Overloading query / Issue dimmer turned off

  • September 19, 2017 at 09:56 #24092

    Hey Guys,

    I have two questions. Firstly, I have a LW400 dimmer powering 11 7-watt downlight LED bulbs. This situation worked fine for about a day but then all of a sudden the lights went off. The dimmer still had the blue LED lit. I then tried turning it off, so the amber LED showed, but none of the 11 7-watt downlight LED bulbs turned on / off. I tried reseting the switch and unlinking it but nothing happened. I turned the power off to my house and on again. The dimmer went of all together and is completely dead. Does this sound like an overloading issue? I have various other LW400’s around the house powering different sets of the same brand LED bulbs, though admittedly significantly less in terms of wattage, and they work fine.

    Secondly, what is the minimum LED loading for the LW400 dimmer and how can you calculate this? I have been told…

    – LW400 load is 60W LED or 250W Hallogen

    – LED loading can be calculated by just multipling the amount, so 11 7-watt would be 77

    – LED loading can be converted into Hallogen equivelant by multiplying by 5 so 11 x 7 x 5 = 385w (I read this somewhere but the equation looks and sounds wrong)

    – An electrician told me that dimmers don’t have seperate loading specifications for different types of bulbs. They said that if a dimmer has a maximum load of 250w you just make sure the LED load stays below 250. 250w dimmer % 7-watt LED bulbs = 35 LED bulbs. This also sounds wrong.


    September 20, 2017 at 18:32 #24096

    I have exactly the same issue with an LW400 aswell. Its been replaced once and now the replacement has the same issue.
    Is there a bad batch?

    I have 10 x 5w Megaman dimmable led lamps on this circuit, so not overloaded according to all the info I can find.

    Any help greatly appreciated ( The wife wants to go back to std rotary manual dimmers! 🙁 )

    September 21, 2017 at 13:15 #24099

    LightwaveRF only state the incandescent load, 20W min 250W max, and not LED load.

    As I understand it, the initial inrush current of the drivers in dimmable LED lamps means that it’s not just a case of adding up the wattage of each lamp as printed on the packaging.

    On https://www.simplyled.co.uk/easy-guide-to-dimming/ they give an example for a 400W max dimmer and say
    “…the rule of thumb for the amount of bulbs is to divide the 400W by 10, which then gives you 40 watts or rather, the maximum worth of LED bulbs for the dimmer…”
    “…8 bulbs (8 x 5W = 40W x 10 = 400W)…”

    My Mazda CX-3 Blog: jtonline.info
      Home automation: 1 x LW930 Lightwave Link / 4 x LW400WH Dimmer / 1 x LW205 Wire-Free Switch / 6 x LW381 Basic On/Off Socket / 1 x LW830 In-line Relay 3000W / 1 x Echo / 2 x Echo Dot / 1 x Harmony Companion.
      September 21, 2017 at 16:54 #24100

      I read that same article but it conflicts with guildelines Lightwaverf offer. They state that the maximum LED load for the LW400 is 60W with a maximum incandescent load of 250W. 10% of 250 is 25, so Lightwaverf’s recommendation for LED bulbs is slightly under 25% of the recommended incandescent load.

      I have come to the conclusion that the technology is too new and there are no standards in place yet for LED bulbs and LED dimmers. I am slightly regreting buying into this product as the only way to successfully use the product is with trial and error – which costs money.

      September 22, 2017 at 09:47 #24105


      A couple of weeks ago I was pointed in the direction of a compatibility chart partly filled out by Lightwaverf. There is a Megaman 5w LED GU10 listed and it looks like it isn’t compatible with the LW400. I have just bought the Aurora Elite EN-dgu005/40. It flickers for 1 and 2 bulbs but looks fine from 3 – 10 with no buzzing. I am wanting to use 11 of these and it looks like it might work in my situation as 5w x 11 bulb = 55 and Lightwave’s minimum LED land for the LW400 is 60w.

      Again, continuities form my previous post, I am going to have to keep buying bulbs in batches of 11 until I find the brand that works. It cost me £50 for the Aurora bulbs.

      October 25, 2017 at 12:38 #24343

      I suffered the same problem, see my posts in another thread https://staging.lightwaverfcommunity.org.uk/forums/topic/advice-for-new-installation/
      To summarize, I had a working installation of 8 Megaman 6W dim-to-warm leds but added a further six leds which resulted in dimmer failure after a few tens of minutes. I tried a second dimmer which failed the same way.
      I decided to investigate the non-functional hardware. I discovered that each dimmer power module uses two power mosfets which are protected by a wired-in thermal fuse. In both cases of my failed dimmers, this fuse has blown. The fuse is a SETfuse K4, rated at 2 amps and 130 deg C. I could not find a local source for these so I have ordered some Profuse TZ-P130/2 replacements, costing about £1 each. The repair does require some electronic soldering skills but nothing beyond those of a tv/computer repair man. I will let you know if replacing these fuses restores operation.
      Fingers crossed!

      May 19, 2018 at 07:36 #25300

      Hi Zoodie
      did your fix work? I have blown one of my dimmers and rather than replace the whole lot it would be great to just replace a fuse.

      October 17, 2018 at 18:22 #25427

      @stringman: In a word YES!

      The replacement soldered-in fuses fit just fine. You will need a quite fine bit on your soldering iron. It may be easier for you to clip the old fuse lead leaving about 5mm of the old lead and solder onto that. I set the soldering iron temperature to 300 degrees Centigrade — I think JSJSLW used lead-free solder but I didn’t. The fuses were bought from ebay vendor vuelectroniccomponents:
      3 x TZ-P130/2 Fuse thermal 2A 6×6,5×2,8mm 130°C len.55mm PROFFUSE £3.30

      I attach JPEG of the dis-assembled switches post repair so thet you can see the carnage. My replacement fuses are the ones with the black sleeving on the wires.

      Sorry about my very slow response time — I seemed to have been missed off the forum auto-emails somehow so I didn’t know about your message, also I didn’t get around to doing the repairs until last Christmas. Then I didn’t use the repaired switches straight away because I bought a bucketload of Mk1 switches during Maplin’s fire sale.

      Fingers uncrossed now.

      You must be logged in to view attached files.
      October 17, 2018 at 18:24 #25429

      Oh iPhone JPEG too big.

      October 17, 2018 at 18:53 #25430

      I shrunk the dis-assembled switches image. (Fingers should not have been uncressed so early).

      You must be logged in to view attached files.
      April 18, 2019 at 20:31 #25467

      Hi – did the fuse repair work? I’ve just ordered some of those fuses because I’m at the end of my tether.
      I had a gen 1 Lw250 3 gang which lasted 5 years running 8x7w Philips leds. It eventually gave up in the way you described. I then bought a new Lw400 which lasted a day on the same circuit. My wife doesn’t want anything less than the 7w leds as it’s the kitchen and the Philips bulbs dim beautifully.
      So I replaced the 3 gang lw400 with a 4 gang Lw400 so that I would have a spare gang.. guess what. 3 weeks after purchase the 4 gang has gone pop.
      So I’ve been googling what I can do. I’ve got too much Lightwave stuff to replace it all and then I found your post.
      Hopefully I will be able to resurrect my dead dimmers!

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