Main Lug 6 Breaker 3 Phase (6 hand operations)

Joethemechanic

Joethemechanic

Senior Member
Location
Hazleton Pa
Occupation
Electro-Mechanical Technician. Industrial machinery
Something like this

Screenshot 2025-10-05 173132.png

Can the sum total amperage of the breakers exceed the amperage of the service?

Using this panel for example, could you install six 25 amp 3 phase breakers for a total of 150 amps? And if so, what are the limitations and can the sum of the amperage exceed the rating of the service conductors also?
 
hillbilly1 said:
Can’t use that panel as service equipment anymore. Has to be separate enclosures, or barriers.
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OK, so suppose I'm using the right 12 space main lug panel with the main lugs covered?

I wasn't planning on using that particular panel anyway, It was just the first one that was close to the description, not to mention the rating is too low
 
Joethemechanic said:
OK, so suppose I'm using the right 12 space main lug panel with the main lugs covered?
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Starting with the 2020 code you can no longer have more than one service disconnect in a common enclosure. Each service disconnect must be in its own compartment, and UL 67 has defined a compartment as an enclosure that complies with UL 50, the standard for junction boxes.
 
don_resqcapt19 said:
Starting with the 2020 code you can no longer have more than one service disconnect in a common enclosure. Each service disconnect must be in its own compartment, and UL 67 has defined a compartment as an enclosure that complies with UL 50, the standard for junction boxes.
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We still are using 2017
 
Joethemechanic said:
We still are using 2017
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Concept is still ok with 2017. The particular panel you pictured however never would have been allowed per it's listing. All QO load centers that I know of are only suitable for use as service equipment if they have a main breaker installed.

I have used the six main rule in the past with certain I line panels. Not all of those are listed to do this with either though.

I don't know if they have changed any of those listings since the 2020 rule came along though. Haven't encountered a situation where it was a consideration.

2020 and later you can still use the panel you pictured as the main panel of a building with just the six disconnects if the supply is from a feeder and not service conductors though.
 
Joethemechanic said:
So, if I'm reading this right, the service conductors, meter socket, and panel have to meet or exceed my load calc numbers?
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Or to rephrase that, the service conductors, meter socket, and panel have to meet or exceed my load calc numbers and not the sum total amperage of the six breakers?
 
Joethemechanic said:
If the load calc numbers come out higher than my historical maximum demand (Over 15 minutes) can I use the lower actual demand numbers?
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ActionDave said:
That would be practical, sensible, rational so of course it's not allowed.
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Hmmm, I would say the demand numbers would be fine. Here is what the relevant sections say:

230.90 Exception No. 3: Two to six circuit breakers or sets of fuses shall be permitted as the overcurrent device to provide the overload protection. The sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors.

220.87 Determining Existing Loads. The calculation of a feeder or service load for existing installations shall be permitted to use actual maximum demand to determine the existing load under all of the following conditions:

I don't think anything in 220 has to give us permission to use 220.87, if it did, I dont think we could ever use it.
 
The only large load that runs pretty regular is a 15 HP air compressor. I have some big welders, and machine tools but they are all 1950's and 60's stuff so it's not like I'm doing any production work and have a man on every machine. This is a repair shop, the stuff can go days or weeks and never get used, and even when it is used it's rarely at full power. I don't think I've been over 30 KVA (15 minute) ever. Even when there were all the trucks here with block heaters plugged in during the winter that was only a 27 KVA load and being it was on a timer they only were on for a couple hours before the drivers came in
 
Deltaforce said:
RES connected
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This is the Coal Region. Around these parts we think anyone associated with renewable energy is a Communist that is only here to corrupt the minds of our women and children.

Our idea of "renewables" is burning old tires to power crypto mining.

But as usual the greenies are against us because they want to corrupt our women, and harvest adrenochrome from our children

A bitcoin mine located at a waste coal power plant in Pennsylvania wants to add a new fuel to its power generation mix: scrap tires.

Stronghold Digital Mining describes itself as an “environmentally beneficial” bitcoin miner. But during a virtual press conference on Monday, Russell Zerbo, an advocate at Clean Air Council, said the facility, Panther Creek, had received at least seven air quality violations since it was acquired by the cryptocurrency mining company in 2021.

The press conference brought together representatives of local and national environmental organizations, including Earthjustice and PennFuture, along with residents of Carbon County—where the plant is located—to ask the Pennsylvania Department of Environmental Protection to reject Stronghold’s permit application for this new fuel source.


Tires are a significant waste problem: The United States generates some 300 million scrap tires every year. According to the EPA, burning scrap tires is better than dumping them in a landfill, but not as beneficial as finding ways to reuse or recycle them. In a landfill, the flammable materials that tires are made of can pose a risk of uncontrolled tire fires. Abandoned tires can also become breeding grounds for disease vectors like mosquitoes.
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Joethemechanic said:
The only large load that runs pretty regular is a 15 HP air compressor. I have some big welders, and machine tools but they are all 1950's and 60's stuff so it's not like I'm doing any production work and have a man on every machine. This is a repair shop, the stuff can go days or weeks and never get used, and even when it is used it's rarely at full power. I don't think I've been over 30 KVA (15 minute) ever. Even when there were all the trucks here with block heaters plugged in during the winter that was only a 27 KVA load and being it was on a timer they only were on for a couple hours before the drivers came in
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OK. what md data from your utility say?
 
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