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Generator to house hookup

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179K views 216 replies 57 participants last post by  oldasrocks 
#1 ·
I've been told that you can plug a portable generator into one of your homes power outlets and it will power the homes other outlets.

The procedure was this: Run a line from the generator to one of your homes outlets after cutting the external power off at the homes main power box. You can then use the outlets in your home as long as you don't exceed your generators power rating.

Does anyone know for sure (especially one of you electricians) if this is true?
 
#2 ·
That is incorrect. Power has to be distributed through the main feed in the electrical panel. Now, you can hook up a generator and run it to the panel via a switch gear (switching the source from main power to generator power), which could send the generator's power through each circuit throughout the house that goes through that panel.
 
#8 · (Edited)
You can 'SAFELY' (Safe, but I didn't say up to code!) wire your generator into your breaker panel a couple of different ways...
The way you describe isn't one of them.

If you insist on using an extension cord (or two) just plug into the genset and run the cords in the house and plug in the essentials directly to the genset, Fridge, a couple of lights, cell phone charger, what ever else you might need to use....
------------

BUT,
To answer your question,
YES. You can simply run an extension cord from your generator using the traditional male plug and plug that cord into a standard outlet using a NON-Traditional male plug on the other end.

This is a BAD IDEA on may levels, but it will work.


First of all, an extension cord is just too small to conduct much current,
You run the very real risk of starting fires.

Secondly, The 'Male' end prongs sticking out on the house end are 'HOT'! This presents a very real electrocution hazard.

Third, With the current passing into the wall outlet, there is absolutely NO OVER CURRENT PROTECTION in the line anywhere!
Again, if you over tax that circuit, it has a real chance of heating up and catching fire!

For all practical reasons, you shouldn't consider doing things that way, and you should discourage others for even talking about it and spreading the idea!
 
#9 ·
This is what you will need for a connector since the contacts incoming will be 'Hot' and have to be protected,
AND,
The socket going into your electrical system will have to be protected also, since they stand a chance of being 'Hot'...

You might not need one this large, but you will need something very similar.
-------------------------------------
-------------------------------------

The safest way to connect your generator to a home breaker panel is with an 'Interlock' or 'Lockout'.

There are some different types, but mine looks like,
An electrical box you install before your main breaker box,
With two 'Main Breakers' side by side.
There is a metal bar that has a flat sliding 'Tab' on it that will only let you have one breaker 'ON' at a time.

One breaker is connected to the outside 'Grid' service,
The other is connected to the generator.

Very simple and practical, you simply CAN NOT have the Grid power and the Genset power on at the same time!
-----------------------------

This is a schematic/diagram of a 'Transfer Switch' for home generators.



And here is the web site I stole that from,
http://www.smps.us/transferswitch.html

Here are some sources, articles...
http://www.generatorjoe.net/ts.asp?gclid=CNzf09ewqpYCFQObFQodox2Ixg
http://www.ronhazelton.com/howto/home_generator_installation.htm
http://mayberrys.com/honda/generator/html/transfer.htm
http://www.gen-tran.com/
http://cvfsupplyco-store.stores.yahoo.net/mahogetrsw.html
http://www.steadypower.com/catalog/rc_intro.php?gclid=CISN1f2uqpYCFQIWFQodJ2jVyg
 
#10 ·
Suicide Plugs



What you are describing is called a "suicide plug". From Popular Mechanics,


13. RE: 4 Steps to Power Your Home When the Grid Fails
NEVER use a suicide plug. FIRST if you forget to turn off the correct breakers, you can KILL a lineman. if you reverse polatity you can KILL a lineman. if you fail to properly ground everything you can KILL a lineman.. it's nowhere reasonable to risk someone life so you can look cool, just run a cord if you don't have the proper transfer switch, installed by someone that knows what an isolated ground can do.


A better solution is to have an electrician wire a transfer switch to your service. That will keep the lineman safe.

Thanks for bringing this question to the table.
 
