Toroidal transformer 230 V / 12 V
12 V AC · 50 to 1,000 VA · mounting dish supplied
4.9 · 51 reviews100 VA8.33 A at 12 V · Ø 97 × 37 mm
- Mounting disha single centre bolt
- Colour-coded leads230 V · 12 V
- Labelcolour code
- —
- —
- 2-year warranty · made in Gailhan
Key features
This 12V toroidal transformer, or toroid, steps 230 V mains down to 12 V AC for halogen lamps, 12 V pool lights and any equipment designed for 12 V AC. For the same rating, a toroidal transformer is lighter, more compact and quieter than a conventional transformer, and it mounts with a single centre bolt. It is supplied with its mounting dish; its leads are colour-coded: black for 230 V, red for 12 V. From 50 to 1,000 VA.
LED strips and many LED spotlights need 12 V DC: they require a 12 V LED power supply. Lamps marked “12 V AC” or “AC/DC” work on this transformer.
It is installed in an enclosure or cabinet, in a dry place, with air around it: it gets warm in normal operation.
The centre bolt must never touch both the metal base and the metal lid of an enclosure: it would form a shorted turn, which destroys the transformer.
When should you use a 12V toroidal transformer?
- 12 V halogen spotlights and lamps, indoors as well as for garden lighting.
- 12 V AC pool lights, with the transformer installed in the plant room.
- Replacing an original 230 V / 12 V toroid in an existing light fitting or installation.
- Equipment designed for 12 V AC, or rectified by its own electronics.
It supplies AC: for regulated 12 V DC (LED strips, electronics), choose a power supply.
Wiring the toroidal transformer
The colour code is repeated on the transformer label.
- Switch off the powerWork with the supply isolated and the circuit breaker open.
- Black leads to 230 VThe two black leads, the thinner ones, to line and neutral, behind a time-lag fuse or a type D circuit breaker.
- Red leads to 12 VThe two red leads, the thicker ones, to your lamps or pool lights, using cable of a suitable size.
- Mount itSit the toroid between its washers, cap it with the mounting dish and tighten the centre bolt without crushing the winding.
Testing the transformer. With the power off: continuity between the two black leads and between the two red leads, none between a black and a red. With the power on, by a qualified person: slightly more than 12 V off load on a multimeter set to V~.
Protection on the 230 V side
Time-lag fuse (T)
or type D circuit breaker, rated for the primary current: 0.43 A for the 100 VA. At switch-on, a toroid draws a high current.
Mounting
Centre bolt and mounting dish, without crushing the winding. The bolt must never touch both the metal base and the metal lid: it would form a shorted turn.
12 V side
At 12 V, the current is high: 8.3 A for the 100 VA. Over a long run, work out the cable size (see Pool).
Ratings and prices
From 50 to 1,000 VA. Above that, or for another voltage, custom-made.
| Rating | 12 V current | Primary current | Diameter × height | Weight | Price ex VAT |
|---|---|---|---|---|---|
| 50 VA | 4.17 A | 0.22 A | Ø 90 × 37 mm | 0.73 kg | €36.32 |
| 100 VA | 8.33 A | 0.43 A | Ø 97 × 37 mm | 1.25 kg | €43.99 |
| 200 VA | 16.7 A | 0.87 A | Ø 110 × 43 mm | 2.7 kg | €57.40 |
| 250 VA | 20.8 A | 1.09 A | Ø 133 × 48 mm | 2.75 kg | €66.99 |
| 300 VA | 25.0 A | 1.30 A | Ø 135 × 45 mm | 2.95 kg | €69.86 |
| 400 VA | 33.3 A | 1.74 A | Ø 145 × 57 mm | 4.1 kg | €84.80 |
| 500 VA | 41.7 A | 2.17 A | Ø 148 × 58 mm | 4.4 kg | €89.56 |
| 630 VA | 52.5 A | 2.74 A | Ø 152 × 60 mm | 4.9 kg | €93.39 |
| 750 VA | 62.5 A | 3.26 A | Ø 160 × 80 mm | 6.4 kg | €95.26 |
| 1000 VA | 83.3 A | 4.35 A | Ø 185 × 80 mm | 8.4 kg | €124.01 |
Catalogue dimensions and weights. Rated currents: rating ÷ 12 V on the secondary, ÷ 230 V on the primary.
12 V pool lighting
The toroidal transformer supplies the pool lights at 12 V AC. A pool installation must comply with IEC 60364-7-702 (NF C 15-100 in France): have it carried out or checked by an electrician.
Which rating?
Pool light power × 1.25: a 300 W halogen pool light needs 375 VA, so a 400 VA transformer. Two 30 W LED pool lights: a 100 VA.
Where should it go?
Outside zones 0, 1 and 2 of the pool, in a dry place, inside an enclosure: the plant room. Without an enclosure, choose the 230 V / 12 V pool transformer, in a sealed housing.
Which cable?
