stillwater Posted March 27, 2022 Posted March 27, 2022 I can't remember the sources but my memory is that I concluded back in 2014 or 2015 that the 2477D, rated 600 watts incandescent, was only good for 220 watts of LED load. I can't remember whether this was specific to my (SORAA VIVID GU-10) LEDs or generic. Also there used to be instructions for thermal de-rating of dimmers when in multi-gang boxes adjacent to other dimmers. Relay switches shouldn't be subject to thermal derating and the derating for LED for a relay versus a dimmer would depend a lot on the internal circuits in both the dimmer and the LED.
apostolakisl Posted March 28, 2022 Posted March 28, 2022 @Ajax One way to reduce inrush is to stagger the lights turning on. Not sure how you would do that simply. Also, putting a resistor in the circuit during startup, but again, not sure how you would implement that without getting fancy. Finally, if it were me, I would open up the 2447s and replace the relay . . . seeing as you may not be able to buy a new one ever again.
lilyoyo1 Posted March 28, 2022 Posted March 28, 2022 On 3/26/2022 at 4:20 PM, Ajax said: OK the results are in they peak at about 85W and settle down to 82W. Even at 85W you are looking at 765W why would the relay weld shut... I am sure that is what happened. Prob will switch out the 2477S in the bathroom for a dimmer and use that as a replacement Keep in mind, if your numbers are correct, you're still going beyond what the dimmer can handle. If your relay fused shut due to the current, most likely you'll be waisting a precious dimmer by swapping it in only for it to fail too while potentially having a fire hazard in waiting.
Ajax Posted March 28, 2022 Author Posted March 28, 2022 18 minutes ago, lilyoyo1 said: Keep in mind, if your numbers are correct, you're still going beyond what the dimmer can handle. If your relay fused shut due to the current, most likely you'll be waisting a precious dimmer by swapping it in only for it to fail too while potentially having a fire hazard in waiting. I have been using the 2477S for the LOAD wire the others 3x 2477D have no load attached to them. But yes for what they go for these days I dont want to waste anything!
apostolakisl Posted March 28, 2022 Posted March 28, 2022 7 hours ago, Ajax said: I have been using the 2477S for the LOAD wire the others 3x 2477D have no load attached to them. But yes for what they go for these days I dont want to waste anything! That is why I would open it up, remove the relay and try to find a suitable replacement, hopefully one rated for higher current. The only trick to opening them is that you have to drill out the rivet that holds the voltage rectifier to the heat sink. If you have a rivet gun and a little heat sink paste, it is no big deal to re-rivet when done. Another option would be to figure out if you could possible split the load over two switches. You say you have multiple switches controlling the load. Where any of these other switches ever part of a conventional 3 way or 4 way? If so, you might be able to use the traveler wires to shunt control of some of the lights to a different switch box.
stillwater Posted March 29, 2022 Posted March 29, 2022 (edited) Wow over 11 amps at 120 volts with inrush current probably several times that. I am a big fan of the Omron G9H hybrid relays though they cost $90+ sometimes you can find them new on Ebay for 1/2 or less. You'd have to match the "coil" voltage to what's in the dimmer and run coil wires outside the dimmer to the G9H because I doubt even one would fit inside the dimmer case. But they top out at 10 Amp continuous (80 Amp surge if I remember correctly). You could put two in parallel but that would be expensive and take extra some space. (It's not like putting regular electromechanical relays in parallel which doesn't work because one will make or break before the other. [Correction: Omron says only put SSRs in parallel as protection against open-state failure off one and not to increase current capacity because often only one would conduct due to differences in on-state voltage drop. ] Edited April 5, 2022 by stillwater Corrrection re relays in parallel
Ajax Posted April 1, 2022 Author Posted April 1, 2022 Would this work? https://www.smarthome.com/collections/insteon-switches/products/in-linelinc-relay-insteon-2475sdb-remote-control-in-line-on-off-switch-dual-band I can place this in the attic once i find the wire so the first 5 lights turn on then a program turn the other 4 on a couple seconds later?
