4 ms·

A smart electrical switch is going to destroy my home? Guess I've been living on borrowed time with my smart outlets.

by Spivak 3y ago

marcosdumay 3y ago
I'm always at loss if the fragility comments like the GP imply are really experienced by the commenter or if it comes from ignoring all the safety around things plugged on the mains power. Because yes, some homes are really vulnerable to electrical problems. And no, you can't trust any device (high-branded, non-name, DIY, whatever) on such homes. You can't even trust them to handle electricity being available, without any device consuming it.
1970-01-01 3y ago
If it overheats the PLA box and catches fire, very yes.
itishappy 3y ago
Most electrical fires are caused by faulty wiring and outlets, so yes, DIYing your own wiring and outlets can easily destroy you home... A 10A outdoor charger probably also deserves it's own breaker.
- bluGill 3y ago
  It isn't hard to DIY this right. You need to be careful and understand the NEC (or whatever your area uses), but the work isn't hard. I've seen professionals do some really bad work.
  - itishappy 3y ago
    Sure, but it's easy to fuck up too and the consequences are high. You're gambling with your home and most insurance won't cover DIY electrical work.
    - fr0sty 3y ago
      > most insurance won't cover DIY electrical work You have a good source for this? I see claims like this every time a discussion of this sort and they rarely come with any citations.
      - itishappy 3y ago
        No. It looks like you're totally right and the information I've shared is misleading, so let me do my best to correct that: Insurance will pay out, provided electrical fires are covered by your policy. They will then do their best to assign liability and pursue subrogation. If you did the work yourself, you're liable. If you're insured for that work, they'll come after your insurer. If you're not, they'll come after you. If your work is permitted and to code, you'll probably be fine, if not, good luck! So it looks like you're correct! Unlicensed work appears to be covered, but you may paid AND sued.
  - bastawhiz 3y ago
    Most things are easy to DIY, conceptually. It's also really easy to be competent but make a small mistake. It's extremely high risk, extremely low reward (as a function of cost and utility).
- brk 3y ago
  You can reduce this further by saying most electrical fires are caused by people touching things they are not qualified to touch (and by qualified I mean competent, not Certified, or anything official). If you are not comfortable with high voltage electrical work, or are not familiar with basic components of the electrical code that governs your area, then definitely don't do this. But mass-labeling the work of others as unsafe or harmful is not appropriate either.
- jeffbee 3y ago
  Moreover, several extremely large and destructive California wildfires were ignited by dodgy DIY wiring of outdoor loads like hot tubs. Seeing as how many cars are charged outdoors, a faulty EVSE is not something I want my neighbor to try to build.
- HeyLaughingBoy 3y ago
  You would probably have a heart attack if you saw all the watering trough heaters I have running from a single outside outlet all winter :-)
floatrock 3y ago
A smart electrical switch toggling your low-current LED lamp based on a motion sensor or other HA automation, probably not. A smart electrical switch toggling dozens of amps over several hours... this might be getting outside the realm of what I trust cheap chinese amazon products with fake, misleading, or no UL certifications to handle.
- Spivak 3y ago
  > dozens of amps So like two microwaves. It's also not running 20 amps through the Arduino, if the switch the software is flipping is rated for that much power then it's fine.
  - floatrock 3y ago
    "rated for" is iffy. In the DIY EVSE world, it's becoming well-known that the standard home depot-grade NEMA 14-50 outlet, although "rated" for 50amps, has a tendency to release the magic smoke. People suspect the traditional duty cycle used in rating these has been more for dryers, kilns, or welders, where they're active for an hour tops or at least not drawing full current. An EVSE can be at full power much longer, making the rating... less reflective of real-world conditions. I've heard there's a new rating system coming out designed especially for EVSE-sized duty cycles. And that's not even getting into things like torque specs for the connections, etc. None of this is blocking a dedicated, well-researched, and properly equipped DIYer, but at this level of power, there's enough "tricks of the trade" involved where the risk-to-reward ratio falls maybe outside the casual "buy things off AliExpress and who cares if the magic smoke comes out" range. At this current, spending an extra couple hundred bucks might be worth it to have an actual company with a non-made-up-syllables name and a non-Shanghai-alley address that my insurance company can go after if my garage goes up in flames because their UL claims were misleading.
bastawhiz 3y ago
You're not writing the software controller for your switch. You're not interfacing with the firmware of your giant lithium battery parked in your house. You're not soldering anything, or dealing with more than 15a or so. It's really not the same.
- HeyLaughingBoy 3y ago
  The software controller for that switch was probably written by the new guy fresh out of college with maybe a bit of oversight from his manager. You're not wasting your experienced Staff engineers on stuff like that.
- manchmalscott 3y ago
  An EVSE (what this project is) only does three things. It advertises the maximum amperage supported by the circuit, it listens for the car to say that it’s ready to charge, and then it supplies 120-240V AC line voltage across the main pins. No EVSE ever, including storebought, is “interacting with the firmware of your giant lithium battery”, the actual charger that turns the AC into DC and shoves it in the battery is built in to the car. You’re probably thinking about DC fast charging, where the charger is external to the car and connects directly to the battery. Nobody should be trying to make _that_ themselves with an Arduono, sure.
  - bastawhiz 3y ago
    If the EVSE is talking to your car but not the firmware of the car, then please explain what the hell it's talking to. Is it in the cloud? Is there a little man that lives in my car that replies? Getting the amperage wrong or sending power when the car is not ready both sound like astoundingly dangerous failure modes for a DIY project, even if the most damage is bricking your car's battery controller.
    - manchmalscott 3y ago
      if I plug in my phone and my phone isn't ready to start charging (say it detects an overheat, common in Arizona), it just… doesn’t start charging. Just because the cars onboard charger now has power available to it doesn’t mean it has to start charging the battery. The EVSE is talking to the onboard charger, the on board charger is what actually interacts with the batteries. The EVSE has a specific resistance inline with a comm pin to indicate presence (even when unplugged from the wall) and modulates a frequency on the comm pin to indicate max amperage. The car puts a specific resistance on a different comm pin to request that the contactors close to connect the charger to wall power. Any problems or bugs thereafter are with the onboard charger, not the EVSE.

