Existing 200A/200A Split Main Breaker Panel

[broncokrawler]

I am planning on wiring a sub panel for my 40x60 detached garage. On my house, I have a 200A/200A Split Main Breaker Panel with 3/0 AWG wire feeding the split main breakers. The 2nd breaker is unused. How do I determine what capacity sub panel I will be able to install?

Thanks,

Brent

 

[wyliesdiesels]

Need more details.

What loads do u have in the house?

What loads will u havenin the garage?

One man shop 2 man shop??

How long is the wire run?

 

[broncokrawler]

The design load for the house from the electrical schematic shows 157 amps.

2 a/c 70a, range 50a, refrig 20a, dryer 40a, washer 20a, water heater 30a, dishwasher 20a

The garage will have 2 post lift 30a, welder 40a, plasma 30a, compressor 30a,

Mainly one man shop, with the exception of a buddy running the lift while I am working on something else.

The wire run is approx 80 ft

 

[wyliesdiesels]

Ok what about the house??

 

[broncokrawler]

I edited the last post with house loads.

 

[wyliesdiesels]

Dryer would be 30a.

Are the loads u listed breaker sizes?

 

[broncokrawler]

I added a pic of the main bkr panel, design loads, and single line diagram.

 

[broncokrawler]

Yes, they are bkr sizes

 

[wyliesdiesels]

Someone goofed on the dryer circuit which would be 30a with 3 #10s NOT #6s but the VA on the right is about right.

Considering someone goofed on that, i would do my own load calc to check for accurracy.

If u come up with the same, then running a compressor and plasma cutter as well as lift at the same time as many of those loads in the house are on you may have an issue especially with the in rush current of the compressor motor when starting as well as the air conditioner motors.

Do a load calc for the shop as well. Any heat or AC? Water heater??

And this house is 4,000 sq ft??

Yeah u may need to upgrade to 400/320.

Load calcs will tell u for sure.

 

[ard]

How about this question:

Given the hardware ALREADY INSTALLED. Including the house loads, what is the largest service he could wire (main breaker and subpanel) and what loads could he plan for the shop, given those "restrictions".

 

[broncokrawler]

No heat/ac/water heater in garage, I will probably just use a portable swamp cooler for awhile.

The house is 2850 sq ft, being in phx area running a/c throughout the summer is on all of the time.

Since the main breaker is split, and the supply is from 3/0 wire, am I constrained to about 225 a max for both breakers due to wire size?

I will work on a load calculation for house and garage.

Thanks,

Brent

 

[broncokrawler]

I made up a spreadsheet of the loads.

Given the split breaker design, is it feasable to have a 125 amp sub panel for the garage?

What do you recommend?

 

[wyliesdiesels]

cant read that. resolution too low.

 

[broncokrawler]

Sorry about that, not used to keeping docs so small.

 

[broncokrawler]

I updated the load sheets, I made a few mistakes. It is really hard to keep under the upload file size!

 

[ToddW]

I wish my panel was setup like that

 

[ard]

I am planning on wiring a sub panel for my 40x60 detached garage. On my house, I have a 200A/200A Split Main Breaker Panel with 3/0 AWG wire feeding the split main breakers.

What 3/0 are you referencing?

If it is 3/0 from the meter base to the 200A bus, I believe that is from the factory- hence it was UL listed for 400A as built.

(I have a similar panel- 400A w twin 200A mains. Square D. The residence is on a 200A sub fed by the 2nd breaker. Barn, Shop, Pool and outdoor circuits are on the integrated panel.)

What is the mfg and part number for the panel?

If you are talking about the wire feeding from the pole onto the property, that is a poco issue.

 

[wyliesdiesels]

What 3/0 are you referencing?

If it is 3/0 from the meter base to the 200A bus, I believe that is from the factory- hence it was UL listed for 400A as built.


What is the mfg and part number for the panel?

If you are talking about the wire feeding from the pole onto the property, that is a poco issue.

Where are u getting that 3/0 cu is large enough for 400a??

No where near close.

For service entrance feeding a dwelling, 310.15(b)(7) says 400Kcmil is required for 400a.

If not for a dwelling 600Kcmil would be required.

 

[broncokrawler]

The 3/0 from meter to the split 200a breakers.

It is a Cutler Hammer HP4040

I was just questioning feeding 2 200amp breakers with 3/0, since it is not rated for 400 amps, as far as I can tell.

 

[broncokrawler]

So how do I calculate what size subpanel could be used given the actual loads I had listed?

 

[wyliesdiesels]

Yes 3/0 is too small for 400a.

Are u sure its 3/0 cu??

Im still trying to figure out what size service u have. I cant answer the load question until we know this.

Is the HP4040 the entire panel model number??

 

[wyliesdiesels]

Well i found similar panel model numbers such as HP404040SH...

