * m;
- plastic clay and saline - 20 ohm * m.
The least suitable for installing grounding circuit stone and rocky soil. In this case, it is necessary to build an artificial mound.
For heterogeneous soil, it will be more difficult to calculate the resistance for a single electrode, but even this can be done by substituting your data in the indicated formula
The value of the seasonal climatic coefficient of soil resistance depends on the area where your house is located. Conventionally, they are divided into 4 groups.
The correction for climatic conditions is especially important for areas with cold winters, since grounding efficiency is significantly reduced in frozen ground.
There are also more complex algorithms for accurate determination of electrode parameters and even special programs for calculating them. But for the gas boiler to work correctly, it will be enough to follow the general recommendations for arranging a standard ground loop.
Installation of the grounding system for the boiler
To install the contour, you will need to allocate free space, which is at a distance no closer than one, but no more than 5 meters from the house foundation.
This site can no longer be used for the construction of various extensions, planting, and in general, it is not safe for a person to be on it, because if triggered, it can end in death the outcome. Therefore, it is worthwhile to fence the contour with a border and ennoble a place with some kind of stone composition or decorate with garden sculpture.
Design and preparatory work
To ground the gas boiler, first, a layout of the future contour is drawn on a dedicated area. The most commonly used scheme involves the placement of grounding on the sides of an isosceles triangle.
But the contour may be in the form of a line, a square or a polygon - it all depends on the calculated number of electrodes and the location of the building itself.
Although traditionally, when arranging the contour, an isosceles triangle with sides of 0.5-2.5 m is selected, with a shortage of free space near the house, the system can also be linear
To assemble a self-made design, you will need the following tools:
- welding machine to connect the metal elements of the system;
- grinder for cutting and sharpening pipes or rods;
- perforator or drill for plant grounding cable to the house.
And also need to prepare a tool for digging. The minimum set, which probably will be found in stock at the owners of a private house - a bayonet spade and a heavy sledgehammer. But if there is solid ground on the site, it is better to get a hole or a motor drill, which will greatly facilitate the “deep” stage of work.
Install and connect the circuit
Now let's consider step by step how to make a triangular contour for grounding a gas boiler. First you need to dig trenches along the lines of a pre-drawn layout. The optimum width of each groove is 35-40 cm, depth - 50-70 cm. From the top of the triangle nearest to the house, a straight trench to the foundation is held.
The triangular scheme is simple and reliable, because even if the metal bridge between the rods is damaged, it will continue to function from the other side.
With the help of a sledgehammer or a hole on the vertices of the triangle electrodes are vertically hammered - steel conductors from pipes or corners. To facilitate this process, you can sharpen the lower edge of each segment with a grinder.
They must be installed at such a depth that the distance from the bottom of the trench to the upper edge of the conductor it was in the range of 15-20 cm (that is, subsequently the whole structure will be covered with a layer of soil of 30-55 cm).
Next, the electrodes must be connected to each other. Lay a steel conductor with a cross section of 4.8-5 cm2 or a strip 4 cm wide and at least 4 mm thick over trenches dug along the sides of the triangle. Prefabricated grounding kits can be bolted into the kit. And for homemade designs the best way out is spot welding.
An illustrative diagram of the grounding loop for a gas boiler, for the manufacture of which steel strips and three electrodes were used
Then it is necessary to weld a horizontal metal strip to the steel conductor, which will be brought along the trench to the planned location for entering the grounding into the building itself. It rises above the blind area approximately 50 cm (a steel pin can also be used).
Now you need to start grounding the house. To do this, a hole is made through the perforator in the wall through which the copper wire is passed. M8 bolt is welded to the strip. Copper wire is fixed at one end to the terminal on the grounding bus, and the second - to the metal plate on the base.
Connection diagram through a three-core wire to the circuit and the power transmission line column (to arrange such a connection, it is necessary to obtain permission from local power grids)
Then the gas boiler is connected to the panel through an individual circuit breaker using a three-core wire. Additionally, it is recommended to install a voltage regulator.
How to check the work and get a certificate for grounding?
Using a measuring device, determine the resistance of the current spreading around the circuit. If the result measuring grounding resistance does not exceed the maximum permissible figure of 10 ohms, then you can bury trenches.
If deviations were found - add the required number of electrodes, make sure that the resistance is normal. Grounding is ready, you can bury the circuit and call the inspection.
To bury trenches with earthing, use only homogeneous soil, without admixture of stones and construction debris, and close the place of entry of the system into the house from the precipitation with a PVC box
By the way, there is another way to check the health of the system. To do this, you need a simple light bulb with a power of 100 W (or more), which is screwed into the cartridge with a carry. Then one end of the carrying is connected to one of the horizontal strips of steel installed on the sides of the grounding triangle, and the other to the phase of 220 volts.
Compare the result:
- The lamp burns brightly, as if plugged into an outlet — the circuit is working.
- The lamp is on, but the light is dim or blinking - boil again the design joints.
- The lamp does not burn - you need to check the integrity of the entire scheme, starting from the quality of welding to the supply of the shield.
Representatives of regulatory bodies are usually guided in verifying the readiness of equipment for operation by the recommendations of the EMP specified in paragraphs 1.7-1.8. They determine the resistance of the soil and the grounding circuit, the correctness of the connection to the shield of the gas boiler and other options.
Without an act and verification protocol from the gas service may refuse to connect your house to the gas pipeline
If all indicators are normal, a grounding certificate is issued. It is a set of technical documentation from the test report with the list of applied measuring instruments, laboratory registration certificates, circuit verification protocol between the ground loop and the boiler, defective list.
With features of the bath grounding in the apartment of a multi-storey building will acquaint next articlewhich we advise to read.
Conclusions and useful video on the topic
And finally, we offer a selection of video materials, where you can get a clear idea of how to safely ground the gas boiler in a private house.
In this video you can see the construction of the grounding circuit of 4 rods with the task to achieve resistance up to 7 Ohms:
Another option for the arrangement of the contour of the gas boiler for a private house connected from the post:
The grounding system is an important step that should not be neglected when installing a gas boiler. And if you are not sure that you can correctly install and connect the circuit to the panel, it is better not to risk and turn to builders, because not only the safety of expensive equipment is at stake, but the most important thing is your safety and even life.
Tell us about how you built the grounding system in your suburban area. It is possible that you have information that will be useful to future independent installers of grounding systems. Please write comments, post photos on the topic and ask questions in the box below.