200A Panel in Garage Craziness

[Diezul]

Should probably do some more reading on the HOM2200bb and HOM2150bb. The spec sheet simply says they are for load centers and combo units rated 150a or more. No reason it shouldn't be allowed, those breakers use 4 stabs which keeps the current at or below 100a per stab. Might be worth a phone call to Square D.

150a breaker with 2/0 aluminum wouldn't be bad to install as long as you don't predict your load going over 135A.

Otherwise the 200a with 4/0 will give you 180a of allowable load. I wouldn't mess with 250mcm, your whole house isn't fed with wire that big.

With that phase converter 100 feeder isn't enough. Full load on it is like 110A.

So after doing a little more digging, it seems like I should NOT use a breaker greater than 100A on the particular CSED I have. There's different versions of the 200A CSED, and I unluckily have the first version. I found a reply from a Schneider Electric tech from their website that states:
"These larger branch breakers can ONLY be used in the CSED that show them listed on the wiring diagram of the device.
NOTE: NOT ALL CSED WILL ALLOW THE USE OF THE LARGER BRANCH BREAKERS. The specific devices will be marked for a branch breaker of 200amps Max. So these high amp branch breakers, catalog numbers HOM2150BB, HOM2175BB and HOM2200BB can be used in those specific CSED ONLY, that are rated 150amp or higher."

I also contacted a Schneider Tech, and they confirmed that I cannot use breaker HOM2150BB on the CSED SC2040M200C stating that '"the panel was only engineered for 100A max. Probably due to heat dissipation and/or wire size". But I see what you are saying, that a 2 tab 100A breaker is okay, so why shouldn't a 4 tab 150A Breaker be allowed. Logically it would be like having a 2 tab 100A and 2 tab 50A breaker, or some similar combination.

 

[ard]

Thanks for this explanation, it's really helpful and not something I've came across or considered. This is what my POCO planner is alluding to when I last spoke to her. When I inquired about service upgrade months back, I was upfront with everything and they didn't seem to care one bit, just gave me options and potential costs.

Will your poco charge you to upgrade your service to handle even the 200A service they promised at the time it was built?

So dont go demanding upgrade and 400, 600, 800 amp services. Just ask what they will charge to 'fix' what they are currently delivering.

Keep in mind- just like noobs walking into a car service department- a poco may treat a noob homeonwer differently than a knowledgeable electrican, in terms of what they must cover and what they can charge you for....

 

[wyliesdiesels]

He said he didn't care and was very adamant, he's been doing this for so long and to trust him... Also must use Copper wire, not aluminum, otherwise my house will burn down.

I also indicated my phase converter called for a 110-125A Breaker and max steady state 3 phase output would be ~64A per spec. He says that would be magic and math doesn't lie, busts out his calculator and says max ~40A 3 Phase output given ~120A single phase input. Again, very adamant. I believe his math to be misguided by using 3 as the multiplier, and not sqrt(3).

What's scary is that he is a highly reviewed Master Electrician that works on a lot of commercial/industrial projects also. This is exactly the reason why I try to research and sometimes turn to an online community for help/guidance instead of just trusting an 'Expert' to do everything. As funny as it sounds, I only trust the internet because you can usually find the answer/truth if you filter through enough. I'm greatly appreciative of everyone's help and contribution.

yup bingo

shouldve used sqrt of 3

 

[Pingel85]

I also contacted a Schneider Tech, and they confirmed that I cannot use breaker HOM2150BB on the CSED SC2040M200C stating that '"the panel was only engineered for 100A max. Probably due to heat dissipation and/or wire size". But I see what you are saying, that a 2 tab 100A breaker is okay, so why shouldn't a 4 tab 150A Breaker be allowed. Logically it would be like having a 2 tab 100A and 2 tab 50A breaker, or some similar combination.

This is due to the heat buildup in one spot of the panel. Didn’t look at your panel spec but there is a chance that there is a specific location a breaker that big must go as well. The panel might not “allow” 50a breakers next to that location, so the bus can handle the heat buildup.

 

[Diezul]

Will your poco charge you to upgrade your service to handle even the 200A service they promised at the time it was built?

So dont go demanding upgrade and 400, 600, 800 amp services. Just ask what they will charge to 'fix' what they are currently delivering.

Keep in mind- just like noobs walking into a car service department- a poco may treat a noob homeonwer differently than a knowledgeable electrican, in terms of what they must cover and what they can charge you for....

I'm not sure yet, as they haven't mentioned any number besides if I want 400A, it would be ~25-30K because of transformers/underground/etc.

