# 100A vs 200A service disconnect differences



## Black Dog (Oct 16, 2011)

jsncrso said:


> Hello all, why is it that some 100A service rated disconnects are sold with no main breaker (such as a 6 space Square D panel) but 200A disconnects always have a main? I am well aware of the 6 disconnect rule but I am just curious why this configuration is commonly on 100A panels and not 200A.
> 
> BTW, this question hit me today when I saw a 100A disconnect for a trailer have two 100A breakers (trailer/shed) and one 60A (HVAC). Obviously overloaded.


Those are sub panels, Main lug only panels.

Welcome to the forum.:thumbsup:


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## 3xdad (Jan 25, 2011)

jsncrso said:


> Hello all, why is it that some 100A service rated disconnects are sold with no main breaker (such as a 6 space Square D panel) but 200A disconnects always have a main? I am well aware of the 6 disconnect rule but I am just curious why this configuration is commonly on 100A panels and not 200A.
> 
> BTW, this question hit me today when I saw a 100A disconnect for a trailer have two 100A breakers (trailer/shed) and one 60A (HVAC). Obviously overloaded.


Welcome to ET.

Your use of terms is a little different to me. A disconnect is a breaker or a fused switch, and then there is suitable for use as service equipment such as a panel.

What you describe is not always how it is. You can get 100 and 200 panels with main breaker or just lugs, and they can still be used as service equipment as long as there is a service disconnect ahead of them.

The 6/12 space 100A can be used as service equip with 6 throws or less, but a 200 more commonly will have a larger buss and more circuit spaces.

The panel you saw may not be overloaded. It just had three service disconnects, and the calculated load may still be well under 100A.

Hope that helps.


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## Southeast Power (Jan 18, 2009)

jsncrso said:


> Hello all, why is it that some 100A service rated disconnects are sold with no main breaker (such as a 6 space Square D panel) but 200A disconnects always have a main? I am well aware of the 6 disconnect rule but I am just curious why this configuration is commonly on 100A panels and not 200A.
> 
> BTW, this question hit me today when I saw a 100A disconnect for a trailer have two 100A breakers (trailer/shed) and one 60A (HVAC). Obviously overloaded.


Typically, you can buy whatever you want main lug or main breaker.
There are also plenty of specialized loadcenters for specific applications such as the trailer panel you described.
Download a GE buy log or a Square D Digest and enjoy...


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## jsncrso (Dec 30, 2014)

Thanks for the welcome, I have been lurking quite a while.

As for my question, this 6 space panel serves as the main disconnect (as it meets the 6 breaker rule) as it's fed straight from the meter. There are many other services like this as well.

3xdad, I know you can get MLO 200 amp panels, but every one I've seen is greater than 6 spaces and would need a main beaker ahead of it. Not as easy to overload a service like that.

Anyway, the calculated load of the trailer is within limits, but it was just a curious observation I made and one I could not easily find an answer for.


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## butcher733 (Aug 4, 2012)

What makes a disconnect service rated beyond the option to bond the neutral? Do the disconnects have to be listed as service rated?


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