ION ORACLE - Consolidating Breakers

CONSOLIDATING BREAKERS

Design

1 | BREAKER CONSOLIDATION

TYPES OF BREAKERS USED FOR THINNING

Tandem breakers are simply breakers that can fit more circuits in less spaces to make more overall space on the bus bar for circuitry. Tandem is a generic term used to describe a few different types of these breakers:

Tandem/Duplex: 1 space, (2) 1-pole 120V circuits

Triplex: 2 space, (1) 2-pole 240V circuit + (2) 1-pole 120V circuits

Quad: 2 space, (2) 2-pole 240V circuit

The image to the right shows an MSP with tandems installed in the bottom 10 spaces:

Tandems allow you to fit 2 circuits in one branch breaker space.

Notice that the tandems in the bottom spaces are the same size as the single space breakers.

The purpose of all duplex/triplex/quadruplex breakers is to consolidate breaker space. There are a couple of reasons you may need to do this:

To correct code violations such as double landed breakers
When a panel is too full to accept a standard 2 pole PV breaker.

Note that not every load center will accept tandems

How do I know if a bus bar accepts tandems?

Look at the labeling:
- Model number:
  - tells you how many circuits allowed on the load center
  - Tells you how many breaker spaces (stabs) the load center has.

- Bus diagram:
  - Often indicates which stabs, if any, will accept tandems.

- Breaker compatibility table:
  - Often tells you which types of breakers can be used in the panel.

- Lastly, look for notched stabs if they are visible.
  - The diagram to the right shows what a solid stab vs a notched stab would look like.

In the example to the right:

The red highlighted stab is a solid stab that would not allow tandems.
The green highlighted stab is a notched stab that would accept tandems.

TANDEM BREAKERS

Tandem breakers are breakers that occupy a single space but allow two 1P (120V) circuits to be attached. They are also often refurred to as "duplex" breakers.

Here is a side by side comparison of a typical single pole breaker next to tandem style breaker. Note, the tandem has two separate breaker handles for the two possible circuits.

Think of it using this visual. It's really like having two breakers that are glued together.

TRIPLEX BREAKERS

Triplex breakers are breakers that occupy two spaces but allow two 1P (120V) circuits to be attached as well as a 2P (240V) circuit in the center.

Here is a side by side comparison of a typical two pole breaker next to triplex style breaker.

It can be a bit confusing to look at at first, so here's a helpful visual:

The 50A handles have a common trip tying them together.
- Think of the breaker being cut in half down the middle, but the 50A breaker (the two handles tied together) are straddling the divide.
- This breaker sits on top of two stabs meaning that together, the two 50A poles are being supplied with 240V.
The 20A handles on either side are not tied together.
- they are each only sitting on one stab. This means they each are only being supplied with 120V.

Here's another visual. Think of this like three breakers glued together.

QUAD BREAKERS

Quad breakers are breakers that occupy two spaces but allow two 2P (240V) circuits to be attached.

Here is a side by side comparison of a typical two pole breaker next to quad style breaker.

It can be a bit confusing to look at at first, so here's a helpful visual:

The 40A handles have a common trip tying them together.
- Think of the breaker being cut in half down the middle, but the 50A breaker (the two handles tied together) are straddling the divide.
- This breaker sits on top of two stabs meaning that together, the two 50A poles are being supplied with 240V.
The 30A handles have a common trip tying them together.
- This means that these handles are also straddling both stabs combining as 1 breaker being supplied with 240V.

This is basically the 2P equivalent of a tandem/duplex. Its like having two breakers glued together.

BREAKER CONSOLIDATION BY MAKE

EATON

Eaton regularly manufactures the following types of standard circuit breakers:

Single pole breaker
2 pole breaker
Duplex breaker
Triplex breaker
Quadruplex breaker

CUTLER-HAMMER

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.

SIEMENS

Siemens regularly manufactures the following types of standard circuit breakers:

Single pole breaker
2 pole breaker
Duplex breaker
Triplex breaker
Quadruplex breaker

SQUARE D HOM

Square D HOM regularly manufactures the following types of standard circuit breakers:

Single pole breaker
2 pole breaker
Duplex breaker
Triplex breaker
Quadruplex breaker

SQUARE D QO

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.

GENERAL ELECTRIC (GE)

GE regularly manufactures the following types of standard circuit breakers:

Single pole breaker
2 pole breaker
Single pole thinline model
2 pole thinline model

Notice, these breakers are a little different than what is typical of other models. Instead of having "two breakers glued together" they have breakers that are shrunk down to occupy half the space.

How does this work with the busing?

As a reminder, other makes utilize notched stabs to make individual contact with tandem circuits, but that relies on breakers being able to sit on top of typical stabs.

But if GE slim breaker only occupies half of the space, how does it contact the bus?

Take a look at the stabs of this GE panel:

in between each horizontal stabs, there are smaller inter-stabs that run vertical.

This is the GE equivalent to "notched stabs."