#11 ·
Now, if you are really cheap ba$tard and you want to wire you home for a temporary generator in an emergency situation,

This only works with small, 'Portable' Gensets, and this IS NOT the 'Proper' way to do things, and it's NOT TO CODE!
----------------------------

TURN OFF THE MAIN BREAKER AT THE 'TOP' OF THE PANEL!

Get yourself a 30 amp side-by-side breaker intended for a 220 volt appliance, like a water heater, ect.
And leave it OPEN (nothing connected to it) in the breaker box.
LEAVE THE BREAKER TURNED 'OFF'!
---------------------------

BUY AND STORE WIRE LONG ENOUGH TO REACH FROM THE GENERATOR TO THE FUSE PANEL,
AND BUY A 220 VOLT PLUG (Male) THAT FITS YOUR GENERATOR.
Virtually all the generators larger than the suit case size ones have a 220 volt outlet, make sure your plug fits that outlet.

USE AT LEAST 10/3 GAUGE WIRE!
That means 10 Gauge conductors, 3 insulated Conductors, and a bare earth ground wire.
Flexible wire is MANDATORY if you are going to use the generator for longer than a few days,
Solid wire is OK for a day or two, but the generator vibration will eventually stiffen and break the wire conductors.

Install the plug on the wire.
Wiring options will be...

Black, Red, White, Bare.
Black & Red are conductors, or 'Hot' legs and connect to the two breakers you installed in the box.
White is 'Neutral' and will need to be connected to the bar in the breaker box where the other 'White' wires are.
Bare will be EARTH GROUND, and must be connected to an EARTH GROUND ROD.

Black, White, Green, Bare.
Black & White are conductors, or hot legs and connect to the two breakers you installed in the box.
Green would be the 'Neutral' and gets connected to the same place in the box as the 'White' wires from other circuits,
Bare would be the Earth Ground.

When you have turned 'OFF' the main breaker,
Then, and ONLY THEN, do you start the generator,
And then you can turn the double breaker you installed in the box on for power to your panel.

If you EVER turn the main breaker on with the generator attached to the system, you stand a very real chance of electrocuting line workers trying to fix the power,
AND,
As a double bonus, you stand a pretty good chance of burning your house down or burning the generator up right where it sits!

BOTH MUST BE OFF BEFORE THE OTHER IS TURNED ON!
AND BOTH CAN NEVER BE ON AT THE SAME TIME!

I don't recommend this, it's dangerous, not up to code and I'm NOT trying to sell it as a home game!

If you don't fully understand how the breakers and electrical system works, DO NOT ATTEMPT THIS!
 
#12 ·
I do appreciate all the replies from everyone. FWIW, the first reply from Denny was all I really needed to know. I'm already aware of the problems tapping into a household circuit from a second power source can cause (possible fire, overloading the circuit/generator, possible danger to linemen, etc) which is why I haven't tried this method. I really just wanted to ask around a bit and get second opinions before talking to a professional electrician.

Anyway, up to now I've simply run extension cords to the items I wanted to power with my generator and will probably continue to do the same in the future, at least until I can have an electrician give me a price for wiring my fuse box to accept a generator.
 
#13 ·
That's all right, the added responses might have answered someone else's questions, or inspired some though in someone for a good idea or two!
 
#18 · (Edited)
Is there any danger of frying the circuits if you have the generator hooked up to come out of the outlets and the power came back on?
Not if you disconnect the main breaker in the breaker box before doing ANYTHING else with the generator.
------------------------------

Not if you use a switchgear. But there's always the possibility of surges while on gen power. It's not a regulated flow like from the transformer on the power line.
Generators are pretty good about keeping the 'High' voltage limit from exceeding safe limits, so 'Surges' aren't really the big deal with generators...

What Generators usually have problems with is 'Brown Outs' when the small generator engine stumbles or sputters, RPM's will slow, and production will drop...
Things go 'Dim' and we call it a 'Brown Out'!

Also, Production should be around 60 Herts, or 60 Cycles per second...
That's AC or Alternating Current switching polarity 60 times a second, or there about...

