We bench test and rate the latest products from the major brands. Report by Lux technical editor Alan Tulla.
If you are considering replacing your existing fluorescent lamps with LED tubes, you have two choices.
If all you have to do is replace the lamp and starter (and nothing else), make sure that the LED tube complies with BS EN 62776:2015.
If you need to rewire the luminaire, such as bypassing the ballast, we recommend you don’t do it. I’ll explain why later.
There are thousands of T8 installations in the UK, some quite old and in need of refurbishment. There is also the increasing need to save energy. We tested LED tubes from 12 different suppliers. All the tubes were tested at the new Lighting Industry Association laboratories in Telford, UK. The results are shown below. We tested them for basic electrical safety, light output and flicker. According to the LIA, none of the LED tubes was totally correctly labelled as required by IEC 62776:2014.
Note that these LED tubes are unlikely to be suitable for use in luminaires which are used for emergency lighting. Neither can they be dimmed. The tube should carry some kind of symbol to this effect – see below.
Most of the tubes we tested had fixed end caps but some were rotatable. This means that the light emitted can be angled to direct it where you most want it. I.e. the LEDs do not simply point straight down.
Rotating them can be a bit fiddly since you have to adjust the end caps independently. It is much easier to do it at ground level than at height. On one of the tubes we looked at, the cap broke off the end of the tube even before we tested it! End cap strength is part of safety testing to BS EN 62776:2015 so that is another reason to check that your tube conforms.
The full title of BS EN 62776:2015 is “Double-capped LED lamps designed to retrofit linear fluorescent lamps. Safety specifications”. It runs to 34 pages of safety tests because there is a lot to consider. By placing a CE label on the tube the supplier is acknowledging that the product is safe and complies to the requirements of the Low Voltage Directive.
If your fluorescent lamp has an electronic ballast, you only need to swap the lamps. However, not all LED tubes are suitable for all HF ballasts. Some manufacturers, supply a ballast compatibility table.
If the fluorescent lamp has a magnetic or wire-wound ballast you will also need to replace the starter canister. No other rewiring should be required.
Note that this means that the wire-wound ballast remains in the circuit so it will still consume some energy. This may well affect the overall power factor depending on exactly how the original luminaire is wired.
There are also symbols indicating suitability for HF or magnetic gear. The symbol for this should be clearly marked on the tube.
You should ensure that full, complete and unambiguous installation instructions are supplied with the LED tubes. After conversion, the luminaire should have a label stating that it is no longer suitable for fluorescent lamps. Most LED tube manufacturers supply a label with the instructions.
If fitting the LED tube requires you to alter the wiring
(other than changing the starter canister), then our recommendation is that you don’t do it. Instead, choose an LED tube that can be simply retrofitted, as above.
The main reason we advise against rewiring is that you then become responsible for the luminaire complying with the relevant safety standards such as BS EN 60598.
Hopefully it will never happen but if there were an accident of any kind, the original luminaire manufacturer and your insurance company would be absolved of any responsibility. The LIA laboratory advise us that this is still the case if swapping the starter and retrofitting an LED tube. If something goes wrong with the magnetic ballast, even through no fault of the LED tube, the original luminaire manufacturer will deny any liability as they can claim the original product was not designed for LED tubes.
A final note about safety
When T8 LED tubes were first launched, there were serious concerns about the safety of some tubes where both pairs of pins became live once one pair was inserted in the luminaire. In this case, the free pins would be live and could easily be touched by the installer before inserting them into the second end cap.
Most importers and suppliers of these tubes are aware of this and now only sell 'Single-end connection' tubes. You must check that the tubes you are buying have a single end connection.
The LIA laboratory can also provide a limited safety assessment if in doubt of safety risks.
What else should I check?
Has the space changed its use?
The first point to make is that the activities in a space and ways of working often change over a period of time. When changing the lighting, you should re-evaluate what the lighting needs are. Obviously, the new scheme should meet the requirements of EN 12464-1 for health and safety reasons, if nothing else. There is plenty of design guidance available from the SLL, ILP and other sources – such as our Design Clinic!
Don’t forget the walls
There is a tendency when energy saving just to consider the horizontal illumination but for many areas such as offices, corridors and car parks, the vertical illumination (how well you can see someone’s face or read a notice board) is as important.
High power LEDs can be more glaring than a T8 lamp. If you think glare may be an issue, compare two luminaires side by side or run a glare calculation.
It’s very easy to achieve high efficiency in terms of lumens per watt if you aren’t concerned about colour rendering. Any CRI greater than 80 should be OK for most applications. It is worth pointing out that the Energy Related Products (ERP) regulations already state that indoor lamps and luminaires should have a minimum CRI of 80 so if it were less, the tube would not be CE compliant.
As a general rule, an increase of 10C above the rated value of an LED tube (typically 25C) halves the life. If your tube is in a sealed luminaire, it may reach 30C or 35C, possibly more in the roof space of a high factory.
More details about all these aspects are in the LIA Technical Statement TS 14.
The tube is likely to carry one, or more, of these symbols:
The tube should carry this symbol if it is not suitable for emergency lighting.
The tube should carry this symbol if it cannot be dimmed.
These symbols indicate whether the tube is suitable for a high frequency (HF) ballast or a magnetic ballast.
Companies selling LED tubes onto the UK market must comply with the WEEE regulations. These require producers to fund their share of the costs of recycling waste lamps. Buying from WEEE compliant suppliers is vital, to ensure that these important environmental obligations are met. Non-compliant producers risk enforcement and prosecution by the Environment Agency.
See the latest LED lighting at LuxLive 2017, Europe's largest annual lighting event this November. The show takes place on Wednesday 15 November and Thursday 16 November 2017 at the ExCeL London. Entry is FREE – see the full programme of events and register to attend by clicking here.