# 320 amp meter with 2-200 amp breakers



## 1joeyj

I'm looking at installing a 320 amp meter main with 2-200 amp breakers is this an acceptable method for a 400 amp single phase service? I plan to feed a new 200 amp panel in the building and an existing 200 amp MLO panel in the building from the new meter breaker combo. This is a single phase service for a sorority. Am I missing anything? Thoughts?


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## Dennis Alwon

A 320 meter base is rated 400 amps non continuous load and 320 continuous load

A 200 amp meter base is rated 200 amp noncontinuous and 160 continuous

Now why they call the 400 base 320 and the 200 amp base 200 I don't know


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## 1joeyj

I assume based on being a 320 amp continuous load then I would size the wire for 320 amps not 400 correct?


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## ElectricJoeNJ

1joeyj said:


> I assume based on being a 320 amp continuous load then I would size the wire for 320 amps not 400 correct?


What's the calculated load? Regardless of that though if it were me, id wire based on 400 amps. 500's to meter or parallel 2/0. With 2/0 on load side going to each 200 amp panel.


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## elecpatsfan

1joeyj said:


> I'm looking at installing a 320 amp meter main with 2-200 amp breakers is this an acceptable method for a 400 amp single phase service? I plan to feed a new 200 amp panel in the building and an existing 200 amp MLO panel in the building from the new meter breaker combo. This is a single phase service for a sorority. Am I missing anything? Thoughts?


 
I do my 400 amp services like this all the time, those meter/ dual main breaker packs are nice. I can't see the advantage to a 400 amp main breaker


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## HARRY304E

elecpatsfan said:


> I do my 400 amp services like this all the time, those meter/ dual main breaker packs are nice. I can't see the advantage to a 400 amp main breaker


A 400 amp main breaker then you would have to use 600's AL to your MLO's..


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## backstay

Dennis Alwon said:


> A 320 meter base is rated 400 amps non continuous load and 320 continuous load
> 
> A 200 amp meter base is rated 200 amp noncontinuous and 160 continuous
> 
> Now why they call the 400 base 320 and the 200 amp base 200 I don't know


The meter bases I get (Milibank) are 200 amp continuous rated.

SPECIFICATIONS
• Listed under UL 67 as “suitable only for use as service equipment” – file number E32628 Series 1800 MS.
• 200 amp continuous duty ringless meter socket. Accepts ANSI type C12.10 watt-hour meters. Overall ampere
rating limited to main circuit breaker rating.
• For use on 120/240 volt single phase applications.
• Short circuit withstand rating 22K AIC as standard. See wiring diagrams on back page for series rating
compatibility.
• Type 3R enclosure constructed with G90 galvanized steel.
• Light gray polyester powder coat finish.
• Service entrance overhead or underground. OH has up to 2-1/2” hub opening and UG has up to 3” knockout
• Wire terminations accept copper or aluminum conductors: Line & Neutral: # 1/0-350 kcmil Ground: #6-350
• Plug-on main circuit breaker: 60 and 100 amp type Q small frame, 150 & 200 amp type QN large frame.


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## Dennis Alwon

That's good to know. Actually I learned about the 160 on the forums and never checked. I wonder if that was a mistake or they changed them.


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## Dennis Alwon

1joeyj said:


> I assume based on being a 320 amp continuous load then I would size the wire for 320 amps not 400 correct?


I would base it on the 200 amps for each panel-- 3/0 copper


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## ElectricJoeNJ

Dennis Alwon said:


> I would base it on the 200 amps for each panel-- 3/0 copper


Why 3/0? This is a residential setting right. Wouldnt 2/0 suffice?


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## BBQ

ElectricJoeNJ said:


> Why 3/0? This is a residential setting right. Wouldnt 2/0 suffice?


Not once the load is split between two panels.


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## Dennis Alwon

ElectricJoeNJ said:


> Why 3/0? This is a residential setting right. Wouldnt 2/0 suffice?


The whole reason we are allowed to use a smaller conductor for residential is that there is a large diversity in the load. Normally you would not have a great load on the service. Once you split the load then the diversity is ruined. In reality I bet there would never be an issue but I have seen homes where the entire heating systems where all installed on one panel and the lighting and smaller loads on the other.


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