Learn how to install an electric float?

Do you know what an electric float is and how to install an electric float? The electric float is a device that has the purpose of controlling and indicating the fluid level in a given reservoir, activating or disconnecting the supply system.

What is an electric buoy?

In a way, we can say that the electric float is an “automatic switch”, because when it is detected that the liquid level is low, a command is sent and then the pump is activated, but when the situation is reversed, the float electrical disconnects the circuit instantly, that is, it is not necessary to go to a switch to effect the system shutdown, however, it is with the installation of the float that this whole system is automated.

The electric float is very common in civil works and with an enormous facility for installation. The electric buoy, which is also known as the electro buoy, is widely used in wells, tanks, boxes, fountains, fountains, bilge pumps, among others, whether in a residential, commercial or industrial project, in these cases the presence of the buoy is indispensable.

The function of the electro buoy is to protect and control the pump, for example when a water tank is empty, the circuit is spontaneously activated and the engine starts to pump the liquid from the cistern to the box until the desired level is reached, that is, as soon as the water tank is full, the system is turned off. Below is an illustration of an electric float


Electric float for control and level indication in liquids.

How to connect the electric float?

The first step that we must emphasize is that the cables of the float will be in direct contact with the water, that is, it is essential that they are well insulated. It is recommended that you first insulate the electrical cables with self-fusing tape and then with the insulating tape, to ensure that there is no moisture and the electrical cables do not oxidize or cause a short circuit, which could cause serious damage.

Before making any connection is essential to check the power correct the float that you will use, as it will be possible to measure which machine is recommended, ie a buoy with 15 amp current bear one engine 3 / 4cv in 127V or similar of 1hp at 220V. Generally, all of these specifications are present in the manufacturer’s manual.

Which call should I make?

Direct connection is an option for motor and pump connections, however, this type of connection is only suggested for single-phase motors 1/8, 1/6 /, 1/4, 1/3, and 1/2. For higher power motors it is not recommended to use this type of connection.

The counterweight is essential for the proper functioning of the entire circuit, a hole must be drilled in the desired container and thus adjust the counterweight as desired. The greater the distance from the float to the counterweight, the lower the minimum level for activating the electro buoy and the closer the counterweight to the electro buoy is adjusted, the minimum level increases (this varies according to the consumer’s need). The figure below shows the installation of the counterweight in the reservoir.

Layout of the counterweight in a reservoir.

Generally, a contractor or relay is used to make this connection, since the buoys may contain two or three cables, NF (Normally closed), NA (Normally open) or NF + NA. To activate the system, one of the pump cables is connected to the electrical network, while the second cable goes to the contractor, the contactor is parallel to the lower float and another contactor cable is connected to the upper float, in turn the other end of the upper float is connected to the other pole of the electrical network.

For example, when the upper fluid level drops, the lower float closes the contact, feeding the contactor; the contact keeps energized until the level of the upper box reaches the upper float, at the moment when the level is reached, the key opens again, disconnecting the set.

Simple buoy layout

There are several names for this device, float switch, automatic float and electric float, all with a single purpose. Merchants have a wide variety of models, but the most common are those that work through contact with mercury.

In addition to the device previously presented, there is another common good that is the level sensor, in which it detects the level through the movement of the floats, which produce a magnetic signal, sent to the sensor. The following video is explanatory and will present the differences, advantages and disadvantages of each of the instruments.