Converting high-power E40 lamps to LED

Workshops, warehouses, sports halls and yards still run powerful E40 incandescent and halogen lamps. Switching them to LED means checking size, weight, heat and the fitting.

On the ceiling of an old workshop, above a sports hall or in a floodlight in a factory yard, large E40 screw lamps are still hanging. Among them are incandescent lamps rated in the hundreds of watts and powerful halogen lamps with the same cap. They light large areas, but they consume a lot of energy and give off heat. Moving to LED makes sense, but in the E40 world the switch is a little more involved than changing a household bulb.

What E40 is and where it remains

E40 is the largest widely used size of Edison screw cap, about 40 mm in diameter. It is normally used for high-power lamps: large incandescent lamps, halogen lamps, and the discharge lamps found in street and industrial fittings.

This article deals mainly with incandescent and halogen E40 lamps. Mercury, sodium and metal halide lamps run with a ballast and ignitor, and converting them to LED requires a separate check of the circuit. Incandescent and halogen lamps connect directly to the mains, so replacing them with an LED lamp is simpler from a wiring point of view.

Why switch to LED

The main drawbacks of powerful incandescent and halogen lamps are clear:

• most of the energy turns into heat, which adds to the warmth of a workshop or hall in summer;
• their service life is short, and on a high ceiling every replacement takes a lift and time;
• the bulb gets very hot, and the fire risk increases when it is covered in dust and grease;
• part of the light is wasted upwards and sideways.

An LED lamp gives the same light at far lower power, runs cooler and lasts longer. In buildings with high ceilings, saving on maintenance is often as important as saving energy.

Choosing: lumens, not watts

Choosing an LED lamp by the wattage of the old one is a mistake. First establish how much light the old lamp produced, its lumens. The lumen figure may not be on an incandescent lamp's packaging, in which case check the manufacturer's information or the data sheets of similar lamps. Halogen lamps give somewhat more light than incandescent lamps of the same wattage.

Then compare the LED lamp's lumens. But the number alone is not enough; light distribution matters too. An incandescent lamp spreads light in all directions, whereas many powerful LED lamps direct light mainly downwards or sideways. In a fitting with a reflector, this difference can change the result considerably: sometimes an LED lamp with the same lumens works better with the reflector, sometimes worse.

Think about light colour as well. Incandescent and halogen light is warm and yellowish. Neutral white is often more comfortable in workshops and warehouses, but in decorative or historic buildings you may want to keep a warm tone.

Size, weight and the fitting

E40 LED lamps have large bodies and heat sinks, so check the following:

• Size. The LED lamp can be longer and wider than the old one. It must fit inside reflector and enclosed fittings, and the protective glass must still close.
• Weight. High-output LED lamps are heavy. Make sure the lampholder and fitting can carry the weight, especially when the lamp hangs cap-up with the bulb pointing down.
• Heat. LEDs run cool, but the driver is sensitive to heat. In a fully enclosed, unventilated fitting an LED lamp's life is shortened. Check whether the manufacturer permits use in enclosed fittings.
• Protection. In damp, dusty or outdoor conditions the fitting's ingress protection must be preserved; never leave out the gasket or glass to make an LED lamp fit.
• Lampholder condition. In ceramic lampholders that have worked for years with hot lamps, contacts may be oxidised and springs weakened. Check the lampholder along with the new lamp.

Adapters and alternatives

Adapters converting E40 to E27 are available. They can be a temporary solution, but with a large, heavy LED lamp an adapter means extra mechanical load and an extra contact. For a permanent installation, a lamp with a direct E40 cap is more reliable.

In some cases it makes more sense to replace the fitting rather than the lamp. If the old fitting's reflector is damaged, its body is corroded or it has run very hot, an integrated LED fitting or LED floodlight gives a better result. The condition of the fitting and how hard the ceiling is to reach decide the matter.

Steps for the changeover

• List the types, wattages and number of existing lamps.
• Separate incandescent and halogen lamps from discharge lamps.
• For each fitting, check the size limits, whether it is enclosed, and the weight it can take.
• Trial one or two fittings first and assess light distribution and brightness on site.
• If the trial succeeds, change the whole area with the same model and the same colour temperature.

Zaferoğlu Elektrik's catalogue includes a 500 W incandescent lamp and a JTT halogen lamp with E40 caps, as well as high-output T-shaped LED lamps for large areas. When choosing a model for a specific fitting, the product's technical details can be confirmed with the company.