And that does look like the typical size of a 400a main service panel.

I just find it hard to believe that the wire feeding the 2 main breakers is 3/0 cu which is way too small.

 

[wyliesdiesels]

Sorry about that, not used to keeping docs so small.

I updated the load sheets, I made a few mistakes. It is really hard to keep under the upload file size!

Why is the microwave on the same line as the oven??

Microwave is 120v oven is 240v.

And a moot point dryer circuit is 3 #10s not 3 #6.

 

[gooseberry1]

HP404040shf from Eaton


Sent from my iPad using Tapatalk

 

[ard]

Yes 3/0 is too small for 400a.

Are u sure its 3/0 cu??

Im still trying to figure out what size service u have. I cant answer the load question until we know this.

Is the HP4040 the entire panel model number??

Respectfully, you need to make sure that statement is accurate.

The wire size Eaton uses for that internal jumper, that has passed UL testing, may be fine. Look here: http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/vol01_tab04.pdf

Page 79 HP404040SHF

"Factory installed"

As I posted, we don't know what the POCO has installed TO the meter base, but internal to the panel it appears UL and the listing agencies do not have to use the Code to determine wire sizing. (I.e. From the meter base to the twin 200Amp switches.)

3/0 CU may be fine for the 18 inch run for "320 Amp Continuous"

 

[ard]

The 3/0 from meter to the split 200a breakers.

It is a Cutler Hammer HP4040

I was just questioning feeding 2 200amp breakers with 3/0, since it is not rated for 400 amps, as far as I can tell.

Call Eaton/Cutler Hammer consumer affairs and ask them...THEY are the ones that sold it and installed that wire/breakers.

 

[wyliesdiesels]

Respectfully, you need to make sure that statement is accurate.

The wire size Eaton uses for that internal jumper, that has passed UL testing, may be fine. Look here: http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/vol01_tab04.pdf

Page 79 HP404040SHF

"Factory installed"

As I posted, we don't know what the POCO has installed TO the meter base, but internal to the panel it appears UL and the listing agencies do not have to use the Code to determine wire sizing. (I.e. From the meter base to the twin 200Amp switches.)

3/0 CU may be fine for the 18 inch run for "320 Amp Continuous"

I was speaking in general ampacities. I didnt have the panel details so i wasnt speaking spcific to the panel other than the apparent wire size.

And i mustve missed something. Where does it say the wire size on pg 79?

Call Eaton/Cutler Hammer consumer affairs and ask them...THEY are the ones that sold it and installed that wire/breakers.

Well not so fast. we dont know if everything in the panel is original.

 

[broncokrawler]

Sorry, the full panel part# is HP404040SH. The wire has 3/0 on the jacket and its copper stranded wire. You can see it in the picture from one of the earlier posts.

The microwave and oven are combined, and I got the amp rating from the manual of the unit online.

 

[ard]

I was speaking in general ampacities. I didnt have the panel details so i wasnt speaking spcific to the panel other than the apparent wire size.

And i mustve missed something. Where does it say the wire size on pg 79?

Well not so fast. we dont know if everything in the panel is original.

I think we are getting there...



The reference to page 79 was to show that that panel comes configured with two 200A breakers, and is rated to 320A continuous....

You are correct, someone could have messed with it- hence the call to Eaton,

I know the OP wants a solution, and frankly my expertise with the code in this area is thin- so I am not making any pronouncements. I could say "what Id do", and I would bet his county would sign off on it and be done (200A sub controlled by th3 factory installed 200A switch in his panel. Done. IMO this would be 'safe' and would be within the specs of the panelboard. Dont know if code allows this. He has put together load calcs, so I home someone can give a better answer.)

I have asked I think twice about where this 3/0 wire" actually is- is this internal to the panelboard, from meter base to breaker bus? Or is this the service TO the meter from the POCO? From the OPs ast post, I am assuming this is internal- hence this is absolutely a question for Eaton- is this 'factory'? At 3/0 what is the allowable ampacies? 200+200?


Slow day, maybe ill call eaton...

 

[ard]

Eaton tech support states:

3/0 is the wire size from the factory.

Unit is listed using that size, will handle 400A/320A continuous.

Eaton provided a document on the 3/0 wire used and states "Wire rated at 392 amps...passed U.L. heat rise test, wire is fine stranded for increased ampacity & flexibility."

So, IMO, the 3/0 wire provided by Eaton in mfg is adequate to power the dual 200A breakers.

 

[wyliesdiesels]

Well assuming the 3/0 wire is factory installed, the next question is whether he has 400/320 service as far as the meter, service lateral wire is concerned...

OP should call the PoCo.

If he does have 400a service then hes good to go.

If its only 200a then hes pushing it but if he manages his loads he could get by.

 

[wyliesdiesels]

Eaton tech support states:

3/0 is the wire size from the factory.

