Good morning. Came across a panel that is being used in conjunction with a generator. The panel is connected to the main service panel by means of a 40 amp breaker. The panel itself has me scratching my head as there are no neutrals or grounds for the individual circuits. Not exactly sure how these panels are supposed to be wired when used in this capacity. Any help with this would be much appreciated. I’ve attached multiple photos that I have of both panels
The breakers on the subpanel are basically extensions from the previous panel. The service panel has several old breakers that are no longer wired, and they extended those conductors to the new breakers. So the neutrals and grounds are still in the service panel.
That way they can shut off the main service disconnect, and turn on the generator back- fed breaker.
However, it should have an interlock switch on the subpanel, and if that double 20amp is for back- feeding the generator, it is turned on right now, which will be energizing that plug. (Hence one reason for the interlock)
Is that what the double is for? Typically a generator would have a 30 amp
1 Like
There is much debate as to whether or not this is code compliant. As Daniel stated you need an interlock kit on the backfed circuit breaker coming from the generator. Take a look here for a lengthy discussion.
3 Likes
Thank you guys for replying and helping me make sense of this. The double is listed for the well pump.
Thx Robert.
What is the code for running feeders and circuits in the same conduit?
And would you say anything about the circuits likely needing a neutral if they should be afci?
(The service panel didn’t have any anyways)
1 Like
They can both be in the same raceway so that is okay. As long as the raceway is 24" or less you won’t have any derating issues to deal with. Derating may require larger than normal conductors.
You’re correct about the AFCI protection, if required there would need to be AFCI circuit breakers in the generator panel and that would require a neutral.
3 Likes
I’m assuming there’s a transfer switch between the main and sub (40 in main is labeled as transfer switch). The sub would be the only circuits fed by the generator. Wouldn’t the neutral have to be switched as well in this case?
1 Like
I believe you dont need a transfer switch. It can be fed directly to the panel with an interlock. (which he is missing)
It looks like the sub is fed currently with the top right breaker at the main. When power is out, it would be fed by the conductors coming in at the bottom left of the main with a generator. But it isnt set up correctly to have an interlock switch like that.
1 Like
I just figured since the top right 40 in the main is labeled “transfer switch,” that one may be installed. Maybe the OP can clarify.
2 Likes
I didn’t see a transfer switch. Am i under the correct assumption that if a auto transfer switch were present the panel would no longer require an interlocking switch
Correct, but that is typically done with a generator that will power the entire home. It is then placed between the meter and the panel to prevent current from backfeeding into the grid. (dangerous for line workers) Same reason for the interlock, but its usually just done manually when just a few circuits are involved, and a generator that has to be started manually.
1 Like
Thanks for clarifying, unfortunately we don’t run into too many generators up this way so I was confused by what I was seeing. Great to learn all this
There is some information missing in this installation. The 2-pole 40 feeds the sub-panel so where are the conductors from the generator?
2 Likes
If the labeling in the pics is somewhat correct, the genset is not hooked up or backfeeds the main panel and then the whole subpanel is just that.
It looks like the breaker labeled ‘transfer’ feeds the subpanel but then there are also feeders coming from the bottom left of the main panel going into the same conduit it looks like?
It’s a mystery to me how this is set up. Maybe some more photos could shed some light on it.
3 Likes
I’m thinking there is a transfer switch somewhere. It would be odd to have the 40 amp breaker labeled “transfer switch” (but of course not impossible) unless someone knew what they were doing. I don’t really see any other way that the generator could be feeding anything. And if you look at the items on the sub-panel list, they are the most common items you would most likely want to keep energized during a power outage.
My question though is, what happens when the neutrals for the branch circuits are not connected to the generator? What if the power outage includes the service neutral being out? Then the only way to complete the circuit in the OP’s situation is through the home’s GEC, correct?" Would that even work?
Improper identification of the conductors, grounded conductors smaller then 4 AWG need to be white, or gray along their entire length. SQ D Homeline breakers installed in competitive equipment is always wrong, they are not UL classified to be used in competitive makes, only 1" wide breaker that is is Eaton CL, which is not the same as Eaton BR.