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Old 08-20-2011, 08:16 AM   #1
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wire size vs breaker size

I have an existing 240v circuit with 8-3 cu wire (not in use). It requires a 50a breaker, but I would like to use this for a 30a generator, that backfeeds back into my 200a panel that is equiped with a 30a generator throw switch.....question is, due to size of wire (8/3), can I install a 30a outdoor gfci for the backfeed, or do I need to install new 10-3 wire? Thanks


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Old 08-20-2011, 08:41 AM   #2
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Yes you can use an over sized wire wire for a smaller load. However I do not think you can back feed a GFCI.


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Old 08-20-2011, 08:43 AM   #3
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You cannot back feed a regular receptacle from a generator. You would need a suicide cord to do so. NOT GOOD!!!!!

Get a proper inlet.
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Old 08-20-2011, 09:41 AM   #4
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You can replace the receptacle at the end of that 8-3 gauge line with a male receptacle (inlet), also replace the breaker with a non-GFCI double breaker. You must put an interlock system on the panel so both the breaker for that 8-3 circuit and the main breaker cannot be on at the same time.

In localities where cam-lever panel interlocks are not permitted, the transfer switch must be in the feed line for the main panel. This can require coordination with the power company to pull the meter when you are installing this tranfer switch.

If all of the circuits eligible to get generator power are in a subpanel, this 8-3 line can be rewired to a transfer switch in the feed from the main panel to the subpanel.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.

Last edited by AllanJ; 08-20-2011 at 09:45 AM.
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