Guía de accesorios de iluminación, Tapas y Bases

What Are the Different Types of Light Bulb Fittings, Tapas y Bases?

Al reemplazar una bombilla, choosing the correct montaje de bombilla, cap, o base is just as important as selecting the right brightness or colour temperature.

El cap (also called the base) is the part of the bulb that connects to the light fitting. It provides the electrical connection while securely holding the bulb in place. Since different fixtures are designed for specific bulb types, manufacturers have developed a wide variety of light bulb bases to ensure only compatible lamps can be installed safely.

Whether you’re replacing a household bulb, a spotlight, or an LED tube, this guide explains the most common light bulb fittings, caps, y bases to help you find the right replacement.

Gorro de bayoneta

Bayonet caps are easy to recognize thanks to their push-and-twist locking mechanism. They remain popular in the UK, Australia, Nueva Zelanda, and several other countries because they are secure, confiable, and simple to install.

BC B22 (Gorro de bayoneta)

Diámetro: 22milímetros

Pin-to-Pin Diameter: 27milímetros

Height: 26milímetros

El BC B22, also known simply as B22, is the standard bayonet cap used in many household light fixtures. It features two locating pins that lock into the socket with a short twist.

Las aplicaciones comunes incluyen:

• Luces de techo
• Lámparas de mesa
• Lámparas de pie
• Luces de pared
• Accesorios decorativos

Because of its durability and ease of installation, B22 remains one of the most widely used light bulb fittings.

SBC B15 (Casquillo de bayoneta pequeño)

Diámetro: 15milímetros

Pin-to-Pin Diameter: 17milímetros

Height: 26milímetros

Similarmente, el SBC B15 (Casquillo de bayoneta pequeño) works in the same way as a B22 but is smaller in diameter.

It is commonly found in:

• Iluminación decorativa
• Apliques de pared
• Iluminación de electrodomésticos
• Small table lamps

Although most B15 bulbs operate on mains voltage, some specialist versions are designed for low-voltage applications.

Other Bayonet Variants

In addition to B22 and B15, several specialist bayonet fittings are available, incluido:

• B22d-3 – Often used in Fireglow and industrial mercury lamps
• BY22d – Commonly used for low-pressure sodium (SOX) iluminación

Edison Screw Cap

Unlike bayonet fittings, Tornillo Edison (ES) caps screw directly into the socket. Named after Thomas Edison, they are now the most widely used light bulb bases worldwide.

ES E27

Diámetro: 27milímetros

Height: 26milímetros

El E27 Edison Screw is the standard screw fitting throughout Europe, Asia, Australia, and many other regions.

Sin embargo, it is often confused with E26. Although the difference is only 1mm, the two bases are designed for different electrical systems.

• E27: 220–240V
• E26: 110–120V (América del norte)

Always check both the fitting size and operating voltage before purchasing a replacement bulb.

SES E14 (Small Edison Screw)

Diámetro: 14milímetros

Height: 26milímetros

For smaller fixtures, el E14 Small Edison Screw is the preferred choice.

You’ll typically find E14 bulbs in:

• Candelabros
• Luces de pared
• Decorative pendant lights
• Iluminación de electrodomésticos
• Iluminación de acento

Gracias a su tamaño compacto, E14 is especially popular for decorative LED filament bulbs.

Common Edison Screw Sizes

Capsule Lamps

Compared with standard bulbs, capsule lamps are much smaller and use two metal pins instead of a screw or bayonet fitting.

The model number simply refers to the distance between the two pins, making it easy to identify the correct bulb.

This design also prevents bulbs with different voltages from being installed in the wrong fixture.

G9 Base

Espaciado de pines: 9milímetros

El G9 fitting is designed specifically for 220–240V mains voltage.

You’ll commonly see G9 bulbs used in:

• Luces de pared
• Decorative pendant lights
• Candelabros
• Iluminación debajo del gabinete

Hoy, LED G9 bulbs are widely available and provide an energy-efficient replacement for traditional halogen capsules.

