# 200 amp sub panel



## buffalo

I installed a new 200 amp underground service a couple years ago . It comes into the house at the opposite side of where the existing panel was . So I installed a new 200amp murray panel , then fed my existing panel with a 100 amp 3 wire and turned it into a subpanel.. All inspected .

  Now this is where I ended that project. So I never a dressed the garage and out building , which are not wired properly as they are fed with a 2 wire , and not a 3wire. I'm want to adress this now , but my first question is .....

I'd like to remove the 100 amp wire and install a 200amp line to the second panel , but I don't see a 200amp breaker available . (Then I'll re use the 100 amp line for the garage ) . What's the  proper way to feed 200amps from a main panel to a 200amp sub panel ?


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## nealtw

Would be better to go all the way to the new panel for 100 amps.


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## buffalo

nealtw said:


> Would be better to go all the way to the new panel for 100 amps.



The run would be twice as long then . Plus the main panel only has one 15 amp breaker being used , all my electric comes off the second panel , so I have a 200amp service with 100 amp limit.


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## beachguy005

I believe you would use 200 amp sub feed lugs in your main panel to feed the second panel, but is the second panel rated at 200 amps, and does it have a main breaker?


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## nealtw

beachguy005 said:


> I believe you would use 200 amp sub feed lugs in your main panel to feed the second panel, but is the second panel rated at 200 amps, and does it have a main breaker?



Then the cable has to be rated for 400 amps all the way to the transformer.


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## beachguy005

His new panel was 200 amp, I'm figuring that it's a main breaker panel.  He's never going to draw more than that main.


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## buffalo

beachguy005 said:


> I believe you would use 200 amp sub feed lugs in your main panel to feed the second panel, but is the second panel rated at 200 amps, and does it have a main breaker?




Yes this is what I am looking for , thanks !

It's rated at 200 amps and yes , it has a main breaker also .


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## buffalo

buffalo said:


> Yes this is what I am looking for , thanks !
> 
> It's rated at 200 amps and yes , it has a main breaker also .



Would this leave the new wire unprotected?


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## beachguy005

No because of the main breaker and as long as the wiring is properly sized.  I would also suggest that you do a sketch of your new wiring plan and run it by a licensed electrician and or your electrical inspector as your local laws may require.


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## afjes_2016

buffalo said:


> ...So I installed a new 200amp murray panel , then fed my existing panel with a 100 amp 3 wire and turned it into a subpanel.. All inspected ...



Sorry for being a "Sunday Quarterback" here but did you feed your existing panel (which is now your sub panel) with a SER 3 wire plus ground from the new Murray panel? There should be a total of 4 wires going to the sub panel. The existing panel being turned into a sub panel should have had the ground and neutrals separated (since when it was the existing main panel the ground and neutral would have been bonded together). Are we assuming this is what was done? If it was then fine. If it was only a 3 wire (total) and was inspected; wondering now.


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## buffalo

afjes_2016 said:


> Sorry for being a "Sunday Quarterback" here but did you feed your existing panel (which is now your sub panel) with a SER 3 wire plus ground from the new Murray panel? There should be a total of 4 wires going to the sub panel. The existing panel being turned into a sub panel should have had the ground and neutrals separated (since when it was the existing main panel the ground and neutral would have been bonded together). Are we assuming this is what was done? If it was then fine. If it was only a 3 wire (total) and was inspected; wondering now.



It was done with 4 total wires , but 100 amp wire and breaker . I redid the entire house so yes grounds and neutals seperate .


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## afjes_2016

buffalo said:


> It was done with 4 total wires , but 100 amp wire and breaker . I redid the entire house so yes grounds and neutals seperate .



Ok, good. Just wanted to be sure. Nice job.


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## hornetd

nealtw said:


> Then the cable has to be rated for 400 amps all the way to the transformer.



That is not true.  If sub feed lugs are used the connections for the cable to the older panel; which is now a feeder supplied panel; would be on the main buss bars of the new panel.  The feeder would be protected by The Main Breaker of the New Panel.  Just remember that the cable to the older panel must be Four Conductor.  Make sure that you have removed the Main Bonding Jumper in the original panel and have separated the Neutrals and the Equipment Grounding Conductors onto separate buss bars.  The buss bar you use for the neutrals must be isolated from ground everywhere except in the new panel which is now your Service Equipment.


