Plug generator into existing 240w plug?
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mike93lx
ALLIANCE MEMBER
No, absolutely not. That is a dangerous back feed.
You need an interlock with a dedicated inlet.
You need an interlock with a dedicated inlet.
What makes it dangerous if the main is turned off? Genuine question because doesn’t the interlock simply prevent back feeding into grid potentially shocking a lineman? I would certainly have the main shut off. Edited to add, I’m not at all opposed to getting an interlock installed, may even be able to do it on short notice I was just wondering if all they do is prevent back feeding the grid or otherwise causing a fire if the power back back on and main was on.
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nadogail
Well-known member
The cables, with two male plugs, used to connect generators to receptacles should be classed as a Lethal Weapon and their use considered a Felony Violation of the Electrical Code.
readhead
Well-known member
Suicide cords as they are often called.
yeah, you've got a 6-50 receptacle there . no neutral . you need a neutral to sun 120v stuff. and as mentioned, what you're doing is called a suicide cord. not recommended ,not kosher, and potentially dangerous to line workers. turning the breaker off ... yes, but it's not fail safe and very easily a mistake can be made .
Lassen Forge
Well-known member
Second question first - YES!!! Stupid and or suicidal. Just... don't.
PLUS you're feeding the house backwards through a 40 amp breaker... and hoping that main breaker doesn't go south and backfeed into the system...
People don't understand - you're "only" backfeeding 240 volts into the utility mains... so not that bad... except the lineman is working on the OTHER side of that transformer, so he's (or she's) dealing with 7200 volts... or 12KV... or whatever. Oops, guess the breaker didn't kill the legs" would sound awful bad at someone's funeral.
It looks fun on the house insurance claim also... "I didn't think he panel would short out and catch it on fire" isn't much of a defense when they say "claim denied"....
Seriously, wire the thing in right or don't do it. . Don't mickey mouse this.
PLUS you're feeding the house backwards through a 40 amp breaker... and hoping that main breaker doesn't go south and backfeed into the system...
People don't understand - you're "only" backfeeding 240 volts into the utility mains... so not that bad... except the lineman is working on the OTHER side of that transformer, so he's (or she's) dealing with 7200 volts... or 12KV... or whatever. Oops, guess the breaker didn't kill the legs" would sound awful bad at someone's funeral.
It looks fun on the house insurance claim also... "I didn't think he panel would short out and catch it on fire" isn't much of a defense when they say "claim denied"....
Seriously, wire the thing in right or don't do it. . Don't mickey mouse this.
johnre
Well-known member
I mean no offense, but if you have to ask this question, you probably should be looking into hiring someone with the proper knowledge and skills to do this job correctly.
Stuart in MN
Well-known member
There needs to be a failsafe method (in other words, a mechanical interlock) that only allows a generator connection when the main is off. You can say the main will always be disconnected first, but when you're half asleep at 3am in the middle of a storm that may not happen. Another reason is connecting the generator to this receptacle would require what's commonly called a suicide cord, with a male connector at the end that's hot.
Thanks for the good info that’s what I needed to know and didn’t think about. I found they do make an interlock for my breaker but the info about the 6-50 makes sense there is no neutral so either way I would need to pull 4 wires out here.
For what it’s worth I ended up putting in a service call with my electrician to install a transfer switch and an interlock. The interlocks I’m seeing online are just simple mechanical devices that don’t allow you to have the main and generator breaker flipped at the same time. Unless there is a more rigorous type that actually cuts the main off completely from the house with a safety disconnect switch of some kind.
mike93lx
ALLIANCE MEMBER
A interlock kit is just that. A simple physical barrier made from sheet metal.
You can put in a transfer switch upstream that is more complex but it's also much more expensive.
I put reliance controls main panels in my last two houses that had integrated three pole transfers built in and forced turning off the main to use the generator. If I was doing a main panel swap anyway, I'd consider using one again. In my current house, i have two main panels that are new enough, so I installed an interlock in one and moved over anything that I want backed up to that panel.
Lassen Forge
Well-known member
There are - a transfer switch (at least here) is what's considered standard, and mandatory to connect to your local system. Even our winky squinky back up generator has one - it monitors your voltage input from the mains, if it goes dead, it physically unhooks you from the "grid", fires off the generator, and then connects the generator to the building wiring. If the mains connection doesn't "break" it won't allow the generator to start. IIRC it was MAYBE $500, probably less.
Once the mains power comes back on line, it confirms your power is on, Confirms you are "in phase", takes your generator off line (to cool down), and connects your system to the mains. In ours it happens so fast all we have is a 1 or 2 HZ "blink"... (takes way less than a second) The switch also detects brownout conditions, and dumps mains power and fires off until the brownout either ends or the power goes out.
