Gray
I am going to have a Eaton CHSPT2ULTRA Surge Protection appliance installed, and I also need two additional circuits added to total this:

a. Q250 50-Amp Double Pole Type QP Circuit Breaker (for Eaton CHSPT2ULTRA Surge Protection)

b. Q230 30-Amp Double Pole Type QP Circuit Breaker (for whole house humidifier)

c. Q120 20-Amp Single Pole Type QP Circuit Breaker (for additional wall receptacle)

The existing load center is Siemens G3040L 1200 (30-Space 40-Circuit) and I do not have any room left for the two 240v circuits.

(Siemens does make a P4040L 1200 40-Space 40-Circuit load center)

My question: Given that the installation of the Eaton CHSPT2ULTRA Surge Protection is supposed to be “first in line” for subsequent loads, is it more practical to install a larger load center, or a sub-panel?

Thank you.
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Geoff Z
A new load center is an expensive proposition for what you are trying to accomplish. The existing load center is probably UL listed for tandem breaker installation. However that can be a slippery slope as they need to be arranged appropriately. Lightly loaded circuits should be chosen as tandems don’t dissipate heat as well. You also have to be careful with phasing as you don’t want to lopside the load on your neutral. You want the neutral as close to zero as possible. Not super critical in a residential application but something to keep in mind. Nowhere in the Eaton instructions do I see a mandate for the location of breaker feeding suppressor. Simply that it is best to keep wiring short as possible avoiding bends. If a sub panel were to be added I don’t see in the instructions if a second suppressor would become necessary. A picture of the panel would help to be able to offer anything more. The instructions do say they are not all inclusive and offer a tech support number as well. 

Instructions:
http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/ib00414001y.pdf
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Gray
Here is a photo of the panel; it is located in the garage which is fully insulated and drywalled. The top right is an exterior mounted RV receptacle that is seldom used, may 3 - 5 days a year. The Dryer circuit (low right) is never used, since we use a NG dryer. (I still would leave that circuit intact on the off chance we ever sell the house so it would not have to be addressed at that point in time with everything else that accompanies a real estate transaction.)

All of our interior and exterior lighting is LED, so all of those circuits are lightly loaded.

IMG_0369 2.jpg
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Birken Vogt
Reference the sticker inside the door.  The first 5 levels can have tandem breakers.  Plus there is one empty spot.  Lots of ways to skin this cat.
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JayH
Ten of the thirty slots can accommodate twin breakers. One twin breaker taking up one slot can feed two independent circuits. Replacing ten single breakers would gain you up to ten free slots. The slots are keyed. You can't put the twin breakers anywhere, only in designated slots. The flag terminals on the busbar capable of twin breakers have a notch and the cover plate should indicate which slots are twin-capable. You'll almost certainly have to move some circuits around. The circuits most appropriate for twin breakers are single 120V lighting and receptacle circuits. Part number Q1515 for twin 15-amp and Q2020 for twin 20-amp. There are other combinations including "dual-twin" that take up two slots and accommodate two 240-volt circuits, but I'd recommend using the twin 15 and twin 20 amp units as they're much more common and less expensive.
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Gray
All of you guys are fantastic. Thank you very much.
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Geoff Z
Easy Peasy!
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UPS
Gray wrote:
I am going to have a Eaton CHSPT2ULTRA Surge Protection appliance installed, and I also need two additional circuits added to total this...

My question: Given that the installation of the Eaton CHSPT2ULTRA Surge Protection is supposed to be “first in line” for subsequent loads, is it more practical to install a larger load center, or a sub-panel? Thank you.


I
Geoff Z wrote:

.... Nowhere in the Eaton instructions do I see a mandate for the location of breaker feeding suppressor. Simply that it is best to keep wiring short as possible avoiding bends.


I have one of the Eaton tech brochures - and the breaker location suggested in it is to be as close as possible to the the surge protector to keep the leads short:

The SPD still must be installed
using a dedicated unused or
new circuit breaker in an
available space closest to the
location where the SPD is to
be installed.
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Gray
I would love to have the SPD flush mounted inside the load center. I have no idea if that is even possible (sufficient room).

Thanks for the input!
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Geoff Z
UPS wrote:


I
UPS wrote:


I have one of the Eaton tech brochures - and the breaker location suggested in it is to be as close as possible to the the surge protector to keep the leads short:

The SPD still must be installed
using a dedicated unused or
new circuit breaker in an
available space closest to the
location where the SPD is to
be installed.


Yes we understand it the same way. You simply did a much better job explaining it than I did. The breaker needs to be directly adjacent to the SPD. With the shortest wiring possible between them with no sharp bends. 

My understanding has always been that the breaker and SPD should be at the very top buss position in the load center. The way it reads that does not seem to be the case? Any position on the buss would be ok then? That was what I was poorly trying to get at in my earlier post. 

Does the tech brochure address a two load center application? I would rationalize that a sub panel where the sub feed breaker originates from a load center with an SPD would also be protected?

