Guide to Lamps

Select from our expanding range of lighting solutions


Choose the correct LED lighting and lamps for your workplace and you can drastically reduce your energy costs. Other key benefits of moving to LEDs include a reduction in maintenance costs due to extended lifetime of the lamps over conventional types.

This selection guide will help you to choose the right lighting for the job, whatever industry you are working in.

Topics in this guide

Selecting the shape


Selecting the base


Terms and attributes


LED retrofit key facts


Technologies we offer


Selecting the shape

Common shapes and styles available in our range:



A bulb shape designed to look more traditional which suits many older-style fittings


Specially designed for bright, targeted lighting. Ideal for panel installation in retail, showroom or display areas


Flame-shaped bulb, ideal for older-style fixtures


Two-pronged halogen bulbs typically used in industrial light fixtures

Ideal for applications requiring high luminosity



Ideal for chandeliers and similar fittings where added sparkle is desired

Filament Clear

300+ degree beam angle, ideal for glass luminaires for sparkle or for shades where a wide beam angle is needed


A soft warm diffused lamp where less glare is needed

Selecting the base

Please make sure to select the correct cap fitting when selecting your lamp. The diagrams below show some of the fitting types you will find in our range:






T5 & T8 Tubes




Select a base

Hover over a base type to learn more.


15mm Bayonet Fitting

Sometimes referred to as SBC, the smaller version of the standard push, twist and lock bayonet light fitting, still using the same locking mechanism as B22.


22mm Bayonet Fitting

The standard 22mm diameter bayonet light bulb mount that was, and is, most often used across the UK. This fitting ensures safety is maintained as it locks into position.


14mm Edison Screw

Sometimes known as SES, this is a smaller version of the standard Edison screw fitting E27. Often used for decorative lighting lamps.


27mm Edison Screw

Named after Thomas Edison, E27 is the standard screw-in base traditionally used across North America, now also used throughout Europe.


10mm GU Fitting

A twist and lock fitting typically used in domestic environments and suited to mains voltage of a higher wattage lamps - especially spotlights.

T5 & T8

Tube Fitting

Both using a bi-pin base, T5 is the smaller fluorescent tube size at 5/8" diameter. The larger T8 measures 8/8", or 1", The "T" refers to Tubular. Other sizes such as T12 are also available.


4mm MR11 Fitting

Standing for multifaceted reflector, MR11 fittings are used for halogen, and more recently, LED reflector lamps. The 11 refers to an overall diameter of 11/8" or 35mm.


5.4mm MR16 Fitting

Standing for multifaceted reflector, MR16 fittings are used for halogen, and more recently, LED reflector lamps. The 16 refers to an overall diameter of 16/8" or 51mm.


6.35mm GY6 Fitting

GY6 is a bi-pin fitting with a pin spacing of 6.35mm. Often used for low voltage capsule lamps in home or commercial display lighting.

Glossary of commonly used terms and attributes

Click to expand and read about the terms and attributes of LED lamps


Wattage: A measure of the energy consumed by a fitting.


Lumens: A unit of measurement used to translate how much illumination a light source provides.

CRI (Colour Rendering Index)

CRI (Colour Rendering Index): A numeric evaluation of the accuracy (in relation to "daylight" at 100) of various types of light source. CRI+90 lamps are ideal for lighting in galleries, museums, clothing stores etc, where accuracy of colour is critical.

Dimmable vs non dimmable

Dimmable vs non dimmable: Remember that not all lamps are dimmable. However dimmable lamps now exist that perform like traditional lamps, where the colour temperature gets warm as the lamp dims. Note: Some traditional dimmers do not work with LEDs, requiring the dimmer to be updated.

Beam angle

Beam angle: The point at which intensity of a source drops to 50% of maximum (centre reading) measured in degrees of the full angle.

Colour temperature

Colour temperature: A way to describe the light appearance provided by a light source. It is measured in degrees of kelvin (k) on a scale from 1,000 to 10,000.

Choose by colour temperature to influence a room's atmosphere. Lamps are available in a wide range of shapes and styles.

2700k : Warm white � ideal for bedrooms, living rooms restaurants, where ambience is needed.

4000k : Cool white � ideal for offices, kitchens, bathrooms, common in exterior fittings.

+6000k : Daylight � ideal for offices.


Lux: A unit of light measurement taking area into account, essentially it relates to the light intensity.

LED Retrofit - Key Facts

The innovation in lighting over recent years has given rise to many retrofit options for LEDs. Replacing lamps in existing fittings with LED equivalents is one of the easiest ways to make energy savings.

Decisions often must be made in terms of lumen values, colour temperatures, lamp styles and other factors but knowing a few facts about how and what to retrofit will set you in good stead.

Benefits of retrofit

Advances in technology constantly drive down LED replacement costs and bring many other benefits. These include:


Low energy consumption

Save up to 85% on energy costs with replacement LEDs. This fact alone can be enough to justify the change to LED, for both commercial and domestic users

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High efficiency

LED lamps produce far less heat than traditional incandescent types

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Instant light

Unlike CFL lamps, LEDs come on immediately when switched. There is no warm-up period

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Light colour

LED lamps can produce a light colour that is close to an incandescent lamp but whiter, colder colours are also available

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Lamp life

LEDs can now last 20 times that of incandescent lamps. This major benefit can lower ongoing maintenance and replacement costs tremendously

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Typical energy savings

Energy savings made by using LED against other types of lamp

Halogen (50W) Incandescent (60W) CFL (11-15W)
LED Equivalent 6.5W 11.5W 11.5W
SAVE 87% 81% 12-23%

Payback periods

When compared with halogen lamps, the payback period can be as little as 6 months

Watts / Lifetime Yearly Running Cost Cost over LED Lifetime
LED 6.5W / 25,000 hrs £1.00 £22.83
Halogen 50W / 2,000 hrs £7.67 £175.11
Savings per LED lamp £6.67 per year £152 lifetime
Saving for 8 LED lamps £53.36 per year £1,218 lifetime

Technologies we offer

Use one of these links to view the products on the RS website

LED Lamps

LED lamps use 80% less energy to create the same light output.


Fluorescent Tubes

Fluorescent tubes present a cost effective way to light large spaces.


Halogen Lamps

Halogen lamps use a halogen gas to increase light output and rated life.


HID Lamps

High Intensity Discharge lamps (HID) are known for their and long rated life.