Fluorescent lamp wiring diagrams.
Connecting fluorescent lamps to the mains via a ballast device.
Only specially designed aquarium ballast systems should be used, as they are engineered to operate in high-humidity conditions. However, they must not come into contact with water under any circumstances. For example, moisture-proof plastic cuffs are installed at the ends of the electrical wires entering the lamp to protect the contacts from moisture. The diameter of the cuffs can vary, which must be taken into account when purchasing fluorescent lamps.
Usually, fluorescent lamps are connected to the mains via a ballast device (choke) and switched on using a starting device – a starter. The following types of starters exist: glow discharge, thermal, electromagnetic, thermomagnetic, and semiconductor. Glow discharge starters are the most widespread. A starter is a miniature lamp in which one or both electrodes are made of a bimetallic strip. Under normal conditions, the electrodes are at a small distance from each other.
When voltage is applied, a glow discharge arises between them, heating the bimetallic strips, which bend from the heat and close the circuit (1st stage of glow discharge). From this moment, a short-circuit current flows through the lamp electrodes, heating them to a high temperature (2nd stage). As soon as the contact closes, the discharge in the starter goes out; the bimetallic strips cool down and, returning to their normal state, open the circuit.
Starters have standard sizes. With this method, lamps do not light up instantly, starting units create noise, are heavy, bulky, and frequently fail. Recently, systems have been developed that allow fluorescent lamps to be switched on instantly, eliminate operating noise, and regulate them. A choke placed under the aquarium can also become an additional source of heat.
Fluorescent lamp wiring diagram with a starter (preheat start).
A traditional scheme used for a very long time, applicable when the mains voltage is sufficient to ignite the lamp. It uses a ballast representing a large inductive reactance—a choke, and a starter—a small neon lamp serving to preheat the lamp electrodes. A capacitor is placed parallel to the neon lamp in the starter to reduce radio interference. A capacitor can also be included in the circuit to improve the power factor.
When the lamp is turned on in the mains, a discharge first occurs in the starter, and a small current passes through the lamp electrodes, preheating them and thereby reducing the lamp’s ignition voltage. When a discharge occurs in the lamp, the voltage between the electrodes drops, disconnecting the starter circuit.
When using this fluorescent lamp scheme, the magnetic ballast (EMB) power must match the lamp power. The EMB in starter circuits is connected in series with the lamp and serves to limit current growth in the lamp (thus protecting it from burnout). We would like to draw users’ attention to the capacitor (0.22 µF) installed at the input. Often, aquarists simply throw it out of the circuit. The lamp will certainly work without the capacitor, but more voltage will be drawn from the power grid.
Using a similar starter circuit, two fluorescent lamps can be connected in series—this wiring scheme is called the “tandem” fluorescent lamp wiring scheme. When using this switching scheme, the power of the electromagnetic ballast must be twice the power of a single lamp.
Fluorescent lamp wiring diagram without a starter (rapid start).
The disadvantages of the circuit with a starter (long electrode warm-up time, need to replace the starter) led to the emergence of another scheme where electrode preheating is performed from the secondary winding of a transformer, which simultaneously serves as an inductive reactance.
A distinctive external feature of such a ballast is that both mains wires are connected to the ballast, and four wires from the ballast are connected to the lamp electrodes. There are many variations of this scheme, for example, when an electronic circuit disconnects the electrode preheating circuit after the lamp is turned on (trigger start). Ballasts of this type are also used in multi-lamp circuits.
You cannot use a lamp designed for a starter-type circuit in this setup because it is rated for longer electrode preheating and will fail prematurely in such a circuit. Only lamps marked RS (Rapid start) should be used. A grounded reflector along the lamp must be provided in the circuit (sometimes there is a metal strip on the lamp). This facilitates lamp ignition.
Fluorescent lamp wiring diagram without electrode preheating (instant start).
This scheme has come into use recently. In it, lamp ignition is produced by supplying a high-voltage pulse to the lamp electrodes. This scheme uses a special ballast that can be rated for multiple lamps. A distinctive external feature of such lamps and ballasts is the presence of only one electrode on each side of the lamp instead of two.
The advantage of this switching scheme is lower power consumption by the ballast (1-2 per lamp) compared to other magnetic ballasts, the possibility of independent parallel switching of lamps (usually in preheat and rapid start ballast schemes, the failure of one lamp causes the others to stop glowing), and the possibility of locating the ballast further away from the lamp (for preheat and rapid start, the wire length from the ballast to the lamp usually should not exceed one meter, although special ballasts exist).
Fluorescent lamp connection diagrams to ballasts.
Fluorescent lamp connection diagrams to ballasts.
Fluorescent lamp connection diagrams to ballasts.
Aquarium hoods with lighting equipment. Increasing lighting.
Ballast devices. Control gear for fluorescent lamps. 
