Embedded Files
Breaker Compatibility
Design
COMPATIBILITY SHORT LIST
COMPATIBILITY SHORT LIST
The following short list will help you make breaker make/model callout choices regarding breaker compatibility. Over the years, many of the now discontinued makes were purchased by a few of the more common major brands which has resulted in some cross compatibility with older load center makes/models:
EATON
Eaton (BR type)
Bryant
Thomas & Betts
Westinghouse
Challenger (Type C)
GTE Sylvania (Type C)
SIEMENS
Siemens
I-T-E
Gould
Murray
Milbank
Arrow-Hart
General Switch & American Switch
CUTLER-HAMMER
Cutler Hammer original load centers/breakers
Eaton type CH load centers/breakers
NO OPEN COMPATIBLITY
Cutler Hammer (& Eaton CH type)
Square D HOM
Square D QO
Leviton
Federal Pacific/Stab-Lok
Zinsco/Sylvania
Bulldog/Pushmatic
EATON
EATON
BASELINE DT
BASELINE DT
As noted above, Eaton owns both Westinghouse and Cutler-Hammer. This can be tricky when distinguishing between BR-type breakers and load centers and CH-type breakers and Load Centers.
The "EATON" callout in the Basline DT refers to Eaton BR (black handle).
The "Cutler-Hammer" callout in the Basline DT refers to both original Cutler Hammer (CH) load centers and newer Eaton CH-type load centers (tan handle).
BREAKERS
BREAKERS
By far, the easiest way to identify a BR type panel vs a CH type panel is by the breakers:
BR breakers are all black.
Will have the prefix "BR" on the model number.
Note that BR breakers don't always have the signature "EATON" logo. Looking for the "Type: BR####" model number will be the key to this.
THINNING BREAKERS
THINNING BREAKERS
Eaton regularly manufactures the following types of standard circuit breakers:
Single pole breaker
2 pole breaker
Duplex breaker
Triplex breaker
Quadruplex breaker
PANEL LABELING
PANEL LABELING
Notice the label says "Loadcenter Type: BR." This tells us that this would be called out as EATON in the design tool.
CROSS COMPATIBLITY EXAMPLES
CROSS COMPATIBLITY EXAMPLES
Example 1:
In the photo to the right, just below the breaker handle, the branding reads "Cutler-Hammer." This can be deceptive because Eaton also owns Cutler-Hammer which is the more common term used to refer to the tan handled Type CH breakers manufactured under both the name Eaton and Cutler-Hammer:
The callout should be EATON when "Type BR" is listed as highlighted in the photo to the right.
Example 2:
This photo depicts an older, refurbished Bryant type breaker. the "BR" prefix on the model number owes it's marker to this brand. Eaton acquired Bryant many years ago and though the original Bryant breakers and panels were discontinued, Eaton's modern breakers are made in the same "BR" style and are suitable as replacement breakers for Bryant Load Centers.
Bryant is identifiable by their square appearance, similar in shape to the modern Eaton BR type breakers, however, this brand used color coding to denote current rating along with the imprinted value on the breaker handle.
The callout should be EATON.
Example 3:
This photo shows a Thomas & Betts breaker. This is another brand that has been discontinued, but Eaton BR is a suitable and listed replacement for this make.
Thomas & Betts is best Identified looking for the "T&B" label and a "Type TB" part number prefix.
The callout should be EATON.
Example 4:
This is an original Westinghouse Breaker. This is another brand that was acquired by Eaton.
Westinghouse is best Identified looking for the unique "W" logo as highlighted to the right.
It may be easier to look at the panel labeling rather than the breakers themselves.
The callout should be EATON.
Example 5:
This is an original Challenger Breaker. This is another brand that was also acquired by Eaton many years back.
Most challenger breakers have clear labeling reading "challenger."
Note that "Type C" is also compatible with Eaton BR type breakers.
