[tkrussell]

It sounds like a furnace 3-way switch connected to a generator via a power inlet receptacle works just like a transfer switch, but with no circuit breaker. Is this the only difference?

Correct.

Does it then follow that connecting a refrigerator or other appliance directly to a generator with an extension cord would present the same problem?

Correct.

Lastly, is there any possible scenario where a 3-way switch could backfeed?

None.

Be aware that I am not in any way a proponent of nor condoning 3 way switches to be used as transfer switches.

[labman]

You might look at setting an outlet and adding a cord to you furnace. Note, The plate on my furnace lists 12 amps max. All the components would need to be rated for at least 15 amps. I have a fused shut off at my furnace. I could instal the plug and outlet before it, retaining the fuse protection. Then I could run my furnace off an extension cord.

Unfortunately, there have been some reports of furnaces refusing to run on perhaps poorly regulated generator current. Maybe I will even rig mine up as a test before investing in a transfer set up. The search feature works well here, try something like generator + furnace.

[jorgef]

You might look at setting an outlet and adding a cord to you furnace.

RE: Comparing furnace plug/outlet to 3-way switch.

A plug/outlet configuration would disconnect both the hot and the netural when the plug is alternated between generator and branch power. A 3-way switch would disconnect only the hot. So, is a common neutral with a 3-way switch at all problematic? I have read these claims:

a) Linesmen can be jolted by backfeed through common neutrals.

b) The neutral must be switched to prevent current from flowing on the equipment grounding conductor, e.g. a failed common neutral could fry the generator.

[tkrussell]

I never heard of a neutral causing a backfeed, since a neutral is grounded, both at the service and at the utility pole.

Most transfer switches whether manual or automatic do not switch, or open the neutral, and the genset neutral is tied directly to the system neutral, and, as I said, grounded. These are called Non-Separately Derived Systems.

Therefore, the neutral is at zero potential, and a lineman will not get hurt working the neutral. When they do work on the hot lines, they intentionally ground those hot wires to the neutral and/or ground line to be sure the hots are brought down to zero potential.

Can you provide some reference regarding:

a) Linesmen can be jolted by backfeed through common neutrals.

b) The neutral must be switched

[jorgef]

Can you provide some reference regarding:

a) Linesmen can be jolted by backfeed through common neutrals.

b) The neutral must be switched

The above are claims made by users in other electrical forums, and they may be entirely incorrect. In seeking the opinions of others, such as those in this forum, I was hoping to discern fact from fiction. I believe you've done that for me and I appreciate your responses.

[onamission1]

Hmm interesting

[Stratmando]

Onamission, this is an old post. Not sure the Interlockkits were available then, They are available now, and Personally I think it is the Best/safest/most efficient way for Transfer.
Instead a small panel of Selected circuits, you can use anything on your Panel so long as it doesn't exceed the Generators Capacity.
You need a Power inlet box, and the Interlockkit. I only allows the Main Breaker to be on OR the Generator Breaker, No Backfeeding. Most Cost Effective:
http://www.interlockkit.com/
EDIT
I just looked back and the Interlockkit was mentioned, Although it is just metal Plates and stickers, It prevents backfeeding, it is much cheaper than the 8,10, 12 or whatever circuit transfer panel. You will pay more for the transfer panel and only a few select circuits can be used.

[ohb0b]

Actually, cheap transfer switches use "3-way" switches to individually switch branch circuits instead of transferring the entire service. These switches have individual fuses installed which take the place of the circuit breakers in your panel.

http://www.amazon.com/gp/product/ima...&n=228013&s=hi