Backfeed to Subpanel

[nafterclifen]

Disclosure - I am asking this question for learning purposes only, not for installation. I am aware of the do's and don'ts of back feeding.

Is there any difference in the way that electricity is distributed and protected between panels if it's fed from a 240V generator via 20' 10awg copper on an L14-30P...

to a main breaker panel and then to a main lug, unbonded sub-panel
OR
to a main lug, unbonded sub-panel to a main breaker panel

Subpanel is connected to main panel with 10' of 2-2-2-4 AL.

 

[Hpozzuoli]

I love when these topics come up.

Think of your home as an island. To get electric there the power company sends it via wires. If you had no poco you would use a generator or solar power to get power to your island.

Backfeeding is a quick way to energize your home via an existing plug. Trouble is you need to be sure wire size, breaker size, and grounding/bonding is correct. I suppose before that you want to make sure you are not sending your electric from your island to someone else's. You need to shut the main.

A properly wired stand by generator is essentially backfeeding your home, sometimes thru a transfer panel or gentran switch.

***i suppose I need to state backfeeding is illegal and not advised.

 

[wyliesdiesels]

Yes there would be a difference.

Your second option has no way of preventing the backfeeding of the grid. Very dangerous for lineman!

First option allows u to use an interlock or transfer switch.

How would u do option 2 properly(and just shutting the main off isnt good enough!)

 

[nafterclifen]

Thank you for your concern but neither of you answered my question. Forget the backfeeding. Let me ask it a different way...

Does the source of power always have to be distributed in a bonded panel? If so, why?

 

[Speedy Petey]

Either way, you CANNOT backfeed a sub-panel from a generator, not unless that panel has it's own interlock or transfer, in which case only the circuits in that panel will be fed from the generator. It would become a generator panel.

 

[sberry]

Thank you for your concern but neither of you answered my question. Forget the backfeeding. Let me ask it a different way...

Does the source of power always have to be distributed in a bonded panel? If so, why?

No, not if its a 4 wire genset. Do not use a 3 wire 240 from a genset. There is no neutral.

 

[theoldwizard1]

...you cannot backfeed a sub-panel from a generator, not unless that panel has it's own interlock or transfer, in which case only the circuits in that panel will be fed from the generator. It would become a generator panel.

truth !