This would include GTE Sylvania breakers labeled as "Type C" as the two makes were using the same manufacturing to create their breakers during this period of time (Connecticut breakers)
The callout should be EATON.
CUTLER-HAMMER
CUTLER-HAMMER
BASELINE DT
BASELINE DT
As noted above, Eaton owns Cutler-Hammer. This can be tricky when distinguishing between BR-type breakers and load centers and CH-type breakers and Load Centers.
The "Cutler-Hammer" callout in the Basline DT refers to original Cutler Hammer (CH) load centers and newer Eaton CH-type load centers
BREAKERS
BREAKERS
By far, the easiest way to identify a CH type panel vs a BR type panel is by the breakers:
CH breakers have tan handles.
Will have the prefix "CH" on the model number.
Note that CH breakers can have either Eaton or Cutler-Hammer logos on them so looking for tan handles and the CH prefix is the key.
THINNING BREAKERS
THINNING BREAKERS
Eaton (CH) regularly manufactures the following types of standard circuit breakers:
Single pole breaker
2 pole breaker
Duplex breaker
Triplex and Quadruplex breakers are not available for this load center make.
PANEL LABELING
PANEL LABELING
Notice the label says "Loadcenter Type: CH." This tells us that this would be called out as CUTLER_HAMMER TAN in the design tool.
CALLOUT EXAMPLES
CALLOUT EXAMPLES
Example 1:
In the photo to the right, just below the breaker handle, the branding reads "Eaton" This can be deceptive because Eaton also owns Cutler-Hammer. The key to this is two things:
Tan han(dle) = Cutler-Ham(mer)
The rhyme is a little rough, but it makes it easier to remember.
A prefix of "CH" will mean Cutler-Hammer
The callout should be CUTLER-HAMMER
Example 2:
In the photo to the right there is no indication of branding. With Cutler-Hammer, we can call it out completely based on visual.
Tan han(dle) = Cutler-Ham(mer)
The callout should be CUTLER-HAMMER
Example 3:
In the photo to the right there is no indication of branding. Additionally, the handle itself is not tan, only the handle-tie. Regardless, you could still call a tan handle-tie a "tan handle," so:
Tan han(dle) = Cutler-Ham(mer)
The callout should be CUTLER-HAMMER
SIEMENS
SIEMENS
BASELINE DT
BASELINE DT
Siemens owns ITE. There are no special considerations or distinctions that need to be made between Siemens and ITE breakers, they are cross compatible.
The "SIEMENS" callout in the Basline DT refers to SIEMENS type breakers.
Likewise, the "ITE" callout in the Basline DT refers to SIEMENS type breakers.
BREAKERS
BREAKERS
Siemens breakers can be tricky to spot at first, until you've seen enough to know the trade marks.
Siemens breakers have slanted "on/off" indicators printed vertically:
O O
N F
F
Will have the prefix "QP" on the model number.
Sometimes, it may have "MP" as the prefix in reference to Murray, a manufacturer that was acquired by Siemens/I-T-E many years ago.
THINNING BREAKERS
THINNING BREAKERS
Siemens regularly manufactures the following types of standard circuit breakers:
Single pole breaker
2 pole breaker
Duplex breaker
Triplex breaker
Quadruplex breaker
PANEL LABELING
PANEL LABELING
Notice the label says "SEIMENS" in bold at the top.
CROSS COMPATIBLITY EXAMPLES
CROSS COMPATIBLITY EXAMPLES
Example 1:
In the photo to the right, just below the breaker handle, you can see a prefix "Type MP." This is associated with Murray/Arrow-Hart branding.
The callout should be SIEMENS.
Example 2:
In this photo, there are two giveaways. The branding indicates "I-T-E," which is the brand that was succeeded by Siemens. Furthermore, the model number prefix is "QP," a prefix associated with Siemens style breakers.
The callout should be SIEMENS.
