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this post was submitted on 25 May 2024
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What the actual fuck?
Disqualified.
First part is classic stuff right?
Yeah. My grandfather (former electrician and electrical inspector) had a specific outlet he’d plug a gas generator in to back feed power into the house. This was in the 80s and 90s.
He also pointed out that he turned the main off so it did not back feed into the grid and power lines that a lineman is expecting to not be live.
From the article:
But isn’t a power outage the time you need it?
I think its more that you can supplement you normal power draw so your electricity bill isint so high
Transfer switch is the proper tool for this and is a fairly simple install.
Yeah my parents house had an rv/generator hookup and it had a huge bar across both the breakers so power could only flow in one direction. If you hooked up a generator it would cut the house off from the mains.
Your grandfather's extra outlet for the alternate feed was the other half of a switch that flipped over when the mains power died. It shuts off the power connection to the house by flipping over and ensures no power goes back over the line, among other things. We have these - albeit the size of a washing machine - in really big datacenters.
If you're gonna do dumb shit, do it smart
Yes as your granddad points out, you can’t just plug a power source into any old outlet at any time. Selling a system like this on Amazon to apartment dwellers seems to encourage just that behavior.
Should not be via a standard wall jack. As far as I know.
Depends on electrical code which depends on, most of all, your standard plugs. In Germany Schuko is deemed non-optimal, but acceptable, for up to 800W.
...no issues regarding exposed prongs, if the inverter doesn't see AC to sync to it doesn't output anything. It's not a dumb spinny magnet generator we're talking about here.
Most people don't have an outlet on their balcony, though, and weather-proofing the thing is an issue in any case so while you're at it you can just as well put in a proper Wieland outlet. 20 bucks or so, the expensive part will be the electrician not the outlet.
In the UK our everyday plug is rated for 13A - nearly 3KW. The plug on my phone charger is the same as the one on my tumble dryer and I don't know if that's a good thing or a bag thing.
Schuko is rated for 16A continuous for one hour, 3680W, I think the UK plug would actually take quite a bit more you're just being conservative. Or something odd about ring circuits I don't want to think about.
In any case practically nothing in a household actually uses 3kW. A stove, yes, but that's connected to three phases and without a plug (usually 3x20A over here -- CEE plugs can do that but they're chonkers and how often do you move your stove). Newer dryers should stay under 1kW, the standard high load appliances are kettles and hair dryers.
Eh, that's pretty standard where I live. Didn't even know there were non standard wall jacks lol
I’m also against proprietary systems but is there an open alternative?
What's wrong with that? That's how basically any balcony solar system works.
The cables in your walls are designed for a certain maximum current before they start to heat up. This current is limited by your breaker.
Now if you introduce a plug in solar setup your current is limited by your maximum breaker capacity + whatever your solar setup can generate.
So if I'd use the specs from the article and apply it to a normal dutch home situation: 16A breaker, + 800W at 230V, which means ~3.5A = 19.5A max. which is probably still fine for short durations.
But now some genius doesn't read the fine print and hooks up 2 or 3 on the same circuit. There is no electrician that tells him that's dangerous because it's all self installed and he doesn't know any better. And all of a sudden you are up to 26.5A and you got glowing, smoking wires in your walls...
Ok sure, that makes sense. This might actually be an issue.
Also, emergency service hazard. The PV won't turn off if firefighters take out the mains, which makes a house potentially inaccessible during an emergency.
Surprisingly, no. Most inverters in the EU must come with island protection. Meaning that if there is no AC from the grid it immediatly switches off the inverter or the battery, there is no stand alone operation.
There are some systems that allow it but they are rare here and require the mains side to be fed trough the inverter itsself ensuring it's never back feeding into the grid when there is no power with the same island protection, or less commonly there is a transfer switch of some kind also eliminating the issue. And either should obviously have a main kill switch on the breaker board for emergencies that also switches off the in home power with 1 action.
