4 ms·

At least with U.S. wiring we have 15 amps at 120 volts. For continuous power draw I know you'd want an 80% margin of safety, so let's say you have 1440 Watts of

by jchw 1y ago

At least with U.S. wiring we have 15 amps at 120 volts. For continuous power draw I know you'd want an 80% margin of safety, so let's say you have 1440 Watts of AC power you can safely draw continuously. Power supplies built on MOSFETs seem to peak at around 90% efficiency, but you could consider something like the Corsair AX1600i using gallium nitride transistors, which supposedly can handle up to 1600 watts at 94% efficiency. Apparently we still have room, as long as you don't run anything else on the same circuit. :)

cosmic_cheese 1y ago
Where things get hairy are old houses with wiring that’s somewhere between shaky and a housefire waiting to happen, which are numerous.
- kube-system 1y ago
  Yeah, but it ain't nothing that microwaves, space heaters, and hair dryers haven't already given a run for their money.
  - jchw 1y ago
    Hair dryers and microwaves only run for a few minutes, so even if you do have too much resistance this probably won't immediately reveal a problem. A space heater might, but most space heaters I've come across actually seem to draw not much over 1,000 watts. And even then, even if you do run something 24/7 at max wattage, it's definitely not guaranteed to start a fire even if the wiring is bad. Like, as long as it's not egregiously bad, I'd expect that there's enough margin to cover up less severe issues in most cases. I'm guessing the most danger would come when it's particularly hot outside (especially since then you'll probably have a lot of heat exchangers running.)
- jchw 1y ago
  As an old house owner, I can attest to that for sure. In fairness though, I suspect most of the atrocities occur in wall and work boxes, as long as your house is new enough to at least have NM sheathed wiring instead of ancient weird stuff like knob and tube. That's still bad but it's a solvable problem. I've definitely seen my share of scary things. I have a lighting circuit that is incomprehensibly wired and seems to kill LED bulbs randomly during a power outage; I have zero clue what is going on with that one. Also, often times opening up wall boxes I will see backstabs that were not properly inserted or wire nuts that are just covering hand-twisted wires and not actually threaded at all (and not even the right size in some cases...) Needless to say, I should really get an electrician in here, but at least with a thermal camera you can look for signs of serious problems.
atonse 1y ago
You can always have an electrician install a larger breaker for a particular circuit. I did that with my "server" area in my study, which was overkill cuz I barely pull 100w on it. But it cost nearly zero extra since he was doing a bunch of other things around the house anyway.
- davrosthedalek 1y ago
  Larger breaker and thicker wires!
  - atonse 1y ago
    I thought you only needed thicker wires for higher amps? Should go without saying, but I am not a certified electrician :-) I only have a PhD from YouTube (Electroboom)
    - jchw 1y ago
      The voltage is always going to be the same because the voltage is determined by the transformers leading to your service panel. The breakers break when you hit a certain amperage for a certain amount of time, so by installing a bigger breaker, you allow more amperage. If you actually had an electrician do it, I doubt they would've installed a breaker if they thought the wiring wasn't sufficient. Truth is that you can indeed get away with a 20A circuit on 14 AWG wire if the run is short enough, though 12 AWG is recommended. The reason for this is voltage drop; the thinner gauge wire has more resistance, which causes more heat and voltage drop across the wire over the length of it, which can cause a fire if it gets sufficiently hot. I'm not sure how much risk you would put yourself in if you were out-of-spec a bit, but I wouldn't chance it personally.
      - bangaladore 1y ago
        Could you not just run a 240 volt outlet on existing wiring built for 110v? Just send l1 and l2 on the existing hot/neutral?

by jchw 1y ago

cosmic_cheese 1y ago

Where things get hairy are old houses with wiring that’s somewhere between shaky and a housefire waiting to happen, which are numerous.

kube-system 1y ago
Yeah, but it ain't nothing that microwaves, space heaters, and hair dryers haven't already given a run for their money.
- jchw 1y ago
  Hair dryers and microwaves only run for a few minutes, so even if you do have too much resistance this probably won't immediately reveal a problem. A space heater might, but most space heaters I've come across actually seem to draw not much over 1,000 watts. And even then, even if you do run something 24/7 at max wattage, it's definitely not guaranteed to start a fire even if the wiring is bad. Like, as long as it's not egregiously bad, I'd expect that there's enough margin to cover up less severe issues in most cases. I'm guessing the most danger would come when it's particularly hot outside (especially since then you'll probably have a lot of heat exchangers running.)
jchw 1y ago
As an old house owner, I can attest to that for sure. In fairness though, I suspect most of the atrocities occur in wall and work boxes, as long as your house is new enough to at least have NM sheathed wiring instead of ancient weird stuff like knob and tube. That's still bad but it's a solvable problem. I've definitely seen my share of scary things. I have a lighting circuit that is incomprehensibly wired and seems to kill LED bulbs randomly during a power outage; I have zero clue what is going on with that one. Also, often times opening up wall boxes I will see backstabs that were not properly inserted or wire nuts that are just covering hand-twisted wires and not actually threaded at all (and not even the right size in some cases...) Needless to say, I should really get an electrician in here, but at least with a thermal camera you can look for signs of serious problems.

atonse 1y ago

You can always have an electrician install a larger breaker for a particular circuit. I did that with my "server" area in my study, which was overkill cuz I barely pull 100w on it. But it cost nearly zero extra since he was doing a bunch of other things around the house anyway.

davrosthedalek 1y ago
Larger breaker and thicker wires!
- atonse 1y ago
  I thought you only needed thicker wires for higher amps? Should go without saying, but I am not a certified electrician :-) I only have a PhD from YouTube (Electroboom)
  - jchw 1y ago
    The voltage is always going to be the same because the voltage is determined by the transformers leading to your service panel. The breakers break when you hit a certain amperage for a certain amount of time, so by installing a bigger breaker, you allow more amperage. If you actually had an electrician do it, I doubt they would've installed a breaker if they thought the wiring wasn't sufficient. Truth is that you can indeed get away with a 20A circuit on 14 AWG wire if the run is short enough, though 12 AWG is recommended. The reason for this is voltage drop; the thinner gauge wire has more resistance, which causes more heat and voltage drop across the wire over the length of it, which can cause a fire if it gets sufficiently hot. I'm not sure how much risk you would put yourself in if you were out-of-spec a bit, but I wouldn't chance it personally.
    - bangaladore 1y ago
      Could you not just run a 240 volt outlet on existing wiring built for 110v? Just send l1 and l2 on the existing hot/neutral?