Generator subpanel

[cj7jeep81]

I am wanting to set things up so that using my generator during a power outage is less of a pain. It's a smaller generator (6500 watts, 8500 surge), so not looking to power my house or anything, but would like to get away from running extensions cords through the windows/etc.

When I ran electric to my shed, I added some 1" conduit for a future generator, and ran the other side to my house. My plan was to put a weather tight receptacle on the shed that I could plug the generator into, then run wire into my basement to a new subpanel. This subpanel would then feed a handful of new outlets (basically the critical stuff of my sump pump, aquarium pumps, and maybe the fridge). The plan would be in the event of a power failure, fire up the generator, and plug it in. Then swap whatever I want to power to the generator feed outlets, and be good.

The problem I'm running into is wire size. My generator has a 30 amp twist connector, and ideally I'd hook up to a 30 amp receptacle on the shed. However, these receptacles can only handle 10 gauge wire, whereas all the subpanels I'm seeing take 6 or 8 gauge as a minimum.

Is it possible to feed a standard 100 amp panel with 10 gauge wire safely? The only other option I can think of is using a 50amp receptacle (and wiring it all up with heavier wire), and then using a 50amp to 30amp RV conversion plug, but I'd rather not do that.

 

[pattenp]

First, how are you isolating/locking the service from being backfed from the generator? Are you using a transfer switch or breaker interlock?

You can feed the 100A panel with 30A using #10, that's not a problem. How far is it from your shed to the house? You may need to up size the generator feed wire to #8 and use a 50A inlet.

Edit: Never mind my question about the transfer switch or breaker interlock. I reread and see you are installing a separate panel that is isolated from your house service. But why not run the gen wire to your house panel and use an interlocked breaker?

*

 

[cj7jeep81]

This is a 100% seperate panel from my main house panel, there will be absolutely nothing connecting it to the power pole. Distance from shed to where I'm wanting to put the panel is under 100', probably closer to 75'.

Does it matter then that the specifications on the subpanels say that the main lugs are rated for 6 gauge to 2/0 wire? This is for a standard homeline 100amp 12 space panel. I figure I'd only have 2 or 3 circuits (just to logically split stuff up).

 

[pattenp]

Yes that's a problem if the lugs are listed for wire no smaller than #6. Use a smaller panel.

This is a 100% seperate panel from my main house panel, there will be absolutely nothing connecting it to the power pole. Distance from shed to where I'm wanting to put the panel is under 100', probably closer to 75'.

Does it matter then that the specifications on the subpanels say that the main lugs are rated for 6 gauge to 2/0 wire? This is for a standard homeline 100amp 12 space panel. I figure I'd only have 2 or 3 circuits (just to logically split stuff up).

 

[pattenp]

Use something like this.

http://www.homedepot.com/p/Siemens-...0SU/100138862?N=bm2wZ12ky?NCNI-5#.UovEXdJONY4

 

[cj7jeep81]

Yeah, I hadn't thought of using the really small ones. 4 circuits would be plenty, since it's only being fed with 30amps. And since this is only going to be used a couple times a year (hopefully), there's not sense in spending a ton of money on it.

Thanks!

 

[pattenp]

Use a proper power inlet for the generator. Don't use an outlet and have to make up a gen cord with plugs on both ends.

http://www.homedepot.com/p/Reliance-Controls-30-Amp-Power-Inlet-Box-PB30/202213702#.UovMB9JONY5


*

 

[cj7jeep81]

Looking at this one at Lowes.

Most expensive part looks to be buying a cord. Holy **** those things are expensive. And I really only need one that's like 10' long, since the receptacle is already away from the house.

Looks like the link didn't work for whatever reason. Model # is T030N. GE 30 amp generator power inlet box.

 

[pattenp]

I don't know what the deal is with posting links from the Lowes web page. They never go to the right page. Anyway, that power inlet is fine. I like the ones where the cord hangs down or plugs in the bottom. Actually, I don't like the type that I posted the link to at HD.

