Breaker feeding outbuilding

I inspected a home today that had a double 40 amp breaker (tied), shown on the upper left of the panel, feeding a 150 amp main breaker panel in the pole barn.
Is this appropriate??

I see no problem with it as the 40AMP is your feeder and will trip if an overload is obtained. Just make sure to tell your clients that it is only 40AMP.

The #8 wire from the 40 amp is feeding the sub panel in the garage. That subpanel usually wont have its own main breaker unless they are using that 150 amp breaker as a power turn off control at the sub panel location for whatever reason. There is no way that sub panel can be protected for 150 amps. The 40 amp breaker in the distribution panel will trip if the subpanel breakers try and suck too much juice. I think they just threw the 150 amp leftover breaker in there as a way to shut power off to the sub panel rather than shut it off at the main panel.

I see this all the time here. They use a panel big enough for the amount of circuits. It just happens to be a 100 or 150 so they install the main breaker as a sub Panel disconnect but the 40AMP is the actual disconnect from the main panel.

The 150 is serving as the required disconnect.

As long as the load is less than 40 amps this is fine.

As Jim stated, since this outbuilding is a separate structure a disconnecting means is required. Since it’s often cheaper to buy a panel with a main CB this can serve as the disconnecting means even if it’s larger than the OCPD ahead of the feeder.

As long as the load in the barn isnt going over 40amps its ok. The main breaker is needed in the outbuilding as per NEC.

Just of note I see a double tap on the neutral buss. Also, it doesn’t appear to stand out from where Im at, but since this panel has thin breakers make sure any shared neutral circuits are on different phases. Common issue I see sometimes being a red and a black will end up on the same phase just because of the phase sequence pattern. Ie, your breakers here are A,A,B,B,A,A rather than A,B,A,B.

It has to have a disconnect at the structure?

I recently ran two circuits to my detached garage. One for lights, one for receptacles. The only disconnects are the breakers inside the house. My understanding was since I didn’t install a panel in the garage, I didn’t need a disconnect out there?

A single circuit still requires a disconnect. It can be as simple as a toggle switch.

Unless what you ran was an MWBC there is a code violation. You are allowed one source of power to the shed unless the system characteristics are different.

As Jim stated this installation would have two violations, one, the lack of a disconnecting means and two having two separate circuits run to the separate structure. In general you can only have one feed run to a separate structure. If you need two circuits it can be 1-3 wire MWBC but not 2-2 wire circuits.

uh oh… guess I better change it.

The only feasible way to do it is to connect the lite circuit to the receptacles, then do away with the circuit feeding the lights.

I can then just put a disconnect before the first receptacle.

If you have only one circuit then a simple single pole switch can serve as the disconnect. It should be installed where the branch circuit conductors enter the building.

If you have a MWBC use a double pole switch or an AC pullout disconnect.

I don’t have a mwbc. I have (2) 12 gauge wires ran on separate circuits. It would be easy to tie them together at the first receptacle (attached to the outside of the building), and put a weatherproof switch before that receptacle.

I was avoiding tying the two together because the power tools will cause the fluorescent lights to flicker. I suppose I should have installed a sub panel in the garage, but I can’t now without running a mwbc.