That cycle can swing when the generator slows down or speeds up, so it's usually a good idea NOT to run sensitive electronic equipment directly off of a generator...
Use a power filter like a battery back up unit that will 'Smooth Out' the problems in the power before it gets to the sensitive equipment.
 
#19 · (Edited)
What you are describing is called a "suicide plug". From Popular Mechanics,


13. RE: 4 Steps to Power Your Home When the Grid Fails
NEVER use a suicide plug. FIRST if you forget to turn off the correct breakers, you can KILL a lineman. if you reverse polatity you can KILL a lineman. if you fail to properly ground everything you can KILL a lineman.. it's nowhere reasonable to risk someone life so you can look cool, just run a cord if you don't have the proper transfer switch, installed by someone that knows what an isolated ground can do.


A better solution is to have an electrician wire a transfer switch to your service. That will keep the lineman safe.

Thanks for bringing this question to the table.
Refer to the info I posted in Types of Generators

If a backup generator is to be connected to a building electrical service, NEC requires that it be equipped with a double-pole, double throw transfer switch. If you fail to do so and a utliity worker is killed due to your negligence you are both civil and criminally liable.

Be stupid, go to jail, go directly to jail, do not pass go, do not collect $200.
 
#20 · (Edited)
OK WE GOT IT...
You found the NEC code and cut & pasted it.
-----------------------------

Now, for the rest of you out there,

Disconnect the main breaker at the 'Top' of the breaker box, and use a 30 to 50 amp breaker in the box to connect a generator to you home...
IN THE EVENT OF AN EMERGENCY.

I strongly recommend you follow the links I posted on page 1 of this thread, to the proper manual and automatic switching,


But in the event of devastating natural disaster, like when tornado or hurricane removes the electrical grid virtually completely, and you have access to a generator, then you can 'Sneak' a circuit into your box SAFELY...
Just remember the Mains MUST be removed, or the meter must be removed to make it 'Safe'...
 
#21 ·
When I get a generator, I will use a Break Before Make maintenance bypass switch for a UPS. My primary feed will be utility, and I will switch to generator feed manually when the need appears. I should be able to find a used bypass switch at work.
 
#22 ·
I wish I could find a reasonably priced transfer switch application that would work.

Right now, I throw the main breaker in the box, then run my Genset on a 220v 50 Amp breaker in the service panel.

I just keep a security tab over the Genset breaker to make sure no one turns it on by mistake.
Security tab has a big warning to turn the main off before engaging the Genset.
---------------------------

Our big generator in Fla. has a 'Ship To Shore' switch out of a boat, that defaults to the generator when inactive, but switches over to Grid power when there is Grid power.

I'm not crazy about that arrangment since the Switch draws power at all times when there is grid power to keep it engaged.

It's NEC compliant and works well, I just wonder how much current it's taking to keep the switch active?
--------------------------

Our little river house has a Genset and solar panels, and it has a manual transfer switch built into the system.
Flip the switch and fire up the Genset/welder to work if you need more power than the panels can supply.

Eventually, we'll have a battery bank to supply supplement the solar, but I haven't got that far yet...
 
#24 ·
Here is something else to think about when you want to use a generator for part time/ emergence use . Use extra heavy duty extension cords and try to keep them as single runs from gen to appliance(s) in use. I suggest either 12/2 or 10/2 cable that way the cables won't heat up if to much current is drawn threw them.
 
#25 ·
there was an item i saw at loes today.
it lets you hook up your generator to your fuse box, looks amazingly simple.
it was like 250$
Yup, manual transfer switch isn't too bad to install, they just cost a lot.
I'd like to find a common application where they were used were we could get them for say $50 or so...
 
#26 ·
Almost any business with a 10-15KVA UPS will have a bypass cabinet. You may be able to get one from a business that is shutting down. I've decommissioned dozens of UPS from grocery stores. Just make sure that the switch is Break Before Make and not Make Before Break.
 
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