Unit is listed using that size, will handle 400A/320A continuous.

Eaton provided a document on the 3/0 wire used and states "Wire rated at 392 amps...passed U.L. heat rise test, wire is fine stranded for increased ampacity & flexibility."

So, IMO, the 3/0 wire provided by Eaton in mfg is adequate to power the dual 200A breakers.

My phone didnt show your latest comment when i typed my last comment.

And so the wire is different than standard building wire.

Makes sense...

OP can u take a pic of the meter up close.

Im wondering what your meter is rated at.

Its probably CL400 but since weve already gone this far one last thing wont hurt.

 

[broncokrawler]

So I pulled off the left side of the breaker panel and the Poco incoming feeders are 4/0 aluminum, and the meter has CL200 on the faceplate.

Will I be responsible for the cost to have this upgraded for higher amperage from the Poco?

Any recommendations?

Thanks for the help, it is a bit on the grey side.

 

[ToddW]

They wanted 15k$ to upgrade me to 400A !

 

[broncokrawler]

Ouch, I didnt want to hear that!

 

[ard]

Todd- $15k for the poco to run 40 feet of wire to your meter??

Or from the contractor to install a 400A panel, retrench for 3" conduit and run wire??

The point is that a number without scope isnt much help to OP

Brent- not sure you said where you are, but with your calcs you are ready to talk to the poco. Your mindset should be "I am trying to buy MORE of your product and make is EASIER for you to make money."

 

[wyliesdiesels]

FYI youre not suppose to open that section. Did it have a meter seal tag on it?

Your meter pic is blurry but ill take your word for it.

Next step call PoCo.

As far as their wire sizes go, they have different rules and ampacities.

But the meter is only a 200a meter so that at least needs to be changed.

Does your PoCo have a "blue book" (utility service requirements and regs) available online??

 

[ToddW]

Todd- $15k for the poco to run 40 feet of wire to your meter??

Or from the contractor to install a 400A panel, retrench for 3" conduit and run wire??

The point is that a number without scope isnt much help to OP

Brent- not sure you said where you are, but with your calcs you are ready to talk to the poco. Your mindset should be "I am trying to buy MORE of your product and make is EASIER for you to make money."

Putting words in my mouth? Not sure where you pulled 40' from but I have my own pole for an aerial run of maybe 200' from the street which has my own transformer, and from the pole on my property it's another couple hundred feet to my meter under ground.

This was their 'estimate' starting point, but I've talked to others with the 50' run who did 400A (and transformer) and it ended up being right around 15k$ for their installs as well.

I've talked to others not in my area and it was thousands upon thousands to get 400A from power company. Maybe it's a California thing? But it's not cheap, and they really don't want to do it!

I'm looking into how to get a 2nd address to get another 200A pull and another meter as that's probably cheaper!!

 

[ard]

Putting words in my mouth? Not sure where you pulled 40' from but I have my own pole for an aerial run of maybe 200' from the street which has my own transformer, and from the pole on my property it's another couple hundred feet to my meter under ground.

This was their 'estimate' starting point, but I've talked to others with the 50' run who did 400A (and transformer) and it ended up being right around 15k$ for their installs as well.

I've talked to others not in my area and it was thousands upon thousands to get 400A from power company. Maybe it's a California thing? But it's not cheap, and they really don't want to do it!

I'm looking into how to get a 2nd address to get another 200A pull and another meter as that's probably cheaper!!

I was being a bit of a snark, so I apologize for that. I try not to do that on GJ...

My point, and your details confirm- is that the $$ estimate is driven by the circumstances. Sounds like you have aerial, then underground, 400 ft total feet, a transformer upgrade too? Brent may have a far simpler path, and may not have the same poco, so we will see.

(PG&E here...sure has changed over the years)

 

[wyliesdiesels]

Putting words in my mouth? Not sure where you pulled 40' from but I have my own pole for an aerial run of maybe 200' from the street which has my own transformer, and from the pole on my property it's another couple hundred feet to my meter under ground.

This was their 'estimate' starting point, but I've talked to others with the 50' run who did 400A (and transformer) and it ended up being right around 15k$ for their installs as well.

I've talked to others not in my area and it was thousands upon thousands to get 400A from power company. Maybe it's a California thing? But it's not cheap, and they really don't want to do it!

I'm looking into how to get a 2nd address to get another 200A pull and another meter as that's probably cheaper!!

As pointed out by ARD above, the length of the overhead and underground service lateral and the 400a dictates VERY large wire to combat voltage drop. Plus PoCo most likely would need to retrench and lay new pipe.

But perhaps instead they wouldve ran high voltage primary over or under that 400' then set a pad mount transformer which would get rid of the voltage drop problem over that distance.

The $15k quoted seems more likely to be for a pad mount transformer...

Who is your PoCo? PG&E?