At 12 V, 300 W means 25 A: even over a few metres, the light dims if the cable is too small. Switching to LED cuts the current by a factor of ten. Work it out below.
| Cable size | Drop | Voltage at the pool light | Drop (%) | Verdict |
|---|
Target drop: 5 %. Copper cable, resistivity 0.0225 Ω·mm²/m (at operating temperature), outgoing and return conductors, reactance ignored. “Too small for this current”: current-carrying capacity of a PVC-insulated copper cable in conduit, two loaded conductors, for guidance only. Final sizing is the installer's responsibility.
Specifications of the 230 V / 12 V toroidal transformer
Values for the selected rating: 100 VA.
- Primary
- 230 V AC, black leads
- Secondary
- 12 V AC, red leads
- Rated secondary current
- —
- Rated primary current
- —
- Duty
- Continuous
- Type
- Toroidal transformer, two separate windings
- Diameter × height
- —
- Weight
- —
- Mounting
- Centre bolt and mounting dish (supplied)
- Connection
- Colour-coded flying leads, wiring label
- Ambient temperature
- 40 °C maximum
- Insulation class
- H
- Thermal protection
- On request
- Standard
- EN 61558-2-6, safety isolating transformers
- Compliance
- CE marking, RoHS
Frequently asked questions
About the 230 V / 12 V toroidal transformer.
How do you wire a toroidal transformer?
With the power off: the two black leads, the thinner ones, to the 230 V; the two red leads, the thicker ones, to your 12 V equipment. The colour code is repeated on the transformer label. On the 230 V side, fit a time-lag fuse or a type D circuit breaker.
What is the difference between a toroidal transformer and a conventional transformer?
For the same rating, a toroidal transformer is lighter and more compact, mounts with a single centre bolt, hums less and radiates less magnetic field around it. A conventional transformer, with E and I laminations, is fixed with four screws. Toroid or toroidal transformer: they are the same thing, a transformer whose core is a torus (a ring).
Toroidal transformer: 220V to 12V or 230V to 12V?
It is the same: 220 V is the former name for the 230 V mains. A 220V to 12V toroidal transformer connects to the same mains supply.
Is it suitable for 12 V LEDs?
For LED lamps marked “12 V AC” or “AC/DC”, yes. LED strips and spotlights marked “12 V DC” need regulated DC: choose a 12 V LED power supply.
Can it be used for pool lighting?
Yes, for 12 V AC pool lights. The transformer is installed outside zones 0, 1 and 2 of the pool, for example in the plant room, inside an enclosure. For a transformer already housed in a sealed enclosure, see the 230 V / 12 V pool transformer.
Can it be installed in a junction box?
It is not recommended: it gets warm in operation and must remain accessible. Install it in a sufficiently large, ventilated enclosure or cabinet, fixed with its mounting dish; a mounting plate lets you fit it on a DIN rail.
How do you test a toroidal transformer?
With the power off, an ohmmeter should show continuity between the two black leads and between the two red leads, and none between a black lead and a red lead. With the power on, by a qualified person, a multimeter set to AC (V~) reads slightly more than 12 V off load between the red leads.
Why is the off-load voltage above 12 V?
A transformer is designed to give 12 V on load: off load, its voltage is slightly higher. It returns to 12 V when the lamps are switched on.
What protection on the 230 V side?
A time-lag fuse (T) or a type D circuit breaker: at switch-on, a toroidal transformer draws a high current, which a fast-acting fuse or a type B breaker cannot withstand. The rating is chosen from the primary current, given in the ratings table.
Can I get 12 V DC?
With a bridge rectifier, you get unsmoothed DC, which suits motors or relays, but not electronics or LEDs. For LEDs, choose a 12 V LED power supply.
Is there a custom version?
Yes: other voltages, multiple secondaries, from 50 to 2,000 VA, on the custom toroidal transformer page.
Customer reviews
Reviews posted by customers who bought this transformer (in French).
Acheté pour un éclairage de piscine, totalement adapté et très facile a installer. Livraison rapide… parfait!
juste parfait, j'ai commandé le 29 décembre, livré le 03 janvier malgré les jours de fêtes. Le modèle 200vA que j'ai commander rempli parfaitement sa fonction, aucun bruit et aucune odeur contrairement aux produits chinois... Je ne peux que recommander !
Bon produit.Transfo en remplacement d' un en court circuit. Mise sous tension et contrôle de la tension secondaire conforme avant intégration
le transformateur correspond absolument a celui que je souhaite pour remplacer celui d une installation qui a grille . le delais de livraison tres rapide merci
Excellent produit. Réaction immédiate du service après-vente suite à la disparition du colis chez le transporteur: renvoi immédiat du produit commandé. Bravo pour la qualité de l'accueil et la rapidité d'action
Produit conforme, en stock et livré très rapidement
Other toroids and alternatives
Other voltages, custom builds, and solutions in a sealed housing or for DC. See all our 230 V to 12 V transformers.