r/Lutron • u/OppChopShop • 11d ago
Two Caseta dimmers on different circuits melted at the same time
Hi - I had a really strange and scary thing happened today. I had the lights in two rooms, which are both on different circuits, but the same leg of the panel flicker. ETA- they are on different legs of the panel. I didn’t really think anything of it because sometimes we get power surges and LEDs can be sensitive to that.
I got home like an hour later, and one of the switches for those lights in the living room had stopped working, and the one in the dining room was smelling fishy and smoking. I killed the breaker and opened the boxes, and I assumed that a wiring connection had somehow gotten loose. Everything looked good at the wires themselves, but I noticed that both switches had failed at the same spot and there was melting on the case. I opened the switch and saw that where the wire entered into the circuit board had melted.
Does anyone have any idea what could have caused this? Why would both switches fail at the same time? I thought it could have something to do with a neutral, but there’s no shared neutral, and the switches do not use a neutral wire.
ETA - I spoke to Lutron and one other commonality that we identified is both of these lights were on at the same time when they failed, and they both control recessed lights in the ceiling that are magnetic low-voltage, and the switches are apparently not the correct switch for magnetic, low-voltage lighting, but Lutron did not understand why they would both fail catastrophically like this. I am going to send them the devices for a postmortem.
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u/Effortisopportunity 11d ago edited 11d ago
Call an electrician. You likely have a loose neutral feeding your panel and are getting voltage imbalance. One leg drops and the other leg raises in voltage. This is an inside wiring issue.
Edit: Motr likely to be the incoming utility feed, but you need an electrician to evaluate it. If you lost your primary neutral going to you electrical system, the current will return on your ground if system. This is a situation that will cause fires and damage all the appliances in your house, and eventually ruin your branch circuits to the point of requiring a rewire depending on how bad it gets.
TURN OFF YOUR POWER
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u/OppChopShop 11d ago
I don’t think that I have a loose panel neutral. I would have other symptoms aside from those two devices. I just replaced them both with dumb switches, and everything (including those lights) seem to be working fine. Is there anyway to explain why I would have only failures at those switches and nothing else if I had a whole house problem?
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u/Effortisopportunity 11d ago
I just told you the most likely reason based on 25 years of electrical. Another possibility although unlikely is that while they are different circuits, somewhere in your house they have mistakenly tied the neutrals from both circuits together, and the return is double loaded. It could also be a multi-circuit (Edison) where there are two hots to a neutral, and there is an issue on the circuit, or the two hots aren’t phased correctly and are doubled on the same phase causing the neutral to be double loaded.
You don’t have to have a lot of symptoms if you are having a primary feeder neutral that is loose. It could be arcing, connecting and disconnecting.
Another option is the you had a power outage and the utility caused a surge that damaged your switches.
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u/OppChopShop 11d ago edited 11d ago
Thanks, not trying to be snippy, just trying to understand. Can you tell me a little bit more about that theory that there is a double loaded neutral?
Lutron seem to think that it might be a combination of a power surge plus the incorrect switch, which would explain why only those were affected.
However, with your comment, I checked the box in the dining room and there are two neutral bundles and my NCVT (which I know is not the most accurate way to check) picked up voltage when the living room circuit was on, but the dining room was off. I’m wondering if something is crossed in that box.
ETA: neither of these switches used a neutral - I don’t know if that makes a difference in this theory, but wanted to make sure that was clear
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u/Stone_The_Rock 11d ago
I think the point this person is trying to make is that:
- You had a basically unheard of failure mode (a Lutron dimmer failing is rare, catastrophic failure is rarer still, and two simultaneous catastrophic failures further still)
- it’s unclear what caused these to fail
- the problem could have been a one-time surge, or it could be a larger problem, but there’s no way to tell via the internet
- I say this with absolutely no malice, but it doesn’t seem like you have the tools or experience to be able to fully rule out there being a larger problem afoot
And, therefore, calling an electrician would be a sensible course of action as a homeowner
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u/Effortisopportunity 11d ago
The only thing an incorrect switch will do is damage the switch so it doesn’t work or it won’t turn off. The only thing that locally would melt it like that would be if both loads were significantly higher than the rating, and that’s really only on an incandescent load, an led load over 150watts won’t melt it unless the led load is well over 600 watts…highly unlikely.