Conversly if it were to be two service panels fed out of a 320 meter can for example. That would make me feel like each panel should have its own SPD?
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JayH
Geoff Z wrote:


My understanding has always been that the breaker and SPD should be at the very top buss position in the load center. The way it reads that does not seem to be the case? Any position on the buss would be ok then? That was what I was poorly trying to get at in my earlier post.


The action of a surge protector is to clamp excess voltage. This is done with a MOV, gas tube, SCR, or similar device that produces a high-current short to ground when a peak voltage is exceeded. The short-circuit is removed within a half-cycle, about 8.3 milliseconds tops, when the next zero-crossing occurs. The clamping action is brief enough that the breaker connecting the SPD to the load center doesn't trip. 

Ideally you want the SPD at the position closest to the incoming feed so that the shunt current is clamped before following the busbar to load-bearing breakers. This is not necessarily the top position, but it is if the incoming feed lugs are at the top. Note in the photo of Gray's panel that the main breaker is at the bottom of the panel, so the best place for the SPD would be in one of the bottom slots in this case.

Practically, if mechanical considerations prevent putting it at the ideal location, there will usually be enough inductance between the source of the surge and the SPD that the protection will be virtually the same. Keeping the wires between the SPD and the load center short and direct (don't coil them!) is more important than the specific slot.

Hypothetical: A tree branch falls and causes a short in the power company's distribution wiring resulting in a fast-rising voltage spike. There are a few hundred feet of wire between the fault and the load center. Clamping the spike at the top vs. bottom of the busbar isn't critical as the reactance of the busbar is a small fraction of the overall reactance to the fault. However. coiling the wires between the SPD and the breaker forms an inductor that, at the high frequency of a fast-rising pulse, could reduce its effectiveness.

TL😃r: Keep the wiring short and straight. If possible, mount its breaker in the slot closest to the incoming feed.

Geoff Z wrote:

Does the tech brochure address a two load center application? I would rationalize that a sub panel where the sub feed breaker originates from a load center with an SPD would also be protected?


It would protect the sub-panel and its loads if the fault is on the utility side of the on-premise wiring which is almost always the case.

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Geoff Z
Very good explanation. When I say top of buss I do mean closest to incoming feed. Thank you for clarifying that better than I did. Yes with Gray’s panel the bottom buss position closest to main and incoming feed would be best. 

So in my second scenario with a 320 meter enclosure having 2 separate SE conductors going to 2 separate 200a SE rated load centers would you put a SPD at the incoming feed of both panels? Or would one SPD on the incoming feed of 1 panel be sufficient? I ask because in our area that is how electrical services are built on larger homes. 
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Gray
Geoff Z wrote:

My understanding has always been that the breaker and SPD should be at the very top buss position in the load center.


JayH wrote:
Ideally you want the SPD at the position closest to the incoming feed so that the shunt current is clamped before following the busbar to load-bearing breakers....Keep the wiring short and straight. If possible, mount its breaker in the slot closest to the incoming feed.


Geoff and Jay,

Thank you for the professional elucidation. That the SPD is not (in principal) positional agnostic is something that I thought was correct, but then (like Geoff pointed out), I could not find in the device literature. The point of short and straight wiring is understood and will be accomplished.

All of our utilities are underground supply so that is logical for the bottom feed on the panel.

Thank you again gentlemen.
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JayH
Geoff Z wrote:

So in my second scenario with a 320 meter enclosure having 2 separate SE conductors going to 2 separate 200a SE rated load centers would you put a SPD at the incoming feed of both panels? Or would one SPD on the incoming feed of 1 panel be sufficient? I ask because in our area that is how electrical services are built on larger homes. 


I'd put one at each 200A load center in that case. You want minimum impedance (AC version of resistance) between the SPD and the connected loads. While the SE conductors are of low resistance, their inductive reactance to a fast rising spike would limit their protection with regard to the remote panel. If a couple of inches of busbar to the feed lugs within a panel makes a significant difference, you can bet a few dozen feet of SE cable will as well. Note that this is a different scenario than a single 200A service panel feeding a subpanel where a single SPD at the service panel would suffice.

Keep in mind that there are surges and then there are SURGES. A surge that originates far away will be handled by an SPD in one panel. A nearby lightning strike is a different story and having an SPD at each panel is likely to save some gear. A direct hit to the pole outside your house is pretty much game over no matter what you do.
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Geoff Z
Note that this is a different scenario than a single 200A service panel feeding a subpanel where a single SPD at the service panel would suffice. 

Agreed. Thank you thank you for confirming my understanding. Yes in a sub panel application one SPD is sufficient. Whereas with 2 service panels an SPD at each panel is a good recommendation. That is how I have always advised customers. I appreciate having the discussion. Always good to revisit a subject. 
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Gray
I had intended to incorporate Type 1 (Meter Socket, Leviton 50240-MSA), Type 2 (as discussed), and Type 3 (appliance receptacle) protection. With so many micro-processors in everything (reefers, washer/dryer, etc) I wanted to be a belt, suspenders and velcro tab kind of guy.

