NY Nick
NY Nick Dork
12/23/22 3:34 p.m.

I have a question about feeding my house from a generator. I do know before I even ask that what I want to do is considered wrong and dangerous. 
I want to back feed my panel through an outdoor outlet. 
before I start I would turn off the master breaker to not back feed the grid. I have a 4500 watt generator with 2 20A outputs. I have 2 circuits outside that are 20A each. I also have made 2 suicide attempts extension cords. 
1- turn off main breaker

2- turn off all breakers

3- plug in suicide cables

4- start generator 

5- energize breakers that outdoor outlets are on

6- energize breakers that I want to run in the house (leaving all 220 breakers off)

 

My main question/ concern; will having 2 breakers of 120V with up to 20A coming to the panel result in 120V with up to 40A of power available? I don't know if there is any phasing issues to think about or anything else (except for possibly back feeding the grid mitigates by leaving main breaker off and electrocution by grabbing the hot suicide cables WG I I will try very hard not to do)

Thanks

67LS1
67LS1 Reader
12/24/22 11:49 a.m.

You should really invest in an inexpensive manual transfer switch so don't hurt yourself or others.

As far as the distribution of the 2-20a, 120 volt circuits, you should try to keep the loads balanced on each leg. It doesn't have to be exact. 

Also, 20a is over the capacity of your average light duty extension cord. Make sure whatever cords you use are rated correctly.

My brother has a 4500 watt Honda and did NOT want to back feed his house so I built him a distribution box that has a 30 amp input receptacle, a 30 amp rated on off switch and 4 duplex outlets. He runs a heavy cord outside to generator and then normal cords from the box to whatever loads he needs in his small home.

lrrs
lrrs HalfDork
12/25/22 6:42 a.m.

In reply to 67LS1 :

Very cool. This is similar to what I am planning but never get around to doing. The difference is mine would be a window insert so no cracked doors or windows to run the feed cord through.  Open window, insert, close window down on insert. Connect feed on the outside, and feeds to the fridge, sump pump, and other necessities on the inside.

Dirtydog (Forum Supporter)
Dirtydog (Forum Supporter) Dork
12/25/22 7:41 a.m.

I had thought of back feeding my 10,000 watt into the house.  I opted to have a transfer panel installed.  Just a couple of steps, but I feel more comfortable with this. YMMV.

Tom Suddard
Tom Suddard Director of Marketing & Digital Assets
12/25/22 8:27 a.m.

No. Don't do it.

I installed a transfer switch in a few hours for about $300.

NY Nick
NY Nick Dork
12/25/22 11:10 a.m.

I built 30A extension cords. 
 

I understand the transfer switch and why that is preferred. 
 

all the transfer switches I see seem to be for a bespoke # of circuits and they get wired to those specific ones. I have  an old house that has a mish mash of outlets and rooms on different circuits. 
is there a switch that just allows the power to the main to be switched to the power from the generator and that's it?

SV reX
SV reX MegaDork
12/25/22 11:32 a.m.

What you have described will work. It's also illegal (which you know). NEVER, NEVER, NEVER turn on that main while it is connected. 
 

The worst part about not having a transfer switch is the possibility that someone other than you might start it and hurt someone. What if you are caught in a snowdrift and a family member starts it?

 

Picture an electrician  with his hands in the panel standing in a bucket of water while your hand is on the main breaker promising to not turn it on. THAT'S why you need a transfer switch. 

NY Nick
NY Nick Dork
12/25/22 11:51 a.m.

In reply to SV reX :

Fair points by both you and Tom and others before. I will follow the transfer switch path. 
Thanks to all of you for the advice. Sometimes you just need to bounce these things off other people. 

DrMikeCSI
DrMikeCSI Reader
12/25/22 12:27 p.m.

The simplest transfer switch would just disconnect your breaker panel  from utility power and then connect the panel to the generator. You don't need the ability to feed power to the utility like some solar power systems have. 

67LS1
67LS1 Reader
12/25/22 6:49 p.m.
DrMikeCSI said:

The simplest transfer switch would just disconnect your breaker panel  from utility power and then connect the panel to the generator. You don't need the ability to feed power to the utility like some solar power systems have. 

