In my view, T5 adaptors are generally speaking ‘miss sold’. In the push to get a quick sale, the adaptor is often described as being ‘plug and play’. The suggestion being that anyone can install an adaptor and that it’s as simple as changing the fluorescent tube and installing a replacement starter.
As a result of this perception, I had a fairly heated discussion with a client that I have a huge amount of respect for. The client in question wanted an installation price for a large building. In total more than 5,000 of our T5 adaptors will be required.
We gave the client a guideline price per unit and advised that the price could only be confirmed after a site survey by the installation company that we were recommending. In this case the company that we were recommending for the job was EMS Ltd – who have just won ‘Electrical contractor of the year’ for the second year in succession.
The client wasn’t happy – he explained in no uncertain terms that he wouldn’t consider paying that much ‘for a tube change’.
Somewhat aggrieved, we pointed out that it wasn’t ‘tube change’, but a complete overhaul of the light fitting, removing the power factor correction capacitor, renewing wiring and replacing the lamp holders were necessary, as well as installing the T5 adaptor, new T5 tube and starter and cleaning the diffuser before refitting it.
His reply cut straight to the point – as usual! “You didn’t tell me the quote was to refurbish the fitting – that makes more sense – still too bloody expensive though!”
We still don’t know whether or not this particular job will go ahead. But that’s not really the point.
When installed professionally, the light fitting is effectively ‘refurbished’. The end result is a light fitting that should go on to provide years of maintenance free life.
There is no reason why a fitting that has been properly refurbished shouldn’t last 30 – 35,000 hours before a tube change is required. That’s between 6 and 7 years if the lights are used for 14 hours a day every day of the year.
We monitor the failure rate of our T5 adaptors. At the moment the national failure rate is less than 1%. We think that this is a pretty good percentage – but we are constantly looking for ways to reduce it even further.
So, having had the discussion with the client about the benefits of ‘refurbishment’, we had a look to see if we could find any hard evidence to support our view that this was the better and ultimately more cost effective option.
The starting point was our failure log. What we have found is that the failure rate is at its lowest when the T5 conversion was carried out by a good installation company or a competent electrician who has been briefed properly.
In many cases the failure rate is zero.
The evidence we have is encouraging – but we can’t suggest that it is conclusive. We now need to look at the failures to see if there is a correlation between the failure rate and how the T5 adaptors were fitted.
Whilst we look into this, if you are looking for an excellent electrical installation company in the greater London area, I can highly recommend EMS Ltd – Chris Allum is the managing Director, ably assisted by Crispian Lorford and the rest of the team.
Welcome to our blog
Power factor correction – the potential cost of ignoring what’s going on inside your light fittings
Thursday, January 27, 2011
In our business we see a lot of old light fittings – some of them are nearly as old as I am – well ok, not that old! In our experience the major cause of damage to the fittings is heat.
We see wiring that has become brittle and lamp holders that have become so stiff that it’s almost impossible to fit a new tube without a liberal application of WD40.
We recently upgraded a college from T12 to T5 fluorescent lighting. Over 25% of the T12 lamps that we removed separated from the metal end caps as they were being removed from the fitting. The heat produced by the T12 lamps had ‘welded’ the tube end cap into the lamp holder and the glue holding the end cap to the tube had broken down over time. We had to remove the end caps with pliers to get them out of the lamp holders.
It wasn’t a difficult job – just time consuming - and it showed the damage that can be caused by heat. It also meant that each fitting needed to be refurbished, as part of the T5 conversion.
T5 lamps produce a lot less heat than T8 or T12 lamps – at least they do if they have been installed correctly. So one of the major benefits of converting an existing light fitting from T8 or T12 to T5 is the reduction in heat produced and therefore a longer life for the light fitting.
The heat in a wire is caused by the current that is passing through it. The more current that passes through the wire, the hotter it will become. Too much heat and the quality of the wiring will decay and in some cases the insulation on the wire can be ‘melted’ ultimately causing a potential fire risk.
So, as far as we are concerned heat is as much the enemy as power consumption - we want both to be as low as possible. That’s why its important to know what is happening with regard to power factor correction.
We have seen ‘energy efficient’ products that seem to produce a reduction in the number of watts being used by the fitting, but at the same time, produce a significant increase in the current being drawn. This is being caused by the ‘power factor’ correction.
Most of us learned at school that: Watts = Volts X Amps. The trouble is, like most things, its not quite that simple. The real equation is: Watts = Volts x (Amps X Power factor correction).
