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cateng
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Join Date: May 2007
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Residential Service Entrance

11/26/2007 12:54 PM

I resently bought a house that has two panels coming off of one service entrance load center with a 200A breaker. There is no room for expansion in the load center. One feed goes to the house (200A panel) and one to the detached garage (100A panel). There are two problems with this: 1. One breaker feeding two panels. 2. The cable from the 200A service entrance load center to the 100A panel is sized for 100A. What is the best solution with cost in consideration? I would like to install a load center with 3 spaces. One 200A feeding the house, one 100A feeding the garage and one extra. Can I do this on the secondary side of the existing 200A load center or will I need to replace the existing 200A load center? I do not want the power company to pull the meter.
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PWSlack
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#1

Re: Residential Service Entrance

11/27/2007 4:21 AM

Why is there a perceived problem with the feed to the 100A panel?

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PWSlack
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#2

Re: Residential Service Entrance

11/27/2007 4:23 AM

Why is there a perceived problem with the feed to the 100A panel?

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cateng
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#4
In reply to #2

Re: Residential Service Entrance

11/27/2007 8:34 AM

It should be sized for 200A since a 200A breaker is between it and the service entrance.
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PWSlack
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#5
In reply to #4

Re: Residential Service Entrance

11/27/2007 8:37 AM

What's the difficulty in moving the 100A breaker upstream of the cable?

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hastingselectric
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Location: Hartwell Georgia N34* 56.770 / W83* 35.431
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#3

Re: Residential Service Entrance

11/27/2007 8:32 AM

If I understand correctly, the 200A main will protect everything. It will not allow you to pull any more amperage. Keep in mind an average home will use only a fraction of the 200A. You can't run the A/C & Heat at the same time. If your worried, put an ammeter on the entrance cables and see what you typically pull.

Good luck,

James

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North of 60
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#6

Re: Residential Service Entrance

11/27/2007 3:38 PM

What is protecting the feeders to the 100 amp panel in the garage and how long is the run?

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pwr2thepeople
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#7

Re: Residential Service Entrance

11/27/2007 3:39 PM

One breaker feeding two panels is not necessarily a problem; it depends on the inspecting jurisdiction. (Based on your comments, I assume you are somewhere in the USA).

100A wire protected by a 200A breaker is definitely a problem. We call that a fuse.

If I understand your proposal, the existing service entrance load center would not change, nor would either of the existing panels. The new 3-slot load center would be placed in series between the SE load center and the 200A house panel. You would then re-route the existing 100A cable, removing it from the SE load center & connecting it to one of the breakers in the new load center. (See attached drawings).

If the above drawings reflect your intent, the design is perfectly acceptable. It will take a dangerous situation and bring it up to code.

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hastingselectric
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#8

Re: Residential Service Entrance

11/27/2007 3:56 PM

Questions? Meter feeds the main service entrance panel? Sub-panel fed through 100A breaker in main panel? No problem, if this is the case. Add new sub-panel from main panel with appropriate breaker. Wire sized for feed breaker. No problem. If he wants to use small amperage breaker for second panel, no problem. He realizes wire must match breaker in amperage allowed. He also knows not to exceed second sub-panel rating. No 100A breaker for 60A panel. Enjoy the hot tub.

James

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cateng
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#9

Re: Residential Service Entrance

11/27/2007 10:28 PM

pwr2thepeople, you are right on with the existing setup and with what I am proposing.

Now, is it ok to mount the new load center to the back side of the SE pole, since there is no room below the existing load center, or should I mount it to a new pole? I am in KY, by the way.

Thanks
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hastingselectric
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#10
In reply to #9

Re: Residential Service Entrance

11/28/2007 6:58 AM

Mounting it to the back side of the pole looks tacky. I moved the dog house closer and mounted my on that.

James (I'm across the street)

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Users who posted comments:

cateng (2); hastingselectric (3); North of 60 (1); pwr2thepeople (1); PWSlack (3)

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