Yes, a simple double throw safety switch would work. You could add a cord receptacle to the enclosure and not have to run extension cords at all.

The drawbacks to trying to feed say a 4500 watts to an entire house are:

A.) It should be 240v which is not typical in small portable generators. 

B.) You have to be conscious of what loads could be on and off in the house so you don't overload the generator. 

OHSCrifle
OHSCrifle UltraDork
12/25/22 7:40 p.m.
oppositelocksmith
oppositelocksmith Reader
12/27/22 12:02 a.m.

I worked in the generator business for many years for one of the largest companies (I ran an alternator factory). FWIW, I would not bother to wire a 4500 into a house. Really not enough power to keep a whole house going- why does this matter? Imagine trying to remind people "don't turn this or that on while I have this other thing on, or we'll overload it." The distribution box model saves those issues. Allows you to load manage the critical needs (furnace fan, fridge, etc) with appropriate cords.

My parents live in the middle of no where, with electric heat and above ground supply lines that run through forests. After a storm in 2008 that left my mom without power for several days, I helped buy them an 11kv gen. Dad had a manual transfer switch wired in for $500. The 11kv is enough to run 1 floor of their home without issue.

Toyman!
Toyman! MegaDork
12/27/22 8:06 a.m.

One of these will do what you want for about $50 and keep you from back-feeding the meter and utility pole. 

It will interlock the main and a top breaker on the panel. Feed the generator through the top breaker. Understand that without a 220 breaker and a jumper only half the panel will be hot. 

alphahotel
alphahotel New Reader
12/27/22 9:56 a.m.

I put something like this on our panel:

https://www.amazon.com/GE-200HDA-Electric-Generator-Interlock-Verticle/dp/B0163JD6SY

The generator is wired (in the above example) to the breaker at the top-left of the panel.  The interlock prevents the main and the generator breakers from both being on at the same time.  We had a manual transfer switch with only a few circuits on the panel when we bought the house, but it did not work in our case because we added an addition to the house with a 100-amp subpanel.  If I wanted to be able to run anything in the addition, I really need to energize the whole main panel.

You have to buy an interlock that is specific to your panel (the link above is for a GE panel).

[Edit: I typed this up before Toyman posted the same thing.  Sorry for the duplicate]

dculberson
dculberson MegaDork
12/27/22 10:13 a.m.

The previous owners of our house got rid of the automatic generator but left the wiring and switch. After I lived here for a few years with zero outages, I removed and sold the 100 amp automatic transfer switch on eBay for $200. I bet you could get a similar deal with a little patience and shopping. Mine had the breakers in a separate small sub panel but some have breakers in them. Seems worth it to avoid the danger of a backfeed setup.

dean1484
dean1484 MegaDork
2/11/23 10:56 a.m.
Toyman! said:

Understand that without a 220 breaker and a jumper only half the panel will be hot. 

This is not necessarily true. The legs should be alternated in the panel so you can use two 110 beakers next to each other with one leg of the 220 to each breaker. Thus you have 110 to each side of the panel. I have a similar set up in my panel with a lock out for the main if I want to swap the house over to my generator. 
 

EDIT:  I did not realize that the lock out plate only covered one side so yes use a 220 beaker with that lock out. Using two 110 ones would be incredibly un safe. 

DarkMonohue
DarkMonohue Dork
5/14/23 2:24 p.m.
dculberson said:

The previous owners of our house got rid of the automatic generator but left the wiring and switch. After I lived here for a few years with zero outages, I removed and sold the 100 amp automatic transfer switch on eBay for $200. I bet you could get a similar deal with a little patience and shopping. Mine had the breakers in a separate small sub panel but some have breakers in them. Seems worth it to avoid the danger of a backfeed setup.

Since you brought up a subpanel, it's an option for putting specific circuits on standby (generator) power. Re-route your critical circuits to the subpanel and then add an interlock to the subpanel to switch between utility power (i.e. subfeed from the main panel) and generator power. That way only those circuits served from the subpanel will receive power from the generator when in use. The main panel will be safely divorced from generator power and there's no danger of backfeeding the utility.

This was the simplest solution for me since my house is old and has a funky split-bus panel that doesn't have a single main breaker.

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