Five Letters Re: Tips on Selecting and Operating a Generator


Re: Gary D.’s piece on generator use. Good article; I’ve learned a few additional things over the years about generator usage which your readers may find helpful.

Power cords – usually, they’re undersized for the load. There are different American Wire Gauge (AWG) specifications for current carrying capacity:

16 gauge – 12 amp maximum for 25 ft, 3.4 amps for 100 ft.
14 gauge – 16 amp max at 25 ft, 5 amps at 100 ft..
12 gauge – 20 amps at 25 ft, 7 amps at 100 ft.
10 gauge – 30 amps at 25 ft, 10 amps at 100 ft.
 8 gauge  – 40 amps at 25 ft, 14 amps at 100 ft.
 6 gauge  – 65 amps at 25 ft, 22 amps at 100 ft.

The smaller the gauge number the larger the actual diameter of the wire and the greater its current carrying capacity.

Large AWG weather resistant copper-conductor cable (8 gauge, for example) will be expensive. 100 feet of 8-3 SO (three 8 gauge conductors, weather and oil resistant sheath) will cost between $200 and $250, but it will carry a lot more current safely than “home center” extension cords.

Twist lock connectors, especially female connectors, are expensive. Use them anyway – they won’t partially disconnect due to vibration or being bumped.

Use high capacity cable as a primary feed, and build a multi-outlet box on a short, lower capacity cable to connect to it. Mine is a 4-gang steel box with duplex receptacles on a 15 ft 10-3 cable with a male twist lock connector to connect to the 8-3 cable.

Do put a Ground Fault Circuit Interrupter (GFCI) receptacle into your multi-outlet box, and wire it to provide protection for the outlets. My 4 gang box has the GFCI, which also protects 2 of the remaining 3 receptacles. One receptacle is not GFCI-protected for those instances where there may be equipment with internal circuitry that frequently trips the GFCI. That one duplex receptacle is red to identify it as non-GFCI protected, purchased in that color from an electrical supplier.

An earth anchor, designed to anchor garden sheds to the ground, permanently installed, provides a place to chain and padlock your generator. Your local utility can sell you one of the big ones they use to brace power poles if you need a bigger one. Dig a shallow hole with a post hole digger to install it, so when installed the loop is just below ground level. Put a lawn irrigation system valve box around it, flush with the ground. Your lawnmower will thank you.

Use the earth anchor as the ground connector for your generator. An inexpensive auto jumper cable with large clamps can be used to connect the generator frame to the anchor if there’s no ground lug provided on the generator. Remove the paint from the generator frame where you connect the cable clamp to get a good connection.

If you’re building, or doing major remodeling, put in one electrical circuit that feeds one outlet in each room. If possible, put each room’s ceiling fans on this circuit, too.  If you have, or are installing a transfer switch, put this circuit on it. This allows easy distribution of generator power to each room.

It’s handy to have one or two convenient outdoor receptacles on the transfer switch in case you need power outside.

Put in another dedicated circuit with 2×3 (duplex receptacle-sized) outlet boxes in the ceiling in strategic places (hallways, kitchen, bathrooms, etc.) Control this circuit with either the breaker in the transfer switch box and/or 3-way (or 4-way) wall switches in case you need complete dark. Install Pass & Seymour or Cooper Wiring LED night lights in those boxes; the night lights draw almost no power, and provide just enough light for navigating around the house and for target identification, and are safer than candles.

Even quiet generators make noise. Put sound absorbing foam on two pieces of plywood, 4 ft wide and long enough to extend past your generator a foot or so at each end. attach the long side of each to a 2X4 with hinges so they can be placed as an A frame over the generator. A 4ft x 4ft piece covered on one side with sound absorbent can be placed vertically several feet in front and behind the A frame. I attached pieces of 1/2″ EMT (Electrical Metallic Tubing) to mine, to act as stakes. Leave room for ventilation, and if more air flow is needed for cooling, plug a fan into the generator, set to blow air through the A frame cover.

If you’re using a generator to power your well pump, replace the small pressure tank the builder put in (probably about a 6 gallon draw down) with one or two larger tanks. I put two 46-gallon draw down tanks in parallel; when water is needed, turn off all circuits in the transfer switch except the well pump, then turn on the well pump. It will run for however long it takes to fill both tanks, and you’ll have 92 gallons to use before needing to turn the pump on again. In day-to-day use the pump won’t start/stop as frequently, making the pump motor last a lot longer.

Talk to your well driller or plumber who understand wells about a second, smaller well pump. It is possible to install a second pump with a check valve between it and the delivery pipe to the house. In day-to-day use the 1 HP or 3/4 HP pump supplies routine needs, in a SHTF situation the 1/8 HP – 1/4 HP  pump draws a lot less current, allowing a smaller generator. A smaller pump will need to be installed higher in the well and electrically on its own circuit, and it will deliver less volume, usually at a lower pressure, but 2 GPM at 25-30 PSI beats 0 GPM at 0 PSI. And, “two is one, one is none.” – Nosmo King

I really enjoy reading the articles contained on your blog and wanted to mention a few items related to the subject above. As a person that lives on generator power 24/7 I wanted to contribute to the conversation.

Gary wrote a wonderful article and I wanted to add a few things. The first thing is that not all generators are rated for continuous use and most of the “off the shelf chinese models” are only rated occasional and should only be used in light duty situations. The small “suitcase” style generators definitely have their place and the quiet Yamaha and Honda powered ones are the cream of the crop but I wouldn’t want to depend on one for the long term.

If you are mechanically inclined, don’t rule out purchasing a used “take out” generator from an RV, some of these can be had for a real bargain and can be found in junkyards, on Craigslist as well as other places on the web. In addition to having multiple fuel options available, these units are 4KW and above and can be easily run from a gas can, propane tank or other external fuel source. The smaller units (4KW) can be easily mounted to a garden wagon for portability, the downside being having to have an electrician wire up a junction box.

When you purchase or even if you presently own a portable generator take a good hard look at the connections on the panel. Have adapter cords made for any twist lock or RV style outlets so that you can fully utilize the power from the equipment, RV style adapter cords and plugs can be purchased from most camping stores or even Wal-Mart.

Lastly and probably most important, make sure the generator is grounded whenever it is in operation. – B.I.

That was a great article on generators by Gary D.

As he points out, noise is bad, but it can be mitigated. There is a good method described over at the Alpha-Rubicon site. Best Regards, – Don in Oregon

I have no argument that accidentally “backfeeding” power from a generator (even a small one) through a house outlet-to the electrical box, and to the power grids can hurt or kill a utility worker, but it will also burn out, the portable generator in question within 10 seconds. The gas engine will be fine but the generator half of the machine becomes useless. This fact is not often reported. – Bob M.

With two recent posts on operating a generator and alternative power systems, both of which mention transfer switches, I thought it might be valuable to again mention a device that might be of interest to your readers. The Generlink device is an alternative to a transfer switch at lesser cost and more versatility in operation.  Regards, – Keith  

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