Tech Call 101: how to dim GU10 LEDs

Tech Call 101: how to dim GU10 LEDs

GU10s are a great choice for spotlights and downlights – but it can be really frustrating to finish an install and see flickering or hear buzzing when pairing your GU10 lamps with a dimmer. To get the best possible dimming experience when using GU10 LEDs, we have a few golden rules to follow.  

Rule 1 - Use a digital LED dimmer 

Our first tip is to pay extra attention that you are using a digital LED dimmer, and not a leading-edge dimmer such as the Triac model. Leading-edge dimmers are traditionally used to dim incandescent and mains halogen light bulbs - and they aren’t made for LED. For a leading-edge dimmer to dim it needs to vary the point at which it turns on, this means that it often turns on at the peak of the mains voltage. When the dimmer does this, it sends the maximum current spike into the lamps that it is dimming.  

Triac dimmers, while made to solve the issues encountered when dimming LED are in fact a big no-no. They are made up of a large copper coil that is designed to absorb the current spike and lower the noise generated once the dimmer reaches its maximum loading capacity. However, when paired with LED, they too produce less than desirable results. Causing flicker, buzz, dropout, premature lamp failure, disturbance at low levels, and even reducing the lifespan of ur LEDs. All of which is not a good look for your GU10 install; is frustrating for the end-user; and will all too likely see you called back to the job by the customer.  

By removing the copper coil completely, digital LED dimmers avoid these interference issues. That is exactly we've done with our LED range of digital dimmers that are designed exclusively for LED. 

Rule 2 - Use the same GU10 lamp and model across your circuit, and make sure the lamps are dimmable 

If you mix and match your GU10s, it is likely that you will experience issues. There can be a lot of disparity between light output, colour temperature and dimming performance, even amongst lamps of the same manufacturer.  

By keeping the make and model the same it allows for consistent light output and will help prevent frustrating drop-out.  

We always advise buying high-quality dimmable LED lamps from reputable LED brands because they last longer and keep inrush to a minimum, which leads to this next point… 

Rule 3 - Account for inrush when calculating the total load of your install 

Calculating an LED’s potential Inrush current is so important when pairing your GU10 lamps with a dimmer. 

Inrush current is that surge of current that flows through the driver as the lamp powers up – in our testing labs, we have seen this regularly double the labelled wattage of some brands of LED lamps, with one 5W/VA downlight reaching double its labelled wattage. 

Simply taking the box wattage and not calculating potential Inrush current can leave you in a nasty predicament when it comes to the installation. Namely, because the disparity between box wattage and true wattage can mean you need a dimmer with a higher wattage capability than you might have already purchased – a 0-150W/VA dimmer could comfortably deal with the inrush from ten 5W/VA lamps, but not if their true wattage is closer to 20W/VA.  

Before choosing your dimmer, add up the box wattage and follow the industry standards of multiplying this load by 1.8 to get a better reading of the total load and what you are trying to control with a dimmer 

In summary, dimming GU10 LED requires that you:   

  • Always use a digital LED dimmer 
  • Don’t mix your lamp models 
  • Make sure you account for inrush

And there you have it – your full guide to dimming GU10 LEDs. If you are still stuck and need any more help, chat to our friendly team today and we’re more than happy to help. Give us a call on 045 519 5858, or you can email 



Back to blog