But most importantly, either of those options is not plug and play and will require an electrician that hopefully does know what he's doing.
Does the island protection with if you have two inverters running independently? (legally or not)
Yep, I'm not exactly sure on the technical details but it works with multiple inverters. Otherwise having a street full with solar panels on every roof would still be a hazard if the power went out at a distribution junction for said street and repairs would have to be made.
If there is no powerplant feeding some energy, all inverters should shut off. Fixed installs and plug and play variants alike. I'm actually amazed that there are parts in the world where this isn't common.
Yes, because the frequency of the grid is also a trigger for shutting off the inverter. Inverters generate a frequency which indicates a "non healthy grid" that trigger the shutoff of connected inverters.
I looked into these before and believe the inverters shut off if the mains shuts off. The DC side of the circuit would still be potentially dangerous though.
The inverters need there to be power in the mains circuit because they convert DC to AC and match the phase of the AC power they are generating to the mains supply.
Your breaker will pop. Just like if you were to run a hair dryer on each outlet.
The breaker only sees the current flowing through the breaker though. Not the additional current provided by the solar panels since those don't flow through the breaker. So it will pop later then that the cables are rated for, therefore introducing an overheat and fire hazard.
That happens quite a bit in a lot of areas. It sounds stupid but your toaster does not care where the electricity it is using comes from.
As long as the sine waves are in sync with each other then you have nothing to worry about.
It's probably not standard in America because the technology is newer and the regulations haven't caught up.
2 problems….
If you forget to turn off the mains, it could really make a lineman unhappy.
Most of these setups require a reprimand dangerous “ suicide cord”
The first problem is solved by line sensing technology. If there is not power coming in and off of the switch then the inverter will not pump energy back into the system, at least on the ones that are not $12 cheap Chinese junk off of taobao.
And rather than suicide cords they generally have an IEC connector (standard rhombusy shaped computer power connector) on one end and a normal prong on the other.
But you are right that it is dangerous and not recommended to anyone, especially the people that are not smart enough to take the appropriate concerns and considerations into mind before using it.
I’d be super disappointed by owning a solar cell and not being able to use it during a power outage.
That's a pretty standard issue with grid tied solar systems. You save a lot of money by not having batteries, but when the neighborhood goes down you go down with it.
Plus you don't want to be pumping electricity into a downed power system, you could actually end up hurting a line man who is working on the system.
However, and both of these issues can be resolved by adding in a generator and a whole house cut off system.
In a power outage scenario, all you would have to do is throw the crossover switch and crank the generator. The generator would produce enough energy to reactivate the solar system.
Yea with solar and a transfer switch you only need a small battery powered inverter to kick on the solar juice
No need to run a generator when the sun is out
I know enphase micro inverters have "anti-islamding" tech that disables output when they lose grid connection. I would expect any reputable manufacturer to also have the same tech.
I don't expect that for backup generators, but the proper way for them is via a transfer switch. You can wire in a properly made cable instead of a suicide cable. The transfer switch would prevent the inlet connector to the house from ever being live. (And since it is a proper cord from the generator, there would be no exposed ends coming from it.)
I agree on all points, but honestly I’d be pretty upset if I got a solar setup that didn’t work when the power was out haha
There is still a solution for that, solar + battery. I would love to have one myself, but solar alone can be a bit expensive on its own.
Sure, but this solution isn’t that.
Yes it is if you read the article, that's exactly how he had it set up, and then you just have to manually move the battery where power is needed. You just can't use your wall outlets when there's an outage.
Whole house generators have been around for a long time and they are usually wired, at the junction, into a few specific lines to essential appliances like refrigerators because it’s hard to produce as much current as the grid on your own, and you want to spend what you can generate on site wisely. Trying to power your whole house through some bedroom outlet is not going to work well. Your TV will sit there sucking some of that power listening for your remote to turn it on while your lights will flicker and your fridge will chug chug chug and not stay cold.