Generator hookup

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  #1  
Old 01-28-07, 07:03 PM
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Question Generator hookup

I plan to temporarily activate my main breaker box with a small 3.5kw generator. I have about 10 unused breaker locations. I plan to run a 4 prong 240 line to the breaker box with a 20 amp 240 double breaker. I wish to run a well pump 1/2 hp 240v 5 amp rated pump motor, which is now on a 20 amp 240v breaker. After I have obtained my water I plan to trip the pump off. Then I will run my furnace 4.0 amp 120 vac motor. The main breaker will be off line. I plan to use 12/4 conductor wire about 20 feet. Is this plausible?
 
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Old 01-28-07, 07:11 PM
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The generator power is a bit low. Your plan is wrong.
Use aTransfer panel for the generator power. This adds no more breaker space to the panel. DO NOT BACKFEED into the panel.

The transfer switch is a 3-position switch. This will not allow a backfeed.
And insures at no time will there be two available sources.
 
  #3  
Old 01-28-07, 07:58 PM
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"Is this plausible?"

What you plan is unsafe, dangerous to utility workers and highly illegal!
(I wish the vB codes were working because this would be in BOLD)

PLEASE do as Lee said and install a proper transfer switch or transfer panel.
It is cheap insurance that everyone remains safe.
 
  #4  
Old 01-29-07, 04:36 AM
Join Date: Jul 2006
Location: Southeast MI
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Originally Posted by rocketscientist View Post
I plan to temporarily activate my main breaker box with a small 3.5kw generator. I have about 10 unused breaker locations. I plan to run a 4 prong 240 line to the breaker box with a 20 amp 240 double breaker. I wish to run a well pump 1/2 hp 240v 5 amp rated pump motor, which is now on a 20 amp 240v breaker. After I have obtained my water I plan to trip the pump off. Then I will run my furnace 4.0 amp 120 vac motor. The main breaker will be off line. I plan to use 12/4 conductor wire about 20 feet. Is this plausible?
Rocket-

Yes, it is plausible, but please listen speedy & lectriclee. If you don't want to go thru the expense of a separate sub-panel for the protected loads, or you don't have the space where the main panel is, then you still do have an option.

Depending on the model of main panel you have you may be able to install the safety interlock right in the main panel. This interlock serves as a safety net against the aforementioned back-feeding hazard by meeting the four criteria spelled out in the NEC:

1) Both breakers must be able to be off at the same time (center-off)
2) Both breakers must NEVER be on at the same time
3) Both breakers must be affixed to the main panel (permanently fastened)
4) This protection must remain in place with the dead-man cover (panel cover) removed.

I have seen an interlock kit for the Siemens 100A panel that uses a sliding mechanism between the main breaker and the Generator breaker. The thing here is that your main breaker now takes up the two top slots on one side, while the generator breaker takes up the two top slots directly across from it.
The lock-out slide goes over both breakers' handles and doesn't interfere with normal operation. The mounting bracket goes around the two breakers and keeps them in place to meet the permanent-mounting requirement.

Its operation is pretty straighforward: when the power fails, flipping the generator breaker on will cause the main breaker to trip FIRST, BEFORE the generator breaker closes. This is the "center-off" function. Since the slide mechanism goes under the lid cover, its function remains in place whenever the cover is removed.

NOT doing this will make your safety (not to mention that of the line workers) dependent on your remembering to open the main breaker first, which is both Dangerous and Illegal.

Square-D makes a lockout kit for both their Homeline and QO panels up to 225A, and does not require you to move the main breaker out of the center position onto one of the rows like the Siemens kit requires. Goes for about $40 at Lowe's & Home Depot.
 
  #5  
Old 01-29-07, 09:00 AM
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I would definitely agree with Circuit Breaker and say do the interlock kit. If you have the extra spaces and want a simple setup, that is the way to do it.
 
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