stillwater Posted April 1, 2022 Posted April 1, 2022 (edited) Not sure what wiring configuration you have or intend. Are you thinking of an intentional delay to have two inrush pulses through the 2477s? If all there is in the ceiling is 2 wires + ground coming from the switch, then the 2475 would have to boot up before it could receive commands. This wouldn't be the best arrangement and it would also be more intelligence than you need. A DC relay fed from a wall wart through a series resistor and capacitor to ground could be set up to have a delay of maybe a fifth of a second (could easily be more) which would be enough to delay the inrush from the second group -- would be cheaper and more reliable than an insteon switch. If you have power and neutral in addition to the switched line in the ceiling then you could use the 2475 as you suggest but you could instead use a relay with a 120v coil just to switch the other 4 or 5 bulbs when the 2447s provides power. Also cheaper and more reliable than insteon. But without knowing the actual in-rush current for your bulbs and the ratings of the relays there is no guarantee that you'll get long life out of splitting the load in half. How long did the original 2477s last? There is also the alternative of putting an NTC (negative temperature coefficient) thermistor in series with each LED socket. For example a GE or Amphenol CL-140 NTC thermistor ($1.34 each in quantity 10 from Mouser) is rated 1.1 amp full load. It is 50 ohms at room temperature which would limit your start current to less than .4 amps per LED or 3.6 Amp total (would be less because there's some series resistance in the LED power circuit). At 75% of rated load -- the on (hot) resistance is 1.3 ohms so it would dissipate a watt for each bulb -- less than 2% loss. Actually you are closer to 100% of full load where the resistance is 0.9 ohms. There are also fancier soft-start circuits that might combine an NTC thermistor with a relay that would close after the inrush to eliminate the heat dissipation after the lights are on. Obviously test this on a bench with one lamp, wearing safety goggles, before installing. Edited April 1, 2022 by stillwater added note on testing
apostolakisl Posted April 1, 2022 Posted April 1, 2022 13 hours ago, Ajax said: Would this work? https://www.smarthome.com/collections/insteon-switches/products/in-linelinc-relay-insteon-2475sdb-remote-control-in-line-on-off-switch-dual-band I can place this in the attic once i find the wire so the first 5 lights turn on then a program turn the other 4 on a couple seconds later? The damage is from arcing which occurs when the relay contacts are close, but not quite touching and they arc. This occurs both when switching on and when switching off. Switching on is more of an issue here because of initial inrush. The delayed second switch of course would only be helping with turning on if you were to run them in series with each other. I would not do that, rather I would run them in parallel. If you put, say half of your lights on the in-line on/off switch you will reduce your current by half. This is the same idea as I mentioned earlier about using a second wall switch. Anyway, there would be no reason to have a delay, just put half of the lights on the in-line switch and then use Insteon to link the in line switch to the wall switch as a virtual 3-way. This would require figuring out how the wires are run and you would need a hot/neutral/load wire in each location for both the primary wall switch and the in-line switch. To summarize, you would be splitting the lights into two independent circuits. They would be acting together only because you use Insteon commands to link the switches to each other.
Ajax Posted April 1, 2022 Author Posted April 1, 2022 Thanks guys. I know when we wired the house I asked to still run the runner for the 3-ways (incase we ever wanted to remove insteon). I will pop the rest of the boxes and see what I find
Ajax Posted April 4, 2022 Author Posted April 4, 2022 OK I ended up taking the easy way out. I switched 3 of the out for the standard 15W LED bulbs. I also switched the switches around with one that I have not had any issues with. Both seems to be working for now. One thing I noticed that I wanted to get the collective's opinion. We built this house in 2020 so its pretty new-This is the second switch I found that the grounds (Bare copper) was not tied together in the box.... I know sometimes with the porcelain/plastic bulb holders they do that but is that OK? I might pull a couple more switches and outlets and see what I find.
apostolakisl Posted April 4, 2022 Posted April 4, 2022 1 hour ago, Ajax said: OK I ended up taking the easy way out. I switched 3 of the out for the standard 15W LED bulbs. I also switched the switches around with one that I have not had any issues with. Both seems to be working for now. One thing I noticed that I wanted to get the collective's opinion. We built this house in 2020 so its pretty new-This is the second switch I found that the grounds (Bare copper) was not tied together in the box.... I know sometimes with the porcelain/plastic bulb holders they do that but is that OK? I might pull a couple more switches and outlets and see what I find. The grounds are supposed to be tied together. If a cable comes from circuit panel to switch box A, then is spliced to the load wire going to fixture box B, and the ground wires aren't spliced then your fixture at box B will not be grounded regardless of what you do with the wire at that box. This means if the fixture fails and it develops a short to ground, the circuit breaker won't pop and the fixture itself will be live to touch. It is rare that fixtures short to ground, but it does happen and you will likely get shocked if you touch it and if you happen to be well grounded, you could even be killed. I would invite your builder back for a looksy and have all the boxes opened and corrected.
Recommended Posts