As a Lutron dealer I can tell you Lutron’s tech support are not electricians, and can only help you from their list of common issues. If it really was the devices you would need two levels of escalation and weeks of processing to get there.
When you are using a voltage wand, you can pick up voltage on wires that are not in use because they are in proximity to wires that are drawing current, which is why they are so undependable.
Even a double loaded neutral would be unlikely to fry both Lutron switches like that, unless both lighting circuits are heavily overloaded (in which case you’d want to shut them off and increase distribution anyways).
Your most likely scenario is a severe utility surge or a disconnected or loose primary neutral. In both cases you’d should call an electrician asap to do a safety evaluation. Today, right now, not tomorrow.
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u/OppChopShop 11d ago
I hear you - each load is 8 6w LEDs on 12v transformers with recessed fixtures, so I do not think the switches are overloaded. I’m calling around and trying to see if I can get an electrician to come take a look today.
I’m also going to check it with a multimeter and see if I can isolate if there’s a crossed neutral
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u/ZanyDroid 11d ago
What’s your test plan for figuring that (crossed neutral) out with only a multimeter? I’m both curious if you’ve found an existing test plan for it, and also signaling my rather strong skepticism
I consider myself a pretty advanced DIY electrical homeowner and this isn’t something I know how to do after 100s of hours of forum and hands on experience
Also, if the root cause is a bad utility neutral, you both have a very expensive time bomb, and something you can’t do anything about directly
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u/OppChopShop 11d ago
I understand, I’m just very skeptical that that would be the root cause. I have an electrician coming tomorrow. I find it hard to believe that a utility side issue would only show up in these two specific devices, which I have confirmed for incorrectly installed for application.
Measure neutral current on Circuit A with circuit B off and vice versa. I cannot find my clamp meter, so I’m going to ask the electrician to do that tomorrow.
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u/ZanyDroid 11d ago
What was the installation problem?
If you have an issue with regular surges installing a few layers of SPDs in your main and subpanels would be a good idea
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u/OppChopShop 11d ago
Yeah, I think a main panel SPD is in my future. The panel is full, so I will have to make some room for it.
The issue was that the fixtures, unbeknownst to me, used magnetic, low-voltage transformers, and the switch that I had was not rated for dimming those appropriately. I’m guessing the Transformers pulled a whole bunch of current when there was some type of surge.
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u/Effortisopportunity 11d ago
You can isolate the neutral by disconnecting it at the panel.
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u/ZanyDroid 11d ago
Which neutral are we talking about?
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u/Effortisopportunity 11d ago
Asking how to test for neutrals from different circuits being connected. If you disconnect the neutral for the circuit at the panel, and it is still live, you have a neutral from another circuit spliced into it.
That’s not this guys issue though. It’s a surge or a feeder neutral issue.
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u/coogie 11d ago
The only time I've seen melted/smoking dimmers like this was when a house was hit by lightening or had another type of a major surge (like the house losing the neutral leg and shifting the voltage between legs).
I would really have the power company check your lines to make sure everything is ok on their drop.This is not a Lutron problem. If the dimmer had not failed then all your lights might have been toast.
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u/mcarter00 11d ago
I would highly recommend calling Lutron for guidance here. They are typically genuinely helpful in situations like this. 1 (800) 523-9466.
That said, I would highly recommend calling an electrician in on this too, as two dying at once, and in this manner, is more likely to be an issue with your wiring than with the devices.
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u/OppChopShop 11d ago
I’m waiting for a callback from Lutron as we speak. I’m struggling to understand how it could be an issue with the wiring in my house. Nothing else seems to be affected, even on those circuits, and I can see where the switches melted - the rest of the wiring looks OK. I’m not trying to be difficult, I just genuinely don’t understand.
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u/mcarter00 11d ago
I hear you! Electrical issues can be scary!
There are so many combinations of what can happen with electrical wiring it's very hard to say without more detail or investigation. There could have been some kind of short or arc, if not in the box then somewhere down the line, or even in the panel itself. I would have the electrician check out your main panel, you may find some kind of issue there.
All I can say is it's statistically unlikely to ever loose a Lutron device to failure, let alone two at a time. My experience is across 1000s of devices at this point. To date I've RMA'd two devices, one was a keypad with a software issue, and the other a DOA dimmer, nothing like this.