My utility provider will not allow Type 1's installed on their meter base. I already have the type 3's installed, and now that the knowledge has been secured I can move forward on this.
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Cobranut
I have a 400a service disconnect feeding a 400a transfer switch. 
I'd like to add an SPD to the input of the transfer switch.
If I can find a 50a+ panel mount breaker, would I be ok putting the SPD inside the disconnect box, or would it be better in the  transfer switch box?   There is only about 2 feet of parallel 4-0 cable between the two. 
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Geoff Z
I don't know that the UL Listing for the disconnect or transfer switch would allow the SPD installed within their enclosures? It could be argued that you are doing a retrofit that is beyond its intended use. Thus voiding the warranty. If it is an existing service you might not care about that but it would not be readily visible to trained or untrained personnel to confirm the status light is still lit and it is functioning. An SPD can be destroyed when clamping fault current. Which is its purpose. You would much rather be replacing it than boards and components in sensitive equipment.  I would still think the SPD mounted on the panel(s) as close to the incoming feed as possible would still be your best option. Explain the service on the load side of the transfer switch? Are you coming off in parallel and feeding two 200a SE rated load centers? Or is there one 400a load center?
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Geoff Z
Disclaimer: I am far from the expert on this subject. I'm just an electrician with real world experience that has been around quite awhile. I do the best I can to understand the equipment I sell. Jay H has explained this subject to us from a more an Engineering view. Fault currents, impedance, inner workings of the SPD, and the like. I have benefited more by this conversation and picking his brain than anyone. I come from the viewpoint if components are not installed properly bad things can happen. Bad things can harm people and property and cost a lot of money. I just always want to get better at what I do. You guys help me do that. We all care about that which is why we are all here. I love that we can take a subject like this and everybody chip in until we all have a better understanding. Causes me joy!
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Gray
"Just" an electrician. As Marion Morrison was wont to say: "Not hardly, Pilgrim.

It is no small thing that you so graciously share your money (it costs you to keep this site up and running), time, knowledge and expertise to Joe Shmucketelli's like me. And you provide a venue where other professionals visit and generously and selflessly add to the wealth of information.

No "just" about it.

I am sincerely thankful for the service that you and the others provide.
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Cobranut
Geoff,

Here are a few pics of the disconnect and the switch.

I guess I worded things incorrectly.  What I meant was to mount the SPD through the side of the enclosure, alongside a breaker mounted in the same way.

I tend to think it would be slightly better to wire it to the transfer switch, as the additional inductance between the disconnect and the switch would help the SPD to better clamp a spike. 2017-03-25 11.51.24.jpg  2017-03-25 11.51.28.jpg  2017-03-31 14.29.39.jpg  2017-04-01 18.35.54.jpg 
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JayH
Cobranut wrote:
I have a 400a service disconnect feeding a 400a transfer switch. 
I'd like to add an SPD to the input of the transfer switch.
If I can find a 50a+ panel mount breaker, would I be ok putting the SPD inside the disconnect box, or would it be better in the  transfer switch box?   There is only about 2 feet of parallel 4-0 cable between the two. 


If the disconnect box is the service equipment where the grounding electrode conductor attaches and the ground-to-neutral bond exists, I'd put it there if at all possible.

Does the transfer switch include a built-in load center? If so you could put it there but it would be on the T1 and T2 side as I don't think there's an easy means to add a breaker to the N1 and N2 side on most transfer switches.
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UPS
JayH wrote:


If the disconnect box is the service equipment where the grounding electrode conductor attaches and the ground-to-neutral bond exists, I'd put it there if at all possible.

Does the transfer switch include a built-in load center? If so you could put it there but it would be on the T1 and T2 side as I don't think there's an easy means to add a breaker to the N1 and N2 side on most transfer switches.


There are models from Eaton designed to be used ahead of the service disconnect, which don't need a breaker.
There is large amount of useful technical info and model description on the Eaton web site here:
https://www.eaton.com/Eaton/ProductsServices/Electrical/ProductsandServices/Residential/SurgeProtection/index.htm

Browse the links under Surge Protection Products on the left.
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Geoff Z
A very nice installation! Yes mounting the breaker and SPD surface mount is best. I do like the idea of putting it at the disconnect. It seems to me you would have to tap the SPD breaker feed under the same lugs as the service conductors? Are those lugs dual wire rated? In my opinion that would be fine as you are terminating to a over current device. NEC doesn’t see it that way though unless the lugs are rated for it. Would the inspector accept that? If not are the lugs in the transfer switch dual wire rated? If so you could feed from there. Generac 400a transfer switch are dual wire lugs, maybe Thompson lugs are also? Maybe one of the models that JayH suggests might be the way to go and avoid all the tap concerns. 
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Cobranut
Thanks Geoff.  That's my DIY install, with lots of help from this forum, and a co-operative and helpful local inspector.

I looked at the Eaton Type 1 SPD's, and I like the idea of them not needing to be wired through a breaker.
It would be much easier to install at the transfer switch.  As I recall, the blade terminals that feed the sensing circuit in the switch are attached with screws into the utility terminal blocks.  Adding ring terminals under these screws would be a simple and direct method to make the connections, and I could mount the unit through the top of the switch.
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