8.2 Old EU Directive

The EU first of all classified fluorescent lamp ballasts by the overall power intake of the ballast and lamp circuit, targeting at gradually phasing out the less efficient models. For instance, the classes and limits for linear lamps are displayed in Table 8.1. The clue about class A1 is that these values refer to dimmable electronic ballasts. A ballast is classified A1 if it fulfils the following requirements:

• at 100% light output setting the ballast fulfils at least the demands of class A3;
• at 25% light output setting the total input power does not exceed 50% of the power at the 100% light output setting;
• the ballast must be able to reduce the light output to 10% or less of the maximum light output.

Now it would have looked somewhat odd to see the losses decreasing from class D all through class A2 but then to come across the inconsistency of an increase again towards the »upper class« A1. So an appropriate definition was invented that says the rated power is that measured at 25% light output, since a dimmable system will not always be run at full power. This is just as logical as saying a car’s engine does not always need to supply its maximum power, so if the car’s top speed is 200 km/h, let’s rate the engine power necessary to drive the car at 50 km/h as the nominal engine power.

Supplementary to this comes the curious fact that electronic ballasts are promoted with lower heat losses inside the ballast being one of the chief arguments, while named Directive allows higher losses in an electronic ballast than in a magnetic one. For instance, in Table 8.1 we learn that a 58 W lamp together with a magnetic ballast must not exceed a consumption of 64 W to comply with the requirements of class B1. This allows for a loss level of 6 W. However, when we shift to class A3, the lamp power drops to 50 W and the systems power to 59 W, allowing for a loss level of 9 W for the allegedly better ballast (Figure 8.2).

Fig 8.2: Split of system input power across a 58 W T8 lamp and its ballast

This does not matter so much, though, since this Directive fixes the entire gross power consumption of a system as a criterion. Basically this yields a correct approach, yet the good idea turns out as a disadvantage for magnetic ballasts, because, as mentioned in the introduction, electronic ballasts feed less than the 50 Hz rated power into the lamp.

Table 8.1: Values and classes of linear fluorescent T8 lamps with ballasts

It is argued that on account of the high operating frequency the lamp efficiency was better and therefore the luminous density nearly the same, only 4% less. First of all, the criteria neglect these 4%, since the Directive values and classes specify electric power only, not light output. Second, the EU realized later that the price premium for an electronic ballast was very high (table 3.1, section 3.3), while converting from a poor to a good type of magnetic ballast proved much more cost efficient (Table 8.2). Mind that these calculations were done without any consideration of interest rates for the invested capital!

Table 8.2: Payback periods for improved magnetic and electronic ballasts

Of course is has to be borne in mind that discounts of up to 80% from these prices may be achieved by industrial customers – not so much by electrical contractors. But then it should also be considered that mentioning the 4% difference in light output is not yet telling the full truth, since this difference does not refer to the rated power but to the deviating actual power intake of a lamp with a good magnetic ballast operated at rated voltage. A deliberate usage of the very generous tolerance margin, which in principle would not any longer be required for today’s precise production methods, makes this possible. Still, even with this ballast design the same lamp is about 4% brighter than the same lamp with an electronic ballast, as will be seen in the next section. The 5 W difference between a class B1 magnetic ballast and a class A3 electronic ballast for a 58 W lamp, which the values of Table 8.2 are based on, thereby dwindles away to leave hardly any more than 2 W. So the indicated payback periods remain valid even for the high rebates when real electrical values measured at equal light outputs are compared.

Therefore named EU directive so far aimed at phasing out merely the classes C and D, which was done in November 2005 and May 2002, respectively, and which indeed is not a pity. Then, the market and technologies available so far will be investigated and assessed once again and further steps decided according to the results. So this is by far not a displacement plan for magnetic ballasts, as had been the initial intention and is still often believed even within the lighting industry. After all there would have been little sense in doing so, since, as the directive itself mentions at a different point, the improvement steps so far defined can be achieved with a cost premium around 2 € per lamp, while all improvements necessitating a conversion to electronic ballasts comes at an additional cost of 20 € per lamp.