Vinnys House of Real Estate

Getting a generator for your house is becoming more of a necessity these days. There are a lot on the market to choose from, and there are countless ways of hooking them into your house. I’ll talk a little about how I set up my home and why I choose the configuration.

Note: I am not an electrician (just a tinkerer), do not take any of my advice for fact and don’t hold me responsible for anything you do while messing with electricity.

Kinds of generators:

There are two main types of generators, portable and permanent. The majority of portable generators in the U.S. use gasoline as their fuel. The permanent generators can also use natural gas, propane, or diesel. Portable generators run up to about 8000 watts and the permanent variety can go much higher. Portables have wheels that let you move them around. They can be very heavy though, the 8000 watt I have is over 200 pounds. Not that portable in my opinion, but it does have wheels!

With permanent generators you can have them wired in for automatic transfer/cut-over. This way if you are not home, or do not want to setup a portable generator when there is an outage, your power will always be available. They typically require a larger gas inlet from your energy company, and have more of an involved installation (need a cement pad as well to put it on). These varieties will self-test to make sure they always work. A popular brand is Guardian. I have used the 15Kw version before and it works great.

Where to buy:

You can purchase generators online, and at any local home improvement store. I purchased mine at the Home Depot near my house. I choose to buy it locally in case there are any problems, I have a place to return it. With larger purchases (and heavier) things like generators, good luck returning them to an online retailer.

Sizing:

Generators are sized by wattage. A typical 3 bedroom home can use between 1000 and 5000 watts running the furnace, TV, refrigerator, and a PC or two. Every appliance is different, so try to add up the watts (from the manuals, you kept them right?) of everything you want during a power outage. Most likely you cannot use your oven if its electric, and your washer/dryers. They use a heck of a lot of juice.

A website that will assist you in this task is: AskTheBuilder On the page there are two columns, reactive load and resistive load. Reactive load is the peak power it will need and resistive load is the constant power it uses. Get a generator that can handle your peak and constant power loads.

If you are more technically inclined, you can purchase an amperage meter and measure the power output at the panel. Don’t blame me if you electrocute yourself! This is how I determined the power used at my house, running all the appliances and lights I wanted, I measured the amperage at the main breaker. It turned out to be about 10 amps, which is reasonable since most generators can output 30 amps. This figure doesn’t include my water pump and furnace which make it jump up considerably. I also wanted to be able to use my air conditioning in case of a mid-summer blackout. The AC unit uses at least 10 amps on its own, so that is about 20 amps so far.

I need to double that figure accounting for each incoming utility line (there are two 120 volts coming into your house), so using the equation (Watts = Amps x Volts) I have about 40 * 120 = 4800 watts needed. I am making a lot of generalizations here, and probably upsetting a lot of electricians but this is just an estimate.

The last consideration is run time. The higher wattage generators will consume more gasoline, so if you do not need the largest model, then don’t get it. Check the run times on the manufacturers’ website.

How to hook them into your power grid:

Like everything else, there are a lot of ways to connect the generators power output to your house. If there is anything you take away from this, make it: DO NOT BACK-FEED POWER INTO THE GRID! You can kill the electrician trying to fix power for the whole area. What do I mean by back-feeding? When you have the main breaker still on and your generator is hooked into your house (by whatever method) you are most likely back-feeding power to the utility lines. Always turn off the main breaker (unless your setup is automatic or bypasses it).

• The first way to connect into your house is to just use the 240 volt dryer input. This is considered a quick and dirty way to get power back into your house. Using this method you can easily power the whole house, and also easily back-feed power so be careful. Also turn off any breakers that go to your main appliances like the oven so you don’t accidentally turn them on and kill your generator. To plug into the dryer outlet, you will need to purchase the correct cord end for your generator. The folks at your hardware store can assist with that. I didn’t hook it up like this because I don’t want a wire running from the window to the outside of my house.
• Another way to connect is to use a manual transfer switch. There are a bunch of different types out there, and they usually come with a wattage meter so you can see how hard your generator is working. Home Depot sells an easy kit with video, but it is a little expensive. I didn’t go this route because you are limited to only a few circuits and cannot hook up the whole house.
• The third way is to replace your electrical distribution panel/load center with a generator ready setup. This basically adds a 15 or 30 or 50 amp dual pole circuit breaker next to the 100 or 200 amp main house feed. It has a lever that makes you switch off the main feed to bring the generator online. I choose this route because I also needed more circuits for my house and this makes the cleanest installation. This doesn’t come with a wattage meter, so I purchased one of those separately and installed it under the panel.

The panel I used is from Gen Tran, Model: GTV1003D.

Now you can also just install a 30 amp dual pole circuit yourself and just make sure to shut off the main, but I wanted there to be no room for mistakes.

Replacing the distribution panel/load center involves removing the meter outside your house so power is shut-off. Do this very carefully and don’t say I didn’t warn you of the dangers. If you are unsure, HIRE AN ELECTRICIAN. The outside meter is basically a large fuse that connects the utility power to your homes power grid. To remove it, just clip off the lock that keeps it shut and open the panel. Make sure the main breaker in your house is off to avoid sparks. Pull the meter directly off without touching anything. The top contacts are HOT from the utility company, so DO NOT TOUCH THEM. There should be two of them coming in. This is so 240 volts will work properly, you need two 120 volt inputs. The neutral/ground is in the middle and it should be white.

On the load panel, take pictures before you do anything and just copy how the old one was setup. Make sure to label each of the hot wires (black ones) so you put them in the same place. Also write down the size breaker each wire has so you set it up in the same way. If you pulled the correct meter outside, there should be no voltage. Check this all with a voltage tester and multimeter before you get in there.

Make sure to balance out the circuits on the load center (read the documentation) so the load is shared on each input to the panel.

Other Info:

The generator I decided upon was the Briggs and Straton 8000 watt with 13,500 peak watts for starting up all those motors in my house.

I also installed an outlet on the outside of the house, where I can just wheel the generator outside and plug it in. This makes for a very clean installation. The plug I used is from Home Depot Pramac Power Inlet Box. Make sure to get the right plug for the size of generator you have. Get the correct size wire (10 gauge for 30 amps) for the run. Make it close to your load center is possible. Follow the directions for wiring the plug into you new load center if you choose this route.

The wattage meter I used has two meters up to 7500 watts each, RMK-15-I from Gen Tran.

As always, read the appropriate manuals before doing anything with the generator. Keep it maintained and keep good clean gasoline around the house. Get a lot of those 5 gallon gas containers.

For more information on home wiring, read this: Home Wiring

-Vinny

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