G4 Base

Espaciado de pines: 4milímetros

By comparison, el G4 fitting operates on 12V and requires a compatible transformer or LED driver.

G4 bulbs are frequently used in:

• Iluminación del gabinete
• Iluminación de la pantalla
• iluminación del paisaje
• RV and marine lighting

GY6.35 Base

Espaciado de pines: 6.35milímetros

El GY6.35 capsule is another low-voltage fitting designed for 12V or 24V sistemas.

It is commonly installed in:

• Iluminación de tareas
• Lámparas de escritorio
• Display cabinets
• Iluminación de acento

Afortunadamente, LED versions are available for all these capsule bases, making upgrades simple while significantly reducing energy consumption.

Linear Halogen

R7s Fitting

Cap Diameter: 7milímetros

Bulb Length: 78mm or 117mm

Unlike capsule lamps, R7s linear bulbs have contacts at both ends.

They are widely used in:

• Floodlights
• Security lights
• Work lights
• Uplighters

When replacing an R7s bulb, always match:

• Longitud
• Potencia
• Voltaje

This ensures proper performance and safe operation.

Halogen and LED Spotlights

Spotlight bulbs are identified by the distance between their pins and the locking mechanism. Como consecuencia, different spotlight bases are not interchangeable.

GU10

Tipo: Twist & Lock

Espaciado de pines: 10milímetros

Operating directly from 220–240V mains power, el GU10 is the most common spotlight fitting used in residential and commercial lighting.

Hoy en día, LED GU10 bulbs are available in various:

• Wattages
• Beam angles
• Colour temperatures
• Brightness levels

making them ideal replacements for halogen spotlights.

GU5.3 / MR16

Tipo: Push Fit

Espaciado de pines: 5.3milímetros

Unlike GU10 bulbs, MR16 (GU5.3) spotlights require 12V power supplied by a transformer or LED driver.

They are commonly installed in:

• Iluminación de cocina
• Iluminación de la pantalla
• Retail lighting
• Iluminación de acento

GZ10

A primera vista, el GZ10 looks almost identical to a GU10.

Sin embargo, there is one important difference.

The GZ10 uses a dichroic reflector, which directs heat backwards rather than forwards. Como resultado, the base has a square profile that prevents it from being installed in fixtures not designed to handle the additional heat.

Compatibilidad

• ✅ GU10 → fits GU10 and many GZ10 fittings
• ❌ GZ10 → should not be installed in GU10-only fixtures

Fluorescent Tubes and LED Tubes

Both fluorescent and LED tubes use two-pin caps at each end. Sin embargo, different tube diameters require different base types.

G13 / P8

Tube Diameter: 25milímetros

Espaciado de pines: 13milímetros

El G13 fitting is the industry standard for T8 LED y tubos fluorescentes.

After inserting the tube, simply rotate it to lock it into place.

The same fitting is also used on:

• T10 tubes
• T12 tubes

G5 / T5

Tube Diameter: 16milímetros

Espaciado de pines: 5milímetros

Mientras tanto, G5 fittings are designed for slimmer T5 tubes.

These compact tubes are widely used in:

• Oficinas
• Exhibidores minoristas
• Iluminación debajo del gabinete
• iluminación comercial

The same cap is also found on some T4 fluorescent tubes.

Pensamientos finales

En conclusión, identifying the correct montaje de bombilla, cap, o base is essential before purchasing a replacement bulb.

Whether your fixture uses a B22 bayonet, E27 Edison Screw, E14, G9, GU10, MR16, R7s, o G13 fitting, selecting the correct base ensures a safe installation and optimal performance.

Finalmente, if you’re replacing an older incandescent, halogen, or fluorescent lamp, consider upgrading to an LED equivalent with the same fitting. Not only will you enjoy lower energy consumption, but you’ll also benefit from a longer lifespan, reduced maintenance, and improved lighting efficiency.