Example 3:
This breaker is branded "Gould." Gould was a subsidiary of I-T-E, in fact this is indicated just below the Gould branding.
The callout should be SIEMENS.
SQUARE D HOM
SQUARE D HOM
BASELINE DT
BASELINE DT
As noted above, Square D Manufactures two lines of models, HOM and QO. They are not cross compatible with each other so it is important to distinguish the two.
There are separate call outs for Square D HOM and Square D QO
BREAKERS
BREAKERS
One easy way to identify HOM type breakers is with the model number.
Will have the prefix "HOM on the model number.
THINNING BREAKERS
THINNING BREAKERS
Square D HOM regularly manufactures the following types of standard circuit breakers:
Single pole breaker
2 pole breaker
Duplex breaker
Triplex breaker
Quadruplex breaker
PANEL LABELING
PANEL LABELING
Any time you see "Homeline Load Center," This will mean that Square D Type HOM breakers are to be used.
SQUARE D QO
SQUARE D QO
BASELINE DT
BASELINE DT
As noted above, Square D Manufactures two lines of models, HOM and QO. They are not cross compatible with each other so it is important to distinguish the two.
There are separate call outs for Square D HOM and Square D QO
BREAKERS
BREAKERS
One easy way to identify QO type breakers is by their handle style
Look for 2 pole breakers. They will have only a single handle on the right side instead of two handles that are tied together as is the case on most 2 pole breakers by other manufactures.
THINNING BREAKERS
THINNING BREAKERS
Square D QO regularly manufactures the following types of standard circuit breakers:
Single pole breaker
2 pole breaker
Duplex breaker
Triplex and Quadruplex breakers are not available for this load center make.
PANEL LABELING
PANEL LABELING
Notice the label says "QO Load Center" in bold at the top. This will mean that QO type breakers are to be used.
DISTINGUISHING BETWEEN HOM AND QO
DISTINGUISHING BETWEEN HOM AND QO
The image on the right shows a 2 pole HOM type breaker beside a 2 pole QO type breaker. Note how they are similar:
Both have the Square D logo visible (occasionally QO type breakers may note bare this logo)
Both are 2 pole breakers rated for 20A
That is where the similarities end. Now lets take a look at how they are different:
The HOM breaker has the "HOM" breaker type on the label.
Most QO type breakers will not give any similar "Type QO" indication, so you will need to rely on load center labeling and visual inspection of the breakers alone.
The HOM breaker has two handles that are tied together with a tie bar making it effectively one handle.
The QO breaker only has a single handle on one side of the breaker.
QO type breakers have an On/Off indicator window which is unique to QO (see green box).
HOM does not have any such window.
CALLOUT EXAMPLES
CALLOUT EXAMPLES
Example 1:
In the photo to the right, just below the breaker handle, you can see the On/Off indicator window which is unique to QO type breakers.
The callout should be SQUARE D QO.
Example 2:
In this photo, the breaker type is called out as "HOMT" meaning Homeline Tandem.
The callout should be SQUARE D HOM.
Example 3:
This photo demonstrates labeling that is a little trickier to read. Just below the bus schematic, there is a list of compatible breaker types. We can see part of this list calling out "HOMT," so we know this means Square D HOM:
The callout should be SQUARE D HOM.
Example 4:
The load center labeling shown to the right shows several markers of QO branding.:
Load center is titled as "QO LOAD CENTER" at the top.
The model number starts with "QO2"
The labeling indicates to "use only Square D Type QO"
The callout should be SQUARE D QO.
GENERAL ELECTRIC (GE)
GENERAL ELECTRIC (GE)
BASELINE DT
BASELINE DT
GE is a self contained callout. It will not be compatible with any other load centers.
BREAKERS
BREAKERS
The easiest way to identify GE breakers is the distinct GE logo.
THINNING BREAKERS
THINNING BREAKERS
GE regularly manufactures the following types of standard circuit breakers:
Single pole breaker
2 pole breaker
Single pole thinline model
2 pole thinline model
PANEL LABELING
PANEL LABELING
Notice the GE trademark logo near the top.