 

[cj7jeep81]

Yeah, I like how that one allows the whole thing to close when plugged in. With the price of the cables, I'm now rethinking even using the conduit I buried. I could mount the inlet box on the side of the house (just under my deck), and run a short bit of 10 gauge straight down to the panel in the basement, and a 40' generator cable. Might be cheaper than a 10' generator cable, and 50' or so feet of 10 gauge.

 

[Charles (in GA)]

I haven't finished the project yet, but did install a Square D interlock on my Square D QO panel in the house and installed the power inlet box under the back porch, Got to finish running conduit and pull the wire.

I got lucky on cable for the generator. Went on CL one Sunday as I was leaving work, and searched for "SOOW 8/4". Now who would have ever though that I'd get any hits on that!!!!! Guy out west of town had some listed. Turned out to be two pieces, one about 45 ft or so and one about 38 ft, new cable, for $100. I bought a lot of four P&S male ends for $25 inc shipping in the packages, off of Ebay, and two Bryant female ends for $10 each inc shipping from an Ebay seller. Could not have got much cheaper.

Install a 30 amp breaker in the panel (with appropriate retainer for a main breaker) and the breaker will handle the #10 wire. Backfeed that independent panel thru the breaker.

Charles

 

[theoldwizard1]

When I ran electric to my shed, I added some 1" conduit for a future generator, and ran the other side to my house. My plan was to put a weather tight receptacle on the shed that I could plug the generator into, then run wire into my basement to a new subpanel.

Just to be clear, the generator receptacle is have NO CONNECTION to anything in the shed, correct ?

View media item 35231
You just want to park the generator out there !

Save yourself a lot of hassle. Add a generator interlock to your main panel and wire the feed from the generator into the main panel.

Most panel manufacturers make interlock kits and there are also 3rd party kits available.

 

[cj7jeep81]

Correct on no connection to the shed (wiring wise). The receptacle will just be mounted there, and it's an easy spot to put it somewhat away from teh house.

I really don't want to do an interlock kit, as I would have to move several breakers around to get it to fit, and with the generator only supply 30 amps, it will barely run anything in the house. My house is 100% electric, so it won't be able to supply the furnace, water heater, stove, etc. so not much point in tying the whole house to it.

 

[Scott P]

I bought my transfer panel on ebay. It was Honda labeled, but made by someone else, Pro-Tran maybe. I found it very easy to install and with my ten circuit model, I can connect enough circuits to make the house livable. Here in Houston, it's more of a concern for hurricane aftermath rather than cold, but at leas I know I know I can power a gas furnace if we got a freak ice storm.

I was actually quite surprised how quickly I filled up ten slots. Lights are on a separate circuit than the rooms, so it can take a couple circuits to power a room.

 

[pattenp]

I have an all electric house and I use an interlock with a 7500 watt gen. Yes, I can't run the big stuff, but it gives me the flexibility to flip on different circuits for lights, refrig, microwave and most important the TV.

 

[cj7jeep81]

Ok, I'll look at the interlock kits, and see how much of a pain it would be to move around a few circuits. I'd have to run some new ones, as my basement is on a subpanel that isn't fed from the panel upstairs, and would need some new outlets for down there, but it would be a cleaner set up.

 

[theoldwizard1]

I really don't want to do an interlock kit, as I would have to move several breakers around to get it to fit, and with the generator only supply 30 amps, it will barely run anything in the house. My house is 100% electric, so it won't be able to supply the furnace, water heater, stove, etc. so not much point in tying the whole house to it.

Water heater, stove, dryer, no. Read below

I have an all electric house and I use an interlock with a 7500 watt gen. Yes, I can't run the big stuff, but it gives me the flexibility to flip on different circuits for lights, refrig, microwave and most important the TV.

This is the whole point !

Yes, it might take a few brain cells to properly utilize a generator wired into your main via an interlock, but the FLEXIBILITY is the bonus !

 

[theoldwizard1]

Ok, I'll look at the interlock kits, and see how much of a pain it would be to move around a few circuits.

Pull the 2 breakers where the generator feed/interlock will be. Install a 30A 240 breaker. pul the next 2 breaker and replace them with tandem breakers.