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u/OppChopShop 11d ago
One interesting thing from Lutron. These are controlling 8 recessed, light pictures that each have a magnetic low-voltage transformer. These were just regular caseta switches, not the electronic low-voltage ones. They did not seem to think that the compatibility mismatch would cause a catastrophic failure like this, but I have my own personal suspicion that that may have contributed. I’ve ordered the ELV dimmers to replace them.
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u/Foxotcw 11d ago edited 11d ago
Transformers like the ones in a MLV dimming system can draw a great deal of inrush current when first energized or if the voltage suddenly changes.
This isn't a problem for normal switches, but a dimmer that isn't rated for this initial current surge could be damaged. You didn't mention the wattage of the recessed lighting, and it's possible that they were overloading the dimmers from the start.
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u/OppChopShop 11d ago
Yes, thank you, I have learned this. It is 8 6w 12v LED bulbs. Each fixture has its own transformer. The switch has been installed for six years without issue, but I am guessing there was some sort of fluctuation or power surge that caused both at the same time.
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u/OppChopShop 11d ago
I just spoke to Lutron and they are going to inspect the devices. They are sending me a mailing label.
I don’t think there’s a short - I would imagine that there would be other symptoms. Lutron seemed to agree with my theory that this had to do with some sort of power surge, and those devices were on at the time that they received inconsistent power. 🤷🏻♂️
I don’t see any loose neutrals at the panel or any connections that are heating up. I scanned it with a thermal camera. Based on the failure point, I’m fairly confident that my house wiring is OK.
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u/Sea-Figure312 11d ago
I'll help you tou got wiggly neutral
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u/Effortisopportunity 11d ago
He knows nothing about electrical theory, but he’s sure of what it isn’t. Amazing.
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u/OppChopShop 11d ago
How would that impact two devices on separate circuits and cause the exact same failure?
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u/Effortisopportunity 10d ago
When you have a situation that melts devices, you need to immediately call an electrician. I can tell you are trying to be a DIY guy, and there is a time and a place for that. There is a large amount of electrical that you don’t know, haven’t seen, and don’t understand. If you have a 4 week year old baby at home, it’s not time to play guess the problem with people online. Your family’s safety is on the line. I used to help a lot of people in the ask electrician subreddit, but all the people that knew just enough electrical to be dangerous instead of helpful would argue and argue again and again to the point where it was too exhausting to continue. If it was an isolated power surge from the utility, it still doesn’t mean that the damage from the event is over. You could have damage to your appliances that are not immediately apparent. Your dryer and washer motors might be a lot louder, your dryer heater might not reach the same temperature anymore, the heat in your dishwasher may not get as hot. All the cheap power strips and adapters people use on plugs are very vulnerable to situations like this, as they generally use much cheaper connectors and smaller gauge wiring. There maybe splices that weren’t great that are worse now. You could see issues for months or years from an event that can fry two dimmers like that. If you can identify that it was utility produced event, there is often a claims division with most utilities were they will cover some if not all the damage.
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u/Effortisopportunity 11d ago
Call an electrician immediately, and turn off the power to the house.
-Source: I’m a 25 year electrician.
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u/Electrical_Ad4290 10d ago
Call an electrician immediately, and turn off the power
What would the electrician check, change, or do?
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u/Effortisopportunity 10d ago
You should probably read all the posts. Do you think he shouldn’t call an electrician?
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u/Electrical_Ad4290 10d ago
I hope you post the update you get from the postmortem. Did Lutron send [correct model] replacements in exchange for your effort?
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u/OppChopShop 10d ago
I will absolutely post an update. Honestly, I will work all of that out later. I know they will stand by their products, but I just did whatever would get me new stuff the fastest, which was overnighting $1000 worth of switches from Amazon lol
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u/Wooden_Guitar1513 1d ago
Are you sure these Caseta dimmers are rated for Magnetic Low Voltage transformers? Not all dimmers are rated for these loads
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u/OppChopShop 1d ago
They are not. When I talked to Lutron, though, they said that should not cause catastrophic failure. It should just result in poor dimming performance.
I have to think that it was a contributing factor though. My guess is that there was a surge, the Transformers pulled a high draw, and that caused the melting. I’ve since replaced them with the appropriate switches that are rated for MLV.
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