The reason that power factor correction tends to be ignored is that its supposed to be as close to ‘1’ as possible. When it is ‘1’ or close to ‘unity’ as it is often described, then everything is fine and watts = Volts x Amps, again.
The problems start when the power factor correction is significantly below 1. If the power factor correction is for example 0.5 – the effect will be that double the current, will be drawn.
This can cause a number of problems. As you know, there is a direct relationship between the current passing through wiring and its temperature – doubling the current will cause a big increase in the temperature of the wire and inside the light fitting itself. The increase in temperature may not lead to a direct fire risk, but it will certainly reduce the working life of the fitting and of the elements inside it.
For a large installation it can also lead to ‘nuisance tripping’ – or the lighting fuses blowing on a regular basis. The solution to this problem is not to fit a bigger fuse – you need to find out what is causing the problem in the first place.
There is a good chance that if you have recently had a lighting conversion carried out and this is happening – that power factor correction is the cause.
We have tested our T5 adaptors in light fittings that don’t have a power factor correction capacitor in the fitting. Typically we measure a power factor of between 0.97 and 0.99 – pretty good!
However, the same T5 adaptor installed in a fitting that has a power factor correction capacitor already will often result in the combined pf value falling to as low as 0.4. Not so good – in fact a major problem.
The solution is simple. If you are using a T5 adaptor check to make sure that there isn’t a power factor correction capacitor in the fitting already. If there is, remove it. It only takes a moment – although obviously the work should be carried out by a properly qualified person.
We see wiring that has become brittle and lamp holders that have become so stiff that it’s almost impossible to fit a new tube without a liberal application of WD40.
We recently upgraded a college from T12 to T5 fluorescent lighting. Over 25% of the T12 lamps that we removed separated from the metal end caps as they were being removed from the fitting. The heat produced by the T12 lamps had ‘welded’ the tube end cap into the lamp holder and the glue holding the end cap to the tube had broken down over time. We had to remove the end caps with pliers to get them out of the lamp holders.
It wasn’t a difficult job – just time consuming - and it showed the damage that can be caused by heat. It also meant that each fitting needed to be refurbished, as part of the T5 conversion.
T5 lamps produce a lot less heat than T8 or T12 lamps – at least they do if they have been installed correctly. So one of the major benefits of converting an existing light fitting from T8 or T12 to T5 is the reduction in heat produced and therefore a longer life for the light fitting.
The heat in a wire is caused by the current that is passing through it. The more current that passes through the wire, the hotter it will become. Too much heat and the quality of the wiring will decay and in some cases the insulation on the wire can be ‘melted’ ultimately causing a potential fire risk.
So, as far as we are concerned heat is as much the enemy as power consumption - we want both to be as low as possible. That’s why its important to know what is happening with regard to power factor correction.
We have seen ‘energy efficient’ products that seem to produce a reduction in the number of watts being used by the fitting, but at the same time, produce a significant increase in the current being drawn. This is being caused by the ‘power factor’ correction.
Most of us learned at school that: Watts = Volts X Amps. The trouble is, like most things, its not quite that simple. The real equation is: Watts = Volts x (Amps X Power factor correction).
The reason that power factor correction tends to be ignored is that its supposed to be as close to ‘1’ as possible. When it is ‘1’ or close to ‘unity’ as it is often described, then everything is fine and watts = Volts x Amps, again.
The problems start when the power factor correction is significantly below 1. If the power factor correction is for example 0.5 – the effect will be that double the current, will be drawn.
This can cause a number of problems. As you know, there is a direct relationship between the current passing through wiring and its temperature – doubling the current will cause a big increase in the temperature of the wire and inside the light fitting itself. The increase in temperature may not lead to a direct fire risk, but it will certainly reduce the working life of the fitting and of the elements inside it.
For a large installation it can also lead to ‘nuisance tripping’ – or the lighting fuses blowing on a regular basis. The solution to this problem is not to fit a bigger fuse – you need to find out what is causing the problem in the first place.
There is a good chance that if you have recently had a lighting conversion carried out and this is happening – that power factor correction is the cause.
We have tested our T5 adaptors in light fittings that don’t have a power factor correction capacitor in the fitting. Typically we measure a power factor of between 0.97 and 0.99 – pretty good!
However, the same T5 adaptor installed in a fitting that has a power factor correction capacitor already will often result in the combined pf value falling to as low as 0.4. Not so good – in fact a major problem.
The solution is simple. If you are using a T5 adaptor check to make sure that there isn’t a power factor correction capacitor in the fitting already. If there is, remove it. It only takes a moment – although obviously the work should be carried out by a properly qualified person.
1