Example 1:
In the photo to the right, the GE logo is very small but visible next to the left "ON" indication label.
The callout should be GE.
Example 2:
In this photo, there are two main indicators:
The GE logo is barely visible (see red box)
The breaker is a thin-line breaker; GE is the only manufacturer that still manufactures these.
The callout should be GE.
Example 3:
In the photo to the right, you can see a 2-pole thin-line breaker that is the same size as a normal 1P breaker which indicates that this breaker is the thin-line 2P offered by GE.
The callout should be GE.
LEVITON
LEVITON
BASELINE DT
BASELINE DT
Leviton is a self contained callout. It will not be compatible with any other load centers.
BREAKERS
BREAKERS
Leviton is easy to identify by color alone. They are the only common residential manufacturer using all white breakers currently.
THINNING BREAKERS
THINNING BREAKERS
Leviton does not manufacture any type of duplex, triplex, quad or thin line breaker currently.
STAB-LOK & FEDERAL PACIFIC
STAB-LOK & FEDERAL PACIFIC
BASELINE DT
BASELINE DT
Take time to evaluate your load center and what is the best method of interconnection with these brands. For load centers with a main breaker we can look to land a load side breaker, for split busses we can check for a supply side breaker. If using a breaker follow the breaker protocol listed below under "Replacement Breakers" to select the proper one for interconnection.
For these load centers in Oregon we must default to a supply side tap. Check with a lead if you are unsure about your interconnection as these are more unique load center situations.
BREAKERS
BREAKERS
Federal pacific breakers are identifiable by the orange handles.
REPLACEMENT BREAKERS
REPLACEMENT BREAKERS
Original Federal Pacific breakers are no longer UL listed, meaning they are not considered code compliant or safe to use, however, we may still call out breakers for Stab Lok/Federal Pacific panels using classified and listed replacement breakers:
These breakers are considered safe to use and code complaint
When calling for a Federal Pacific breaker, make sure to use the following to make your callout:
Make sure the replacement breaker is a type UBIF breaker (model prefix)
Make sure it is a gray plug in type breaker.
The orange handle models are the old style that is no longer listed.
PANEL LABELING
PANEL LABELING
These panels often bare both the Stab-Lok brand name and Federal Pacific Electric Companyh Logos.
ZINSCO & SYLVANIA
ZINSCO & SYLVANIA
BASELINE DT
BASELINE DT
Default to a supply side tap for this type of load center but note that a load side breaker can still be called out for these load centers in all areas outside of Oregon:
BREAKERS
BREAKERS
Zinsco breakers are identifiable by the color coded handles indicating different breaker ampacities, and the thin handles.
REPLACEMENT BREAKERS
REPLACEMENT BREAKERS
Original Zinsco type breakers are no longer UL listed, meaning they are not considered code compliant or safe to use, however, we may still call out breakers for Zinsco panels using classified and listed replacement breakers:
These breakers are considered safe to use and code complaint
When calling for a Zinsco breaker, make sure to use the following to make your callout:
Make sure the replacement breaker is a type UBIZ breaker (model prefix)
Make sure it is a gray plug in type breaker.
The colored handles will be the old make which is no longer listed.
PANEL LABELING
PANEL LABELING
These panels will bare the signature Zinsco logo for earlier models and Sylvania for later models.
Note that Sylvania also has significant overlap with Bryant, Challenger, and I-T-E. The term "Zinsco" is used to describe the style of busing and breakers equipped on these panels.
NON-ZINSCO SYLVANIA MODELS
NON-ZINSCO SYLVANIA MODELS
As stated above, Sylvania has also been associated with the likes of Bryant and ITE at various times and therefore can have compatibility with either Eaton or Siemens.
You will need to use your discretion:
Are there mainly siemens type breakers in the panel?