Just curious, if the MSP is 200A with breaker, and service was supposed to be as such, but the POCO sizes the service conductors for way less, isn't it a big safety hazard? Or does something trip from the POCO side first? I doubt the majority of home owners would be on top of this kind of information.

 

[Diezul]

This is due to the heat buildup in one spot of the panel. Didn’t look at your panel spec but there is a chance that there is a specific location a breaker that big must go as well. The panel might not “allow” 50a breakers next to that location, so the bus can handle the heat buildup.

Makes sense. You're correct, the larger breakers 100A+ are to be located at the bottom last slot for all the models AFAIK. Thanks.

 

[Norcal]

I'm not sure yet, as they haven't mentioned any number besides if I want 400A, it would be ~25-30K because of transformers/underground/etc.

Just curious, if the MSP is 200A with breaker, and service was supposed to be as such, but the POCO sizes the service conductors for way less, isn't it a big safety hazard? Or does something trip from the POCO side first? I doubt the majority of home owners would be on top of this kind of information.

PoCo's are not under the NEC, which is far more conservative then the regs they are under, BTW, there is no overcurrent protection whatsoever on the secondary of their transformer. They have decades of experience with the smaller conductors they use.

 

[86turbodsl]

I dont reccomend buying/using used electrical materials myself anyway.
Materials are not that expensive new.

That entirely depends on what you're buying. I just bought a 3 phase breaker panel for $40 that listed for over $1000. And it looks brand new.

 

[brewchief]

Some thoughts
On your wiring plan it looks like most of the wire is shown as aluminum, I would plan instead on using copper for everything except the main feed to the panel. 10 awg aluminum may exist but it's not common, I couldn't even find it for sale on google. The receptacles that you have specified for the 20 amp circuits are not rated for aluminum wire either.

Running multiple circuits in one conduit is fine but you have to derate if over 3 current carrying wires in the conduit and then derate further if over 9 and so on.

The feed running through the attic may need to be derated due to the high ambient temperature.



You mentioned a 10-15hp air compressor, would this be 3 phase? There are some drawbacks to running something like that on a phase converter. How much air do you need and do you need it when there are other large draws? A pair of 5hp single phase compressors might be an option( you can even get two 5hp pumps on a single tank). If you don't need large amounts of air while doing other high draw operations you might even consider having an even smaller compressor to provide air but also keep the total draw down.



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[wyliesdiesels]

That entirely depends on what you're buying. I just bought a 3 phase breaker panel for $40 that listed for over $1000. And it looks brand new.

What brand and model panel??

Hopefully not a Shitsco(Zinsco) or Fire Prone Electric (FPE)...

 

[rjcnaples]

1. I would find out from your local utility provider. Can the wiring supplying(service) your residence carry the additional load? 200 amp for residence, additional 200 for garage. OR would they have to upgrade it?
You could do all this work, and still be hit with a unexpected charge.

2. At your meter location you probably have a 200amp rated socket. Your Electrican can tell you for sure.

3. If the answer to number 1 is the utility doesn’t need to change any wiring, or transformer. Then I would have a Electrican quote you the following:

A. Upgrade the meter to 400 amp size.
B. Provide (2) 200 amp disconnect means. ( 1 for house, 1 for garage)
C. Run 2” pvc with (3) 4/0AL, (1) #6 AL to garage location set a 200 amp main lug panel. ( you could save some money if you dig the ditch per instructions from the electrican possibly.

This is my advice to get you to were the internal wiring of the garage will take place. Then you will have a whole new set of questions to tackle.


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[ard]

I'm not sure yet, as they haven't mentioned any number besides if I want 400A, it would be ~25-30K because of transformers/underground/etc.

In some states/local areas, the poco is obligated to provide service for free for whatever loads you will be installing. So you may need to lay a conduit...and they may only provide X feet... but you dont pay to upgrade their equipment.

You should understand your poco regulations, rules, etc. Dont assume you will not be lied to. Telling you $30k and you go away might be perfectly fine with 'them'.

Just curious, if the MSP is 200A with breaker, and service was supposed to be as such, but the POCO sizes the service conductors for way less, isn't it a big safety hazard? Or does something trip from the POCO side first? I doubt the majority of home owners would be on top of this kind of information.

Adding on to other replies.. why would it necessarily be a safety issue? If the load calc says the home will use 90A and they wire it for 120A... AND, you are required to get a permit to change your electric wiriing, panels, loads, etc and you are required to notify POCO when a permit is pulled on an improvement that increases loads...then there is a framework that can allow them to undersize and still create some protection.

The argument that regulators and poco use it that these kinds of changes are NOT done by homeowners- that they are done by professionals, and since pros are doing it, there isnt a significant risk to the public...that a 125A servce will get changed to pulling down 300A and nobody gets told.