This is another example where only some of the spaces will allow slim breakers. Notice the top two stabs do not have the smaller inter-stabs.

This is a view of the connectors for slim type GE breakers. They clamp onto the vertical inter-stabs.

Also be sure to check the labeling:

This will be identical to how other load centers label spaces that accept tandems.

2 | WHEN TO THIN BREAKERS

MAKING SPACE FOR PV

The most common reason to thin breakers is to make space for a 2P breaker for PV interconnection:

Breaker interconnections are the most preferred method of interconnection when they are available.
The load center bus must allow tandems for this to even be considered.
You should attempt to consolidate loads to make space for PV using as few replacement breakers as possible:
- This will require you to keep notes of how many spaces are freed up by using quads, triplexes, or tandems and planning around this.

CORRECTING CODE VIOLATIONS

Reminder: what is double lugging?

More than one wire landing on a single lug on a branch breaker, main breaker or main lugs.

Using tandem breakers can be a potential solution in many cases:

The load center bus must allow tandems for this to even be considered.
Give special attention to 2P (240V) breakers as these will require some extra thought when planning how to consolidate 2P breakers that are double lugged.

WHEN NOT TO THIN BREAKERS

GFCI BREAKERS

There are no tandems that are manufactured as GFCI protection. Do not attempt to tandem any loads connected to GFCI breakers:

GFCI breakers are most easily identifiable by looking for the "test" button on the breaker.
Plan to only tandem typical breakers and leave these in place.

PANELS THAT DO NOT ALLOW TANDEMS

Before considering using tandems to thin breakers, you need to make sure that they will be compatible with the load center:

Thoroughly investigate the panel labeling.
- Look at the typical wiring diagram and see how many labeled circuits there are and compare against the number of spaces you can see in the photo of the panel with the deadfront on.
- Look at the model number for indication of spaces/circuit allowances.
- Look at the breaker compatibility list/table for breaker prefixes associated with tandems, duplexes, triplexes, quads and slims.
Look for physical evidence if there is any exposed busing:
- notched stabs
- cross stabs on GE type models.

This bus does not allow any tandems in any position according to the labeling:

Model number indicates 16-16, or 16 spaces and 16 circuits max.
The typical wiring diagram does not indicate any spaces that allow tandems and only lists up to 16 possible circuits.

Be extra careful with busing that will only allow tandems in certain positions on the bus:

compare the typical wiring diagram to what is installed on the bus side-by-side.
If tandems already occupy all spaces that allow tandems, you will need to explore other options.
Leave clear instructions for the installer that any consolidated loads would need to be moved to positions supporting tandems when consolidating on a bus like this.

Only the bottom 4 spaces on this bus would accept tandems according to the labeling.

SUB PANEL INSERTS

A sub panel insert is used primarily to relocate loads to make space for PV, correct code violations, or house OCPDs for sub panels that require protection but will not accept a main breaker.

This is done by simply installing a new sub panel to feed from the MSP and moving circuits over to breakers in the new sub panel. Most often this new sub panel will also house the new PV breaker.

Example:

This is an example of a meter/main that appears to be completely full. Remember, a supply side connection will not be available on a typical meter/main.

Normally, the first course of action with a full panel would be to look to see if any breakers can be thinned to make space for a 2P PV breaker but that does not appear to be an option here.

This breaker is feeding a sub panel, however, the interior sub panel is on an interior wall and does not have an option for a main breaker add-in.

This will make both a load side tap, and load side breaker - sub panel non viable.

So what can we do?

By completing a sub panel insert, we can relocate some of the loads and this also adds a brand new bus for us to use for interconnection:

loads were removed from the MSP to make space for a 60A 2p to feed the new sub panel.
The new sub panel will house the relocated loads and our PV.

This will be much more cost effective than completing a main panel upgrade and a lot less work than pursuing interconnection on an interior sub panel:

No drywall cuts.
Minimal breaker relocation.

A PER IS ALWAYS REQUIRED WHEN CONSIDERING A SUB PANEL INSERT.

3 | EXAMPLE WALK THROUGHS

EXAMPLE 1

In this example we have a meter/main. When you see a meter main, you should start planning for a load side connection as a supply side connection is usually not possible unless the meter/main has a solar ready position.

When viewing the photos of the panel with the deadfront off, the first thing to notice is that there are feedthrough lugs supplying an interior panel somewhere in the home.

We should also note if there are any code violations or damage to address in this panel. There do not appear to be any based on what is visible in this photo.

We will also note that the main breaker rating is 200A.

Visiting the panel labeling now, it appears that all spaces will accept tandems. It would be ideal to land PV in this panel, so we will start planning for this.

We'll also note the 200A rating of the bus.

Let's do the backfeed calculations:

(200 * 1.2) - 200 = 40A allowable

This customer's system will consist of 17 models.

