3 way switches for transfer switch

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Old 12-09-14, 09:55 AM
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3 way switches for transfer switch

Hi All, just ran across this one ,person had a 4 gang switch box nippled to the side of his panel , 4 -3 way switches connected to an extension cord to connect to a portable generator,loads are supplied when the switches are in the emergency position to supply selected loads,normal switch position loads are supplied from service.
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Old 12-09-14, 11:27 AM
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Geeze Louise! But he gets fairy points for creativity.

On the other hand maybe DPDT? Hmm trying to work the diagram in my head hmm?
 
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Old 12-10-14, 12:10 AM
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Using a three way switch...... the common goes to the load.
4) three way switches.
 
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Old 12-10-14, 05:48 AM
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Using a three way switch...... the common goes to the load.
4) three way switches.
If the generator backed up 4 circuits, what was the amperage of each of those circuits? How did the dude get 4 circuits of the proper amperage from the generator? Just food for thought.
 
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Old 12-10-14, 06:03 AM
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I guess 1 load at a time, boiler for awhile,freezer and fridge for awhile,then flat panel etc. basically only 1 circuit at a time.
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Old 12-10-14, 06:28 AM
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This is almost the same thing as a "transfer box" containing perhaps from six to twenty small switches for that many selected branch circuits respectively. Such a transfer box is typically installed next to a breaker panel. A single connection, usually a male receptacle, is on the transfer box to connect to the generator using a standard generator cord.

A transfer box has overcurrent protection for each branch circuit it serves. Or its single connection facility to the generator is 20 amps or less.

For the homemade box described here, each branch circuit of 15 or 20 amps must terminate in its own hanging cord (12 gauge for a 20 amp circuit) with 15 or 20 amp. respectively plug (or male receptacle in a neighboring box), or they can share* one or more hanging cords with 15 or 20 amp plugs, 15 amp if any of the circuits sharing the cord are 15 amp circuits. The hanging cords are then plugged into the 15 or 20 amp receptacles of the generator using extension cords if needed.

Don't forget that the plug is supposed to imply the maximum amperage of the circuit or subcircuit or appliance or other load. A 20 amp receptacle should be powered by a branch circuit protected to 20 amps so anything connected with a 20 amp plug will get no more than 20 amps total. However individual appliances or other loads that may require more than X amps should not be wired to an X amp plug.

A 3 way switch is a single pole double throw switch. A double pole double throw switch could be used in a transfer box to control a 240 volt circuit in 120 volt regions. A DPDT switch may also be found in 3 way applications but sometimes does not work out well where depending on the positions of other switches, it flips one light on at the same time if flips another light off. A 4 way switch is not an SPDT switch or a DPDT switch.
.

* One 20 amp branch circuit to receive generator power via the makeshift box or a real transfer box may not be connected to two 15 amp transfer box circuits or two 15 amp hanging cords to obtain 20 amps.
 

Last edited by AllanJ; 12-10-14 at 06:59 AM.
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Old 12-10-14, 07:37 AM
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I haven't seen it done to that extent, but I have seen a single 3-way switch approved by the AHJ for emergency power on a furnace. It really shouldn't be approved as the 3-way switch is not listed for the purpose. I do like it better than a suicide cord or a backfeed, but it's one of those situations where what you don't know will hurt you.
 
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