Advice on existing Sub-Panel feeder wires terminating to breaker vs. hot lugs?

MCINAZ said:

I recently purchased a rural property in Arizona. The property receives power from APS, the local electric utility. Power arrives from the utility meter, terminating to a 200AMP Main Service Panel in a Quonset Hut (think large garage). Inside the main panel is a 60AMP breaker that feeds a sub-panel responsible for powering the Water Well Pump and Control Box roughly 100' from the Main Service Panel. The Feeder Wire that connects the Sub Panel to the Main Service Panel Originates from this 60AMP breaker, but instead of terminating to Hot Lugs in the Sub Panel Box at the well, those two hot wires from the feeder connect directly into a second 60AMP breaker connected to the Sub Panel. I have never seen this before and could use some advice (photo attached of sub-panel config). I try to google search a sub-panel powered directly from a circuit breaker and get nothing, but likely not searching correctly. I have to assume this breaker (also given the "main off" label) is designed to be a cut off point for the sub-panel, but in my small brain I can't make sense of how it is working to power this panel, as the configuration is reverse of what I normally see, i.e. feeder hot wires connect to hot lugs, which powers the panel and all the circuits connected to it. The Well Pump and control box fed by the two tandem breakers on the panel seem to work fine, I just can't wrap my head around this set up. Is this better given the ability to cut off the sub-panel at the sub-panel and I am just overthinking it? Just never seen before and curious if I should rewire to Hot Lugs or leave "as is." Thanks...

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Electricity does not "flow" through wire like water flows through pipe. It "vibrates" back and forth changing direction 120 times per second, hence 60 hz. The 60 amp Main breaker in your sub is redundant and unnecessary but it harms nothing. Back-feeding through a breaker is perfectly acceptable, and done quite often. You can leave well enough alone.

As this sub panel is 100' from it's supply I suspect the wires were over-sized to combat voltage drop, and perhaps at the time of install the actual size of the well pump might have been unknown. The undersized ground and neutral from the feeder was likely rationalized on an economic basis, and justified that: were a 120 volt circuit ever be introduced, it would be a small load like a light and maybe a receptacle.

MCINAZ said:

I recently purchased a rural property in Arizona. The property receives power from APS, the local electric utility. Power arrives from the utility meter, terminating to a 200AMP Main Service Panel in a Quonset Hut (think large garage). Inside the main panel is a 60AMP breaker that feeds a sub-panel responsible for powering the Water Well Pump and Control Box roughly 100' from the Main Service Panel. The Feeder Wire that connects the Sub Panel to the Main Service Panel Originates from this 60AMP breaker, but instead of terminating to Hot Lugs in the Sub Panel Box at the well, those two hot wires from the feeder connect directly into a second 60AMP breaker connected to the Sub Panel. I have never seen this before and could use some advice (photo attached of sub-panel config). I try to google search a sub-panel powered directly from a circuit breaker and get nothing, but likely not searching correctly. I have to assume this breaker (also given the "main off" label) is designed to be a cut off point for the sub-panel, but in my small brain I can't make sense of how it is working to power this panel, as the configuration is reverse of what I normally see, i.e. feeder hot wires connect to hot lugs, which powers the panel and all the circuits connected to it. The Well Pump and control box fed by the two tandem breakers on the panel seem to work fine, I just can't wrap my head around this set up. Is this better given the ability to cut off the sub-panel at the sub-panel and I am just overthinking it? Just never seen before and curious if I should rewire to Hot Lugs or leave "as is." Thanks...

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You actually can get rid of the 60 amp breaker or keep it but the 60 amp breaker needs to have a tie down kit installed since power is coming into the breaker and not supplying a load. If it doesn’t have a tie down kit then it is not in compliance with the 2023 NEC.

MCINAZ said:

Inside the main panel is a 60AMP breaker that feeds a sub-panel responsible for powering the Water Well Pump and Control Box roughly 100' from the Main Service Panel.

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There is nothing inherently wrong with this part of the layout.

There is another option that you may want to consider. Those supply conductors could be connected as underground service conductors supplied from the load terminals on the load side of the meter socket. The US National Electric Code specifically allows one of the 6 maximum Service Disconnects to be located remotely from the other disconnects, instead of grouped in one location, to supply power to a water pump that would be used for first aid firefighting. That is done by running a set of service entry conductors from the meter socket load terminals or Service Entry Conductors, prior to the Service Disconnect Enclosure, to the Well Pump controller.

Although not required BEST PRACTICE would be to house all of the equipment needed for continued water supply in a well house or vault rather than in one of the structures the pump would be used for firefighting in that building. The advantage to the use of a well vault is that no heating is required if it is installed below frost depth. If a well house or vault is not practicable then consider installing the pressure tanks in the smallest building that has a space which will remain above freezing by at least 10° Fahrenheit; 12° Celsius. This presumes that the smallest building will be the one that will cause the least hardship if it is destroyed by fire.

MCINAZ said:

The Feeder Wire that connects the Sub Panel to the Main Service Panel Originates from this 60AMP breaker, but instead of terminating to Hot Lugs in the Sub Panel Box at the well, those two hot wires from the feeder connect directly into a second 60AMP breaker connected to the Sub Panel

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That is very commonly done and there is no US National Electric Code (NEC) violation in doing so. As someone else already pointed out the NEC does require a breaker tie down when a breaker is supplied through what would normally be its load terminals. That is to prevent the accidental removal of the breaker from the busbars while it's busbar terminal connectors are still energized. There is usually a label included with the tie down kit that warns that the breaker must be open before it is removed from the panel's busbars.

MCINAZ said:

I have to assume this breaker (also given the "main off" label) is designed to be a cut off point for the sub-panel,

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If the well and control panel are in or on a structure of some kind the 60 ampere breaker would also be the building disconnecting means which is required by the NEC on a feeder of this size.

MCINAZ said:

The Well Pump and control box fed by the two tandem breakers on the panel seem to work fine,

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That twisted wire through the handles is not acceptable as a handle tie and handle tied breakers are not acceptable for the protection of 240 volt circuits. That breaker should be replaced by a 2 pole breaker because it is a 240 volt circuit. You could still use the 2 tandem breakers for 120 volt circuits but not for 240 volt.

MCINAZ said:

Is this better given the ability to cut off the sub-panel at the sub-panel and I am just overthinking it?

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It is a good idea to have some sort of main disconnect at a remote panel to reduce the temptation to avoid the 100 foot walk and work the panel hot.

MCINAZ said:

should rewire to Hot Lugs or leave "as is.

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I think that you would be better off to add a breaker tie down and let it eat. It is customary, although certainly not required by the NEC, to place such a breaker on the two breaker connections furthest to the left. Mark the breaker itself with the words "Main Disconnect" so that it is still labeled when the dead front is removed.