17 * 1.21 * 1.25 = 25.7125A

We will round up to the nearest OCPD size of 30A

Right now, we know the following info:

Breakers in the MSP can be consolidated to make space for a 2P PV breaker.
There is adequate backfeed to support PV in the MSP.
There are feedthrough lugs present in the MSP.

Now we need to know if the interior panel can be properly protected.

This photo demonstrates that the feeders enter the sub panel from the top. This also appears to be an unfinished basement. All of these are indicators that the interior panel is remote from the MSP and we need to do everything we can to interconnect on the exterior of the home.

This is the only photo of the sub panel with the deadfront on. It does not help us see if there is a knock out for a main breaker, but it seems somewhat probable for HOM type load centers.

The labeling on the interior wall of the panel lists prefixes for compatible main breaker kits. In this case, we should choose a QOM-VH.

We will be okay to complete a load side breaker in the MSP by:

Quading breakers in the MSP to make space.
protecting the sub panel by installing a new main breaker.

This designer decided to quad two of the existing 2P breakers and land a new PV breaker on a standard 2P breaker. There are a couple things to note about this:

You should always try to complete the needed consolidation in as few breakers as possible
- In this case, the designer could have chosen to land the PV in a quad with only one of the other existing breakers.
  - This would mean that only one branch breaker needs to be sourced instead of 2.
The other consideration you need to keep in mind as the designer is that some AHJs/Utilities may have restrictions against landing PV in a quad breaker.
- This exact setup would be the best course of action in those cases.

And here's our new main breaker protecting the sub panel.

EXAMPLE 2

This MSP is not in a combination with the meter, so let's keep in mind that both supply side and load side connections will likely be available to us on this one.

Again, remember that breaker interconnections will be preferred over tap type interconnections when they are possible.

So with that in mind, we'll look to see if a load side connection will be possible before we consider pivoting to a supply side tap.

Let's start collecting some basic data. This main breaker is rated for 200A.

The bus rating is hard to read and this is the only photo the surveyor got of the labeling, however, the model number indicates 200A. We're safe calling this a 200A/200A.

let's do the math:

(200 * 1.2) - 200 + 40A backfeed allowable.

While we're still looking at the labeling, we should look to see if tandems will be allowed. According the the labeling, only the bottom half of the bus accepts tandems.

Before we move on, let's do the second part of the backfeed calculations:

23 * 1.21 * 1.25 = 34.7875

We will round up to the nearest OCPD at 40A

This means there is just enough allowable backfeed to for a load side connection to be viable.

Right now, we know the following info:

Breakers in the MSP can be consolidated to make space for a 2P PV breaker.
1. But only on half of the bus
There is adequate backfeed to support PV in the MSP.
If you look closely at the panel, there are lots of GFCI breakers that cannot be tandemed.

Now we need to plan how we can exicute a load side connection.

We only need to free up one space, so it may be tempting to try consolidating these breakers...

... or these breakers. There is a less obvious third option that is even better, and here's why:

If we went forward with one of the plans above, we would have to move around a lot of loads to make it work:

All the GFCI breakers would need to move up on the bus
Any new tandem or quad breaker would need to move down to the lower half of the bus where tandems are supported.

We should avoid shuffling circuits around like this if possible.

This is the secret third option:

Simply consolidate the PV with the existing AC.
- Call for a 30/40 quad to accomplish this.

Here's what the finish product looks like:

- The PV breaker is the outside 40A handles that are tied together.
- The AC is the interior 30A handles that are tied together.

EXAMPLE 3

Here we have a GE meter/main combo.

Note that there is 1.5 spaces available.
- The 3 visible knockouts are actually half spaces since GE slims are half spaces.
Also note that most of the non-slim breakers are GFCI and would not be able to be thinned.

All the red highlighted breakers are those that are either already slimmed or cannot be slimmed because they are GFCI rated breakers.

We can also conclude that slims could be landed in these spots if needed. Now we need to make a plan of action.

Note that technically, you can use a 2P GE slim as a PV breaker, you just need to be very careful about positioning this breaker. Extra care needs to be given in the install notes with instructions on how to do this if you ever consider using a 2P GE slim as a 240V PV backfeed breaker:

the most important factor is that the slim 2P breaker needs to be located in between stabs to ensure contact with both bus bars.
- This means you can't locate the slim at the very bottom of the bus because it will only be connected to one stab that way.
- The breaker would need to be a half space up from the bottom.

Due to this being somewhat difficult to communicate to install, it is not recommended that you pursue this type of interconnection using a slim 2P unless you absolutely have to.

This is what ended up being installed. The 30A breaker at the bottom left is the PV breaker.

What's the issue here?

The installer installed this breaker on a single stab which effectively makes this a 120V breaker being backfed by a 240V PV circuit.

The installer should have moved this breaker down by a half space to overcome this.

MAKE SURE TO GET APPROVAL AND LEAVE DETAILED NOTES IF YOU ARE USING A GE SLIM AS A PV BREAKER TO AVOID THIS SITUATION.

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