LED inrush

[dawsirn]

I'm going to look at a job this week at a warehouse which requires replacing all the existing 6 foot twin fluorescent fittings with LED versions. They've requested the fittings are kept as they're relatively new so will look to bypass ballast etc. Not sure on the number but it'll be a few dozen I imagine....

Anyways I was wandering if the inrush currents of LED tubes are anything like that of the existing HF electronic ballasts or would they be much higher. I'll be contacting a couple of different manufacturers tomorrow on the issue but didn't know if anyone has had any experience with the LED tubes.

The same question applies to the modular LED panels 1200x600mm and the older fluorescent equivalent as the offices there want updating too.

If the Inrush currents are much higher then I'll be checking the switching arrangements and other circuit details to see if existing layout is suitable.

Obviously not expecting in depth analysis just seeing if anyone has had much experience updating fluorescent to LED and having Inrush current issues.

Once I've spoken to manufacturers I'll update this thread with any useful information found!
Cheers

 

[Marvo]

I guess it would depend on the exact equipment but all the LED fluorescent retrofits I've been involved with the inrush current of the LED's was lower than fluorescents so it wasn't a problem. Maybe if the fluorescents are electronic ballasts though you could possibly see a higher inrush with LED's.

 

[sparksburnout]

Why do you imagine LED tubes would have high inrush currents????

 

[amlu]

Why do you imagine LED tubes would have high inrush currents????

lots of capacitors to be charged up in the led tubes internal power supplies.

 

[sparksburnout]

lots of capacitors to be charged up in the led tubes internal power supplies.

Greater or even comparable to the existing florry's?? Don't think so.

 

[dawsirn]

There's no real electrical engineering reasoning to it at the moment , just aware high inrush currents for LED drivers but not sure how they compare with fluorescent.
Will know more once I speak to the manufacturers of preferred brands but just thought I'd see if anyone else has had dealings with these these particular type of fittings first.

Thanks

 

[Marvo]

It's something that's going to be difficult to measure or ascertain accurately in advance, I'd suggest just check the circuit impedance and see if you can make disconnect times on a c curve MCB. If you can then you should be covered, if you can't then maybe make an allowance in your quote for splitting the circuit into two if necessary.

 

[Adam W]

I changed a load of fluorescent battens in a long corridor to integrated LED battens; I think they're on pretty much 24/7 so no obvious issues with the LEDs causing inrush currents, but there's a store room adjacent to the corridor with 2 old fluorescent fittings in it, controlled by a vacuum switch. When the lights in the store room were turned on the LED battens in the corridor which were on the same circuit would flicker as the fluorescents started. I disconnected one of the fluorescent battens and the lights still flickered. Disconnected the other one and the flickering stopped.

The lights in the store room were to be changed for LED anyway, and there hasn't been a problem since, but this illustrates that LEDs can be sensitive to inrush currents. I've had a report from a cleaner that when she starts up the vacuum cleaner it makes the LED battens flicker, but I have yet to verify this personally.

 

[Marvo]

It may have been the fluorescents were interfering with built-in LED drivers causing the flicker. Apart from creating harmonics, switch mode type drivers are also susceptible to phase angle and harmonic issues on their supply.