Are there compatible breakers on the compatible equipment label with prefixes associated with either Siemens or Eaton? (i.e. the label says "Use BR type breakers" meaning Eaton BR)
This is an example of a Sylvania branded load center compatible with BR type breakers (BR is named for Bryant).
PUSHMATIC
PUSHMATIC
BASELINE DT
BASELINE DT
Default to a supply side tap for this type of load center but note that a load side breaker can still be called out for these load centers in all areas outside of Oregon:
BREAKERS
BREAKERS
Pushmatic breakers are identifiable as they are the only known residential manufacturer to use push button type breakers rather than a standard switch with a magnetic tripping mechanism.
REPLACEMENT BREAKERS
REPLACEMENT BREAKERS
Original Bulldog/Pushmatic breakers are no longer UL listed, meaning they are not considered code compliant or safe to use, however, we may still call out breakers for Pushmatic panels using classified and listed replacement breakers:
These breakers are considered safe to use and code complaint
When calling for a Pushmatic breaker, make sure to use the following to make your callout:
Make sure the replacement breaker is a type UBIP breaker (model prefix)
Make sure it is a gray breaker model.
The all black models are the old style that is no longer listed.
PANEL LABELING
PANEL LABELING
These panels will usually have the Pushmatic logo somewhere on the exterior of the panel. You may also see "I-T-E" or "Bulldog"
PRE-QUIZ
PRE-QUIZ
APPLIED Walk-throughs
APPLIED Walk-throughs
EXAMPLE 1:
EXAMPLE 1:
In this exercise, we are focusing on breaker callout only. Please note the following:
Breaker interconnections require 2 available spaces for PV.
Outdoor Breaker interconnections are the most preferred interconnection type when possible.
Make/Model callout is crucial to getting this right.
First, let's look for 2 available spaces for a backfeed breaker.
Looking at the images with the deadfront (cover) on can help us determine this, but note that you should still confirm that there are actually available stabs under these knock outs.
Now we can confirm that there are 2 stabs available for our PV breaker. Now we need to determine the make/model callout:
We can see the yellow Square D logo, so we know it is either HOM or QO.
The 2-pole breaker highlighted to the right has 2 handles fused together using a handle tie which is standard for Square D HOM.
We should be able to further confirm this using the labeling.
We're looking for indications of what breakers to use. As highlighted on the image to the right, the labeling indicates that this load center accepts Type HOM.
The callout should be SQUARE D HOM.
EXAMPLE 2:
EXAMPLE 2:
Remember, for this exercise, we are focusing on breaker callout only. More on different interconnection types and calculations will come later.
First we need to determine that the load center has enough space for a 2P breaker.
Now we need to call out the make/model. This one should be fairly straight forward:
Tan Handle = Cutler Hammer
Again, we can further confirm this with the load center labeling. The make is highlighted in the photo to the right.
The callout should be CUTLER-HAMMER.
EXAMPLE 3:
EXAMPLE 3:
Remember, for this exercise, we are focusing on breaker callout only. More on different interconnection types and calculations will come later.
First we need to determine that the load center has enough space for a 2P breaker.
It looks like there are two knock outs toward the bottom of the bus which is just enough space to fit a 2P breaker if we move one of the single space breakers over to the other side of the bus.
Now we need to call out the make/model. There is one visual cue that can help us come to a conclusion:
The On/Off labeling has a vertical orientation which is consistent only with Siemens.
As always, we still need to check the labeling to be sure. This load center make is I-T-E.
I-T-E was succeeded by Siemens which confirms that Siemens will be compatible.
The callout should be SIEMENS.
CALLING OUT MAIN BREAKERS
CALLING OUT MAIN BREAKERS
WHEN IS IT NEEDED?
WHEN IS IT NEEDED?
There are a few design applications where a new/replacement main breaker may need to be sourced:
Anytime we need to derate in order to accommodate backfeed.