We had an unusual situation before (during an electrical storm) where our power mains kicked on and off cyclically -- about 3x per second - for a few hours, which is why we got the genset. If that happens again, we kill the main breaker (at the PoCo connection & so-called "smart" meter) manually, and watch the neighbors lights to see if our supplier (ENEL) has stabilized or not. Cheaper than replacing appliances!!!
What they won't allow here is a sheet metal interlock (like the did in the states) because of the risk if that breaker panel effs up and does send energy back through a defective breaker. Plus the breaker panels here aren't condusive to such an interlock anyway...
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wyliesdiesels
Well-known member
Please do it proper. Your plan is not safe and wont even work with that 6-50r since theres no neutral
micromind
Well-known member
This is the best, easiest, most reliable automatic system available. Pretty much no maintenance and a lot of these switches have programmable controllers. The ones I install are mostly industrial models, some of them up to 3000 amps at 480 3 phase. But they all operate the same way.
The next step down is a manual transfer switch. This is a double-throw switch that is operated by a handle, nothing automatic. It will determine whether the utility or the gen will supply the load but never connect the two together.
Breaker locks (sheet metal interlocks) are a form of a manual transfer switch and they'll work provided they are not messed with too much. Basically, when the power goes off, you turn the main breaker off then turn the gen breaker on. This device will (usually) prevent both breakers from being on at the same time.
Using any sort of a double-ended cord to backfeed a panel is a pretty serious hazard. For one thing, it depends on remembering to turn off the main before plugging in the gen. Yep, no doubt.....I'll remember every time.......
Also at some point there will be cord plug prongs that are energized. It would be very easy to unplug the cord at the gen when you turn it off and forget to unplug the cord from the house. This will result in the plug prongs being energized at the gen end.
The main purpose of every transfer switch is to make it impossible for the utility and gen to be connected together.
75gmck25
Well-known member
There is another type of interlock that reroutes a set number of circuits (usually about 6-10) through an external switch that is connected to the generator, and it is used to switch those circuits between generator and commercial power. Its not really that much more complicated to install if you don't mind some quality time with wire nuts, and its more flexible than other options.
This is the type of switch I am talking about. I don't know anything about this brand and its quality.
www.maxtool.com
This is the type of switch I am talking about. I don't know anything about this brand and its quality.
Reliance A510C 120/240-Volt 50-Amp 10-Circuit Pro/Tran 2 Indoor Transf
Features Pro/Tran 2 50-Amp 10-Circuit 120/240V Manual Transfer Switch The next generation of Loadside manual transfer switches (6) 15A 1-pole, (1) 20A 2-pole, and (1) 30A 2-pole Safest Way to Distribute Power Eliminates dangerous backfeeds and electrical overloads 10 Single-Pole Circuits or 5...
www.maxtool.com
Insurance companies are in the business of paying for stupidity. If you burn your house down because you're a knucklehead, they'll pay the claim, just the same as if you did something stupid and burned your house down. You may find it difficult to obtain insurance after, of course.
Lassen Forge
Well-known member
Installing unauthorized devices contrary to building codes (and/or without required permits), dangerous modifications to a structure, and even (yes) illegal activity in a covered dwelling or structure are all valid reasons to deny a claim. And believe me, insurance companies are in the business of making money for their investors and shareholders... if they paid for stupidity, they wpouldn't be in business long.
wyliesdiesels
Well-known member
that isnt an interlock. its a manual branch circuit transfer switchThere is another type of interlock that reroutes a set number of circuits (usually about 6-10) through an external switch that is connected to the generator, and it is used to switch those circuits between generator and commercial power. Its not really that much more complicated to install if you don't mind some quality time with wire nuts, and its more flexible than other options.
This is the type of switch I am talking about. I don't know anything about this brand and its quality.
Reliance A510C 120/240-Volt 50-Amp 10-Circuit Pro/Tran 2 Indoor Transf
Features Pro/Tran 2 50-Amp 10-Circuit 120/240V Manual Transfer Switch The next generation of Loadside manual transfer switches (6) 15A 1-pole, (1) 20A 2-pole, and (1) 30A 2-pole Safest Way to Distribute Power Eliminates dangerous backfeeds and electrical overloads 10 Single-Pole Circuits or 5...
paranoid56
Well-known member
its done all the time, is it the best or correct way? nooope. do people do it in case of an emergency? sure they do
wyliesdiesels
Well-known member
huh? plugging a generator into a 240v receptacle is NOT done all the time because it doesnt work for 120v loads
Backwards? Like, which direction is AC current supposed to go?
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