Load off Main panel

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  #1  
Old 10-12-12, 01:09 AM
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Question Load off Main panel

If you have a main load center off the meter, that I beleive is a 100 amp lug load center. But has a double pole 100 amp breaker thats back feed onto the main bus from the meter.
and then the main lugs are used to run straight to a 100 amp sub panel which would be the main panel inside the mobile. there is also a double pole 30 amp breaker that goes to a cut off for central air unit.
Can you still add another 60 amp sub panel off that main panel ?

at ths point, I'm not sure what amount of juice is coming to the meter.
[under ground lines]
 
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Old 10-12-12, 01:23 AM
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Where the service comes in is the main panel. That was someones' creative idea to convert a 100amp main lug sub panel into a 100amp main breaker panel. You can add another 60amp sub panel but remember you only have a 100amp service so you can't exceed that in current demand.

You know there is at least 100 amps coming to your service.

With an aerial drop it's common when upgrading from a 100amp service to a 200amp for the power company to still use the same service drop cable. This is called "free air". An underground service is a little different, larger wire may have to be pulled to increase service size..
 
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Old 10-12-12, 08:11 AM
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Yup, you can add the 60A sub panel, but as PJmax mentioned, you're still limited by the 100A main feed.

You may want to do a "demand load calculation" (Google has links to some online calculators) if you're planning on adding any significant power draw to determine whether the 100A feed will be sufficient. If you're just looking for a few extra receptacles and lights, you should be good to go.
 
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Old 10-12-12, 11:28 AM
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follow up question

ok I follow; if the main breaker doesn't keep tripping. no worries....

follow up question:
but,.... if.....

The main box is outdoor 125 amp rating GE. the lines coming from the meter are #2 awg alum.
If I find, that as you guys say, I'm drawing a little too much with the new 60 sub panel and the main panel breaker keeps tripping, can the #2 alum. wire handle an upgrade to 125 amp breaker; replacing the 100 amp there now that might be all I'll need to get by.

-------------------
hum? what size alum. awg for a 200 amp main feed from meter to main box?

or would copper be needed/better?
It's only about a 2' run of wire that would be needed. (three- 2' wires)
 
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Old 10-12-12, 04:01 PM
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the lines coming from the meter are #2 awg alum.
If I find, that as you guys say, I'm drawing a little too much with the new 60 sub panel and the main panel breaker keeps tripping, can the #2 alum. wire handle an upgrade to 125 amp
Aluminum THWN #2 is rated for 100 amps max at 90C.
 
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Old 10-12-12, 04:06 PM
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And #2 copper THWN is rated for 130 amps.
 
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Old 10-12-12, 04:11 PM
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Typically other components to be upgraded besides the wires between the meter and panel. It is not just installing a larger breaker.
 
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Old 10-12-12, 06:48 PM
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what size alum. awg for a 200 amp main feed from meter to main box?
For residential service, 2/0 copper THWN or 4/0 aluminum THWN or XHHW is needed for 200 amp service. In addition, a 200 amp meter socket is required. If the underground feeder is privately owned, the typical service upgrade also includes upgrading the underground feeder to 4/0 aluminum. If the underground feeder is utility company owned, the utility company would decide whether to upgrade it usually based on load. They possibly would also decide whether to charge you for the upgrade depending on load and payback. Contact your power company for their exact policy.
 
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