Anytime we need to protect a sub panel being supplied by feed through lugs with no existing main breaker.
Anytime we need to bring a service up to current code.
1. DERATES
1. DERATES
When a supply side connection is not an available option to overcome insufficient backfeed, you can consider a derate:
Used to increase the allowable backfeed by downsizing the main breaker.
See Load Side Connections for a detailed guide on performing derates and when they can be applied.
2. PROTECTING SUB PANEL FEED-THROUGH LUGS
2. PROTECTING SUB PANEL FEED-THROUGH LUGS
When we have a sub panel with no main breaker feeding from the bottom lugs of the MSP such as what is depicted to the right, extra precaution has to be taken.
NEC 705.12(B)(3)(6): Connections shall be permitted on busbars of panelboards that supply lugs connected to feed-through conductors. The feed through conductors shall be protected with one of the following methods:
The sum of the main breaker and the inverter backfeed will not exceed the rating of the feed-through conductors
or
An OCPD (main breaker) will be installed to protect these feeders.
See Load Side Connections for a detailed guide on performing load side connections while protecting sub panels supplied by feed through lugs.
3. 2020 NEC SERVICE REQUIREMENTS
3. 2020 NEC SERVICE REQUIREMENTS
The 2020 edition of the NEC introduced some new requirements regarding service disconnects. Not all jurisdictions using the 2020/2023 will require us to upgrade older services but some of them might, so it is important to know the updated code specifics regarding services.
Below are the new articles and updates from the 2020 text.
(2020 NEC) 230.85 Emergency Disconnects:
For one- and two-family dwelling units, all service conductors shall terminate in disconnecting means having a short-circuit current rating equal to or greater than the available fault current, installed in a readily accessible outdoor location. If more than one disconnect is provided, they shall be grouped.
2017 NEC and prior:
There was previously no requirement for there to be an accessible emergency disconnecting means outdoors. In many older markets such as Virginia, Oregon, South Carolina, etc., you will often see "stand alone" meters, meaning that the main disconnect/MSP is indoors somewhere which was allowed in older versions of the code and may be allowed to be grandfathered in depending on the jurisdiction.
The principle difference is that the 2020 NEC requires an outdoor accessible emergency service disconnect.
See Electrical Code Violations for more details on updated code specifics regarding service requirements.
To fully learn this concept, we will dive into some real examples. These examples include some accessory information regarding PV interconnection that is expanded on more in depth specifically in Load Side Connections, however, this segment of training will mainly focus around main breaker callouts.
EXAMPLE 1:
EXAMPLE 1:
In this example, the meter/main combo is rated for 200A/200A. In order to accommodate 70A of backfeed, the main breaker will need to be derated.
See Load Side Connections for details about backfeed and load side bus bar connections.
Where do we even start?
It is best to start by looking at the existing main breaker and load center looking for the following:
What is the make of the load center
Is there a visible model number to go off of for the main breaker that we can derive the model prefix for the new, lower rated breaker from.
In this example, there's not a visible model number on the main breaker but we can see some breakers indicating that this is a Square D model, most likely HOM type.
Let's move on to the panel labeling. Often, model numbers for acceptable replacement main disconnects will be listed somewhere on this label. As you can see, there is a lot of additional information on this label that is not as relevant to what we are trying to do with PV design.
Let's narrow in on what we need.
Right below the typical wiring diagram, there is information for compatible breakers for both branch breakers and main disconnects.
Do you see where compatible main breaker models are listed on this section of the labeling?
Now we know we need to look for a QOM2 type breaker. Let's use google to make sure we got this right.
Plug in the needed prefix and the breaker rating and you should get your result.
now simply do a visual inspection to be sure. Do the profiles of these breakers match?
Yes, this is definitely the breaker we need to source for this job.
Make sure to add the model number to your data collection. This can be important because, even though most replacement breakers can be located in the design tool, there may be instances where a needed main breaker has not been indexed in the design tool and you may need to enter this piece in manually if that is the case.
