# Using 200 amp disconnect on 125 amp feeder?



## McClary’s Electrical (Feb 21, 2009)

nitro71 said:


> I'm pretty burnt out at the moment, it was hot today. I can use a 200 amp main breaker on a detached garage with a 125 amp fused feeder can't I? The 200 just acts as a short, ground and disconnect while the 125 protects the wire. There isn't a problem with this is there?


 


fuses at the house? 200 in garage? if so,,,,you're fine. If the other way around, you're not fine.


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## nitro71 (Sep 17, 2009)

That's what I thought. Thanks for the heads up. I'm beat but needed to double check.


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## kbsparky (Sep 20, 2007)

mcclary's electrical said:


> fuses at the house? 200 in garage? if so,,,,you're fine. If the other way around, you're not fine.


Tap conductor rules may apply here. No limit to the length if the feeder is outside. 

Inside feeders may be limited in length to 25 feet, however.


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## nitro71 (Sep 17, 2009)

Tap rules shouldn't apply here. The 125 amp breaker, protected, feeder goes to the detached garage that has a 200 amp main. Good to go, right.


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## Bob Badger (Apr 19, 2009)

nitro71 said:


> Tap rules shouldn't apply here. The 125 amp breaker, protected, feeder goes to the detached garage that has a 200 amp main. Good to go, right.


From what you have told us I would say good to go.


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## nitro71 (Sep 17, 2009)

I wouldn't plan it like this but I'm building off of some available materials. Like to dot my i's and cross my t's.


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## Shorty Circuit (Jun 26, 2010)

nitro71 said:


> I'm pretty burnt out at the moment, it was hot today. I can use a 200 amp main breaker on a detached garage with a 125 amp fused feeder can't I? The 200 just acts as a short, ground and disconnect while the 125 protects the wire. There isn't a problem with this is there?


As I understand you, the feeder upstream is fused at 125 amps and the main breaker on the garage panel is 200 amps. Since the feeder is protected at 125 amps, that is OK IMO. The 200 amp breaker is simply being used as a disconnect, not to limit ampacity. I assume the feeder is rated at 125 amps (#2) or can be construed to be by using the tap rule if it applies.

If it is not, you might get away with it and get it past the insepctor anyway by painting the rating on the breaker handle. I'd gusss glossy black would be the best color to hide the 200 amp rating. Just don't get it on anything else or it might arouse suspicion.


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## nitro71 (Sep 17, 2009)

I'm not trying to slide anything dodgy by the inspector. No painting will be done! Got my marbles back today. It was hot yesterday.


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## wildleg (Apr 12, 2009)

Shorty Circuit said:


> If it is not, you might get away with it and get it past the insepctor anyway by painting the rating on the breaker handle. I'd gusss glossy black would be the best color to hide the 200 amp rating. Just don't get it on anything else or it might arouse suspicion.


I have a better idea. don't ever, ever do what this poster suggested.


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## MDShunk (Jan 7, 2007)

It's always okay to use a switch or disconnect that is more "heavy duty" than what you really need, as long as your overcurrent protection is already squared away. What you describe is functionally no different than using a 30 amp manual motor starter to switch your 15 amp fed hallway light in your house. Overkill, but nothing expressly wrong about it.


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## oldtimer (Jun 10, 2010)

nitro71 said:


> Tap rules shouldn't apply here. The 125 amp breaker, protected, feeder goes to the detached garage that has a 200 amp main. Good to go, right.


 I don't think you can purchase a 125 amp, or 150 amp rated disconnect. I believe it is 30 - 60 - 100 - 200 - 400 - etc. I may be wrong! 

Circuit Breakers ... ... a variety of amperage ratings.


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## Shorty Circuit (Jun 26, 2010)

From the initial posting I infer he's referring to 125 amp fuses upstream, not to the rating of the disconnect itself.


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## MDShunk (Jan 7, 2007)

Shorty Circuit said:


> From the initial posting I infer he's referring to 125 amp fuses upstream, not to the rating of the disconnect itself.


I think what he was saying is that you couldn't even buy a 125 amp disco, even if you wanted to, and you're stuck with the 200. I don't think that's completely true though, but I think that this was his point.


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## Shorty Circuit (Jun 26, 2010)

MDShunk said:


> I think what he was saying is that you couldn't even buy a 125 amp disco, even if you wanted to, and you're stuck with the 200. I don't think that's completely true though, but I think that this was his point.


I've never seen a 125 amp rated fused disconnect switch that would only accept a 125 amp fuse and no larger. That's not a standard size. You'd obviously need to buy a larger switch and fuse it at 125 amps. But there are 125 amp circuit breakers which do the same thing. Sheesh.


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## nitro71 (Sep 17, 2009)

I just meant fused meaning protected. Pretty sure you can get a 125 amp QO breaker.


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## Schultz134 (Jul 25, 2010)

Why not just use a main lug panel in the garage and skip the 2nd breaker/diconnect all together?


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## MDShunk (Jan 7, 2007)

Schultz134 said:


> Why not just use a main lug panel in the garage and skip the 2nd breaker/diconnect all together?


There's this funny little thing called the NEC.


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## jwjrw (Jan 14, 2010)

Schultz134 said:


> Why not just use a main lug panel in the garage and skip the 2nd breaker/diconnect all together?


 
Hope you plan on putting a main breaker and a tie down in that main lug panel........:whistling2:


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## Schultz134 (Jul 25, 2010)

Can't find it in the NEC. Where does it say you need a 2nd disconnecting means?


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## MDShunk (Jan 7, 2007)

Schultz134 said:


> Can't find it in the NEC. Where does it say you need a 2nd disconnecting means?


I'm sure it's in art 225 somewhere. It's definitely there, though.


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## Schultz134 (Jul 25, 2010)

I will investigate further. But I thought it was a common misconception that you need 2 means of Protection/disconnect


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## jwjrw (Jan 14, 2010)

Schultz134 said:


> I will investigate further. But I thought it was a common misconception that you need 2 means of Protection/disconnect


 

Each building needs its own disconnect.


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## nitro71 (Sep 17, 2009)

And the main panel was already in place. So you run what the customer brung.

We decided a 100 amp feeder was sufficient instead of the 125. Saved him about $300 or so.


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