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## nealtw

hornetd said:


> That is not true.  If sub feed lugs are used the connections for the cable to the older panel; which is now a feeder supplied panel; would be on the main buss bars of the new panel.  The feeder would be protected by The Main Breaker of the New Panel.  Just remember that the cable to the older panel must be Four Conductor.  Make sure that you have removed the Main Bonding Jumper in the original panel and have separated the Neutrals and the Equipment Grounding Conductors onto separate buss bars.  The buss bar you use for the neutrals must be isolated from ground everywhere except in the new panel which is now your Service Equipment.



Yes, beachguy pointed that out.

But it does sound like a little expensive for little gain if any.


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## hornetd

nealtw said:


> Yes, beachguy pointed that out.
> 
> But it does sound like a little expensive for little gain if any.


As I understand his question he has outbuildings on the side of his house were his Original panel is located.  That panel is supplied by a 100 ampere feeder.  He wants to add some loads into that panel but he is concerned he may overload the 100 ampere feeder.  To avoid that possibility he will have to run a feeder or feeders back to the Service Equipment Enclosure.  I would think that he is better off making the entire 200 Ampere capacity of his service available to the panel were all his present loads are.  That does eliminate the possibility that he will overload the Feeder to the original panel either now or in the future.  Since he will have to do the work of running a feeder back to the Service Equipment he might as well make it a 200 Ampere feeder so he can save having to do another extra long run later.  That sounds like a rational plan to me.  What am I missing?


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## nealtw

He has a new supply and a cable going to the old panel in the house.
He has old cable from old panel to garage that needs to be replaced.
He is going to selvage the cable in the house and run that from the old panel to the garage.
Buy a bigger cable and run that between the new box and old box in the house.
and buy an expensive 200 amp breaker.

Or one new cable from the garage to the new box and a new 100 amp breaker.

I am not sure what I am missing.


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## hornetd

nealtw said:


> He has a new supply and a cable going to the old panel in the house.
> He has old cable from old panel to garage that needs to be replaced.
> He is going to selvage the cable in the house and run that from the old panel to the garage.
> Buy a bigger cable and run that between the new box and old box in the house.
> and buy an expensive 200 amp breaker.
> 
> Or one new cable from the garage to the new box and a new 100 amp breaker.
> 
> I am not sure what I am missing.


OK!  Now I think I follow you.  He already changed the feeder to the existing panel to four wire?  How much difference is that going to make in the length of other feeders added later on?  How much additional work will be involved in running the feeders to the new service equipment?  

If the garage is the only issue you are correct. but he mentioned a garage and an outbuilding.  If he anticipates any additional feeders from the side of the house were the old panel is he may well be better off biting the bullet now by changing out the feeder to the old panel to the larger size.  If he uses a sub lug kit in the new panel then he does not have to buy another breaker.  The Feeder and both 200 ampere panels will be protected by the main breaker of the new Service Equipment panel.  The main breaker in the older panel becomes superfluous but since he said it is 200 Amperes it does no harm.


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## afjes_2016

hornetd do you realize you are replying to this thread that is almost one year old now?

But thank you for your opinion based on your 50 years experience in the field. It is much appreciated!!


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## nealtw

I think he finished it, but he was also checking with inspectors as he went , this was just kicking ideas around.
Keep in mind this was about not spending any more money, as this was after replacing the top floor of the house and the roof of that house and the roof over the suite on the side. In the middle of that he lost half the garage to frost heave. The panel upgrade was so he could run new under ground to get power out of the way for the construction upstairs.


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## hornetd

afjes_2016 said:


> hornetd do you realize you are replying to this thread that is almost one year old now?
> 
> But thank you for your opinion based on your 50 years experience in the field. It is much appreciated!!


Whoa!  I didn't look at the dates; obviously.  Now I want to figure out how a notification about this thread could show up in my in box so many months late.  If I hear Rod Sterling in the background I'm gonna seriously freak.


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## afjes_2016

hornetd