The model number is QOM2150VH
Luckily, this appears to match one of the new main disconnects available in the design tool.
EXAMPLE 2:
EXAMPLE 2:
In this example, we have a meter main with feed through lugs and there is no existing breaker protecting the sub panel. The designer needs to designate a means of protection such as a main breaker to protect the sub panel.
See Load Side Connections for details about backfeed and load side bus bar connections.
Here's a view of the feed through conductors. The preferred method of protection for the sub panel will be a main breaker installed in the sub panel enclosure, but there are alternatives that can be considered if this is not possible:
The feeders can be relocated off of the feedthrough lugs onto a breaker in the MSP enclosure.
The main breaker may be derated such that the combined sources (Utility supply and PV) will not exceed the feed through conductor's rating.
Looking at the interior sub panel, there appears to be a knock out meant for a main breaker. Now we just need to determine a compatible model.
Based on the breakers visible in this panel, we know it is a Square D model, most likely HOM. What is the next step?
Check the panel labeling for compatible main disconnects.
Can you spot where the main disconnect info is on this sticker?
Similar to the last example, we're looking for a QOM-VH style breaker.
We always need to ensure that the correct breaker model for the desired disconnect rating exists before we proceed.
For this example, we'll use QOM2150-VH
This is the same piece as the last example.
EXAMPLE 3:
EXAMPLE 3:
This example has a similar set up: a meter main with feedthrough lugs and no existing main breaker in the sub panel.
See Load Side Connections for details about backfeed and load side bus bar connections.
Remember, the preferred method of protection for the sub panel will be a main breaker installed in the sub panel enclosure, but there are alternatives that can be considered if this is not possible:
The feeders can be relocated off of the feedthrough lugs onto a breaker in the MSP enclosure.
The main breaker may be derated such that the combined sources (Utility supply and PV) will not exceed the feed through conductor's rating.
This sub panel does not have a designated knockout for a main breaker.
There is space on the bus bar that we could potentially use a typical plug-in 2P breaker as a main breaker to protect this panel, but there are considerations with this:
We would need to ensure that the breaker we choose can accept these feeders
Usually, 2P plug-in types breakers only go up to about 125A which will only allow wires sized up to 2/0 which is used for services up to 150A.
All breakers on the bus would need to be moved down
no breakers could be placed on the bus in the two spaced directly next to the new plug-on main.
It is also possible to relocate the feeders onto a 2P breaker in the MSP.
The next step would be to investigate the service rating. Back outside at the meter/main, the main disconnect is 150A. This means we can most likely use a standard 2P breaker rated for 125A to protect the sub panel. Now the question becomes: should we land the new main breaker in the sub panel or the MSP enclosure?
In this example, it will be much easier for the installers to simply install a new 2P breaker at the bottom of the bus bar in the MSP right beside the new PV breaker
This is easier than trying to access the interior sub panel and move breakers around for the new main breaker in the sub panel.
The main breaker in the MSP is Siemens, so we know we need to source a Siemens breaker. Use google.
Make sure to record the part number for your data collection.
The next thing to consider is that when we are using a plug-in branch breaker as a main breaker, we will typically need to provide a breaker hold down kit or retainer clip to mechanically fasten the breaker to the enclosure.
Again, this should just be a simple google search.
Make note of the model number. Also ensure that the specs say it is compatible with the breaker we are sourcing.
It appears that the design tool does have the needed breaker indexed.
Always make sure to check the model number against your data collection.
The breaker is here at the bottommost spot on the BOM, but no hold down is populated. We need to add this manually.
Here is what it should look like.
Make sure to follow the format of all other item descriptions: [Brand][what the item is using short specs],
Always include model numbers to avoid any confusion.
Here is what the final installed product looks like:
TAKE A MOMENT TO TEST YOUR KNOWLEDGE
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