I'd have to run some new ones, as my basement is on a subpanel that isn't fed from the panel upstairs, ...[/QUOTE]

I'm confused !

How about a simple diagram showing the meter and how all breaker panels in your home are connected.

 

[cj7jeep81]

Not quite that easy. The breaker where the interlock goes feeds my furnace, so it's already a double breaker, so can't just replace with tandems. Will just need to open the panel, and see how much extra wire they left me.

I have 400amp service to my house, which is split to 2 200amp panels outside. These panels have teh 200amp breaker installed, and then have I think 4 more spaces below them. When I wired my basement, I installed a 100amp breaker in this outside panel, and ran the wire through the wall and into the basement panel. This was a lot easier than trying to snake the wire up from the basement, and into an already 60% full panel. In effect, if I turn off the main breaker on the inside 200amp panel, my upstairs is off, but the basement is on. If I go outside and turn off the 200amp breaker that feeds the house, the house and basement are off.

In order to have the interlock kit do everything I need, I would need to run a new circuit or two from the house panel, into the basement.

 

[theoldwizard1]

Not quite that easy. The breaker where the interlock goes feeds my furnace, so it's already a double breaker, so can't just replace with tandems. Will just need to open the panel, and see how much extra wire they left me.

No sweat ! Splices inside the panel box are legal !!

I have 400amp service to my house, which is split to 2 200amp panels outside. These panels have teh 200amp breaker installed, and then have I think 4 more spaces below them. When I wired my basement, I installed a 100amp breaker in this outside panel, and ran the wire through the wall and into the basement panel.

I don't think you can connect the generator to the basement panel, or if you do, it can only feed branch circuits from that box. However, you could run the wire through the box to the main panel if that is the easiest path.

The real problem is with effectively 2 main panels, you can connect the generator to only 1 of them !

 

[pattenp]

This may be crazy, but why couldn't the gen power be split to both panels and have an interlocked breaker in each panel?

 

[cj7jeep81]

This may be crazy, but why couldn't the gen power be split to both panels and have an interlocked breaker in each panel?

I can see that as a possibility. But at the same time, this might all be overkill for what I'm wanting

My #1 goal is to not have to run extension cords through windows during a power outage, and hopefully fewer extension cords in the house. An interlock kit makes things more convienent during an outage, but typically, we have 1-2 outages a year. Most of them last less than 6 hours, and I think the longest was a little over a day. I'll probably just go with my original plan, of wiring up a 100% seperate sub-panel (using a small panel like pattenp suggessted), and running a couple outlets off it to power things. Should cost under $200 for everything (panel, power inlet, generator cord, wire, etc), and satisfy my main needs.

If I want to go the interlock route in the future, I can always do that. I'll just make sure teh panel I get has at least 4 spaces, and then I could pull the breakers for the circuits I ran, replace with 2 30 amp double poles, and run each to the 2 panels in the house with interlock kits. Really wouldn't cost any more doing it that way vs doing the interlock route in teh first place. Just some extra 12 gauge wire and some outlets (both of which I have at the house laying around).

 

[yetibiker]

Get a QO main lug panel. Tap #8 wires right off your main panel bus and run them into the new QO panel mounted adjacent to your main panel through a 1.5" ****** and terminate on a 2 pole 30A breaker. Don't forget the Neutral and ground and install a separate ground bar. In the spaces directly under the first 30A breaker, install a separate 2 pole 30A breaker and a breaker handle interlock between the two. Run #10/3 romex to your generator inlet from this breaker. Select which loads that you would like to transfer to generator backup power and remove them from their breakers in the main panel. Splice on to these wires to extend them through the 1.5" ****** and land them on properly sized breakers in the new panel.

It is a lot easier to buy the interlock plate kit if you have a compatible main panel, and just have everything transfer. You would be surprised at what 30 amps will run. Just because your range has a 50A breaker doesn't mean that cooking a meal on a burner OR in the oven is out of the question. You just have to watch what you are doing at the same time. The worst thing that will happen is the breaker on your generator , or in the new panel will trip.

An electrician around here would charge less than $700 in the moonlight all labor, parts, even the generator cord, included, maybe less if the inlet is close.