‘I’m dimming mixed loads on a single circuit; do I need to do anything different when it comes to the install?’
We regularly take calls from installers wanting to find out whether there is anything that they should be aware of when dimming mixed LED loads. In our latest Tech-call 101, we explain all.
First of all, if you're working on a lighting installation where you’ve got a mixed LED load, as long as the fittings and fixtures are all dimmable LEDs, you can control mixed loads using any of Zano Controls’ LED range. There are just a few steps you need to take to make sure your install works as it should.
The issue with dimming mixed LED loads on a single circuit is that each type of dimmable LED lamp or driver has different minimum and maximum levels that it can be dimmed too. Set the maximum too high for one type of LED fitting and you will see flicker or dropout, or set the minimum too low for another type, and the same again - flicker or potential dropout.
As a quick summary, when dimming mixed LED loads on a single circuit, the steps you need to take are as follows:
Step 1: Calculate the total load & account for inrush current
Step 2: Choose the right dimmer
Step 3: Use Zano Controls’ exclusive Smart Settings to program the minimum and maximum levels to ensure no flicker and dropout across all lights on the circuit
Results: A flicker-free LED install
For more detail on these steps, feel free to read on:
Step 1: Calculate the total load & account for Inrush current
To eradicate the risk of a flicker and dropout, the first thing you need to do is calculate the total load of your install, account for inrush current and pair your lights with a dimmer that can cope with the load of the circuit.
If, for example, you have 6 downlights at 5W each, and 4 wall lights that require 2 x 4W LED candle lamps each, once you add that all together that’s 62W – before inrush.
When it comes to LED loads, inrush current is the surge or momentary burst of current that is drawn by the LED power supply. It mainly occurs when the lights are first switched on but can also happen during the mains cycle as the reservoir capacitor requires a charge.
Needless to say, the bigger the spike or the longer the duration, the more it will affect your LED installation, increasing the load and potentially changing the dimmer you need to install. Good quality LED lamps and drivers keep Inrush current to a minimum, but to be on the safe side and prevent Inrush from wreaking havoc on your install the best thing to do is read our guide on total load calculations.
Step 2: Choose the correct dimmer
In a scenario like the above where you have a total load of around 111W, this sits perfectly within the capabilities of a 0-150W/VA dimmer like our ZGRIDLED150. Module and plated versions are also available.
However, when it comes to calculating the total load of a mix of something like LED tape, that lists wattage per meter - e.g. 10 meters of LED tape at 9W per metre, mixed with 6 LED downlights at 6W each - the total load of this (with inrush accounted for) brings you to just over 150W/VA.
When working with a larger load, especially with the likes of LED tape, we recommend using a remote dimming pack such as the ZBARLED300 to be on the safe side. LED tape can consume a huge inrush current at start-up and our ZBARLED range is powerful enough to cope with this inconsistency.
If you were working with a larger mixed load of under 250W in total, and quality lamps such as 30 4W LED downlights, you would find that you would be sorted with a dimmer like the ZGRIDLED+, a 5-250W/VA dimmer that can cope with a higher wattage.
For more on how to choose the correct dimmer, you can use our interactive product finder.
Now all that has been covered and you have figured out the right dimmer for the job, we bring you onto step 3.
Step 3: Use Zano Controls’ Smart Settings to program the minimum and maximum levels
As we cover in the introduction, the problem installers face when dimming mixed LED loads is that each type of dimmable LED lamp or driver has different minimum and maximum levels that they can be dimmed too. To find out how to program Zano’s Smart Settings, click here, or to read more about what they do, visit their personal profile.
Most LEDs have a wide dimming range, but the difference is that some LED drivers can be dimmed down to 10%, while others can be dimmed down to 1% of full light levels. These levels vary between make, model and type of LED light source chosen. When you have mixed LED loads on one circuit, you will need to program your dimmers minimum settings so that they do not dip below the capacity of the LED fittings/fixtures with the highest minimum level. When using Zano's Smart Settings you can set the minimum level pre-set, whereby you are able to program the rotary controller’s lowest level after installation and ensure that the dimmer is programmed to keep within a consistent range of lighting output every time.
As with Zano’s minimum level pre-set, most LED drivers (found within every LED light source is a driver that converts the mains coming into the power required to run the LEDs) often have a point at which increasing the amount of mains power going in no longer increases the light output. Dimming above this point is often a big cause of flicker on your installations and can cause a loss in light output. When dimming mixed loads, you need to be wary of the maximum point in the same way you would be the minimum level. Simply find the point at which the lights appear to jump up and program the dimmer's maximum level just before this jump point. Here’s some more info on how to figure out if you have set your maximum level too high.
You can also pre-program the start level pre-set. When dimming mixed loads, an occasional side effect can be that some of the lights on the circuit fail to turn on if set to low levels.
With the start level pre-set, it ensures that the lights come on quickly even if the lamps have been dimmed to low levels before switching off. When you set this pre-set during installation, the lamps will warm up quickly to this chosen ‘start level’, before dimming back to the level they were previously dimmed to.
Can you mix LED and Incandescent?
While it might be difficult, it is far from impossible. Zano’s ZBARLED remote dimming pack is engineered to be much more robust than the average digital dimmer and is capable of supporting much higher loads.
While the primary feature of the ZBARLED is to support a high number of LED lamps on a single circuit, it also makes it a perfect problem-solver when it comes to mixing LED and Incandescent lamps. Our ZGRIDLED is also capable of supporting mixed loads but at a limited level.
And that’s it folks - the comprehensive guide to dimming mixed loads on a single circuit.
Remember if you are not 100% certain on what dimmer you need for a mixed load project, want to submit lamps for testing or need support with project specification just give us a call on 0345 519 5858 or email sales@zanocontrols.co.uk.
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