A smart electrical switch is going to destroy my home? Guess I've been living on borrowed time with my smart outlets.

by Spivak 3y ago

A smart electrical switch is going to destroy my home? Guess I've been living on borrowed time with my smart outlets.

I'm always at loss if the fragility comments like the GP imply are really experienced by the commenter or if it comes from ignoring all the safety around things plugged on the mains power. Because yes, some homes are really vulnerable to electrical problems. And no, you can't trust any device (high-branded, non-name, DIY, whatever) on such homes. You can't even trust them to handle electricity being available, without any device consuming it.

1970-01-01 3y ago

If it overheats the PLA box and catches fire, very yes.

itishappy 3y ago

Most electrical fires are caused by faulty wiring and outlets, so yes, DIYing your own wiring and outlets can easily destroy you home... A 10A outdoor charger probably also deserves it's own breaker.

bluGill 3y ago
It isn't hard to DIY this right. You need to be careful and understand the NEC (or whatever your area uses), but the work isn't hard. I've seen professionals do some really bad work.
- itishappy 3y ago
  Sure, but it's easy to fuck up too and the consequences are high. You're gambling with your home and most insurance won't cover DIY electrical work.
  - fr0sty 3y ago
    > most insurance won't cover DIY electrical work You have a good source for this? I see claims like this every time a discussion of this sort and they rarely come with any citations.
    - itishappy 3y ago
      No. It looks like you're totally right and the information I've shared is misleading, so let me do my best to correct that: Insurance will pay out, provided electrical fires are covered by your policy. They will then do their best to assign liability and pursue subrogation. If you did the work yourself, you're liable. If you're insured for that work, they'll come after your insurer. If you're not, they'll come after you. If your work is permitted and to code, you'll probably be fine, if not, good luck! So it looks like you're correct! Unlicensed work appears to be covered, but you may paid AND sued.
- bastawhiz 3y ago
  Most things are easy to DIY, conceptually. It's also really easy to be competent but make a small mistake. It's extremely high risk, extremely low reward (as a function of cost and utility).
brk 3y ago
You can reduce this further by saying most electrical fires are caused by people touching things they are not qualified to touch (and by qualified I mean competent, not Certified, or anything official). If you are not comfortable with high voltage electrical work, or are not familiar with basic components of the electrical code that governs your area, then definitely don't do this. But mass-labeling the work of others as unsafe or harmful is not appropriate either.
jeffbee 3y ago
Moreover, several extremely large and destructive California wildfires were ignited by dodgy DIY wiring of outdoor loads like hot tubs. Seeing as how many cars are charged outdoors, a faulty EVSE is not something I want my neighbor to try to build.
HeyLaughingBoy 3y ago
You would probably have a heart attack if you saw all the watering trough heaters I have running from a single outside outlet all winter :-)

floatrock 3y ago

A smart electrical switch toggling your low-current LED lamp based on a motion sensor or other HA automation, probably not. A smart electrical switch toggling dozens of amps over several hours... this might be getting outside the realm of what I trust cheap chinese amazon products with fake, misleading, or no UL certifications to handle.

Spivak 3y ago
> dozens of amps So like two microwaves. It's also not running 20 amps through the Arduino, if the switch the software is flipping is rated for that much power then it's fine.
- floatrock 3y ago
  "rated for" is iffy. In the DIY EVSE world, it's becoming well-known that the standard home depot-grade NEMA 14-50 outlet, although "rated" for 50amps, has a tendency to release the magic smoke. People suspect the traditional duty cycle used in rating these has been more for dryers, kilns, or welders, where they're active for an hour tops or at least not drawing full current. An EVSE can be at full power much longer, making the rating... less reflective of real-world conditions. I've heard there's a new rating system coming out designed especially for EVSE-sized duty cycles. And that's not even getting into things like torque specs for the connections, etc. None of this is blocking a dedicated, well-researched, and properly equipped DIYer, but at this level of power, there's enough "tricks of the trade" involved where the risk-to-reward ratio falls maybe outside the casual "buy things off AliExpress and who cares if the magic smoke comes out" range. At this current, spending an extra couple hundred bucks might be worth it to have an actual company with a non-made-up-syllables name and a non-Shanghai-alley address that my insurance company can go after if my garage goes up in flames because their UL claims were misleading.

bastawhiz 3y ago

You're not writing the software controller for your switch. You're not interfacing with the firmware of your giant lithium battery parked in your house. You're not soldering anything, or dealing with more than 15a or so. It's really not the same.

HeyLaughingBoy 3y ago
The software controller for that switch was probably written by the new guy fresh out of college with maybe a bit of oversight from his manager. You're not wasting your experienced Staff engineers on stuff like that.
manchmalscott 3y ago
An EVSE (what this project is) only does three things. It advertises the maximum amperage supported by the circuit, it listens for the car to say that it’s ready to charge, and then it supplies 120-240V AC line voltage across the main pins. No EVSE ever, including storebought, is “interacting with the firmware of your giant lithium battery”, the actual charger that turns the AC into DC and shoves it in the battery is built in to the car. You’re probably thinking about DC fast charging, where the charger is external to the car and connects directly to the battery. Nobody should be trying to make _that_ themselves with an Arduono, sure.
- bastawhiz 3y ago
  If the EVSE is talking to your car but not the firmware of the car, then please explain what the hell it's talking to. Is it in the cloud? Is there a little man that lives in my car that replies? Getting the amperage wrong or sending power when the car is not ready both sound like astoundingly dangerous failure modes for a DIY project, even if the most damage is bricking your car's battery controller.
  - manchmalscott 3y ago
    if I plug in my phone and my phone isn't ready to start charging (say it detects an overheat, common in Arizona), it just… doesn’t start charging. Just because the cars onboard charger now has power available to it doesn’t mean it has to start charging the battery. The EVSE is talking to the onboard charger, the on board charger is what actually interacts with the batteries. The EVSE has a specific resistance inline with a comm pin to indicate presence (even when unplugged from the wall) and modulates a frequency on the comm pin to indicate max amperage. The car puts a specific resistance on a different comm pin to request that the contactors close to connect the charger to wall power. Any problems or bugs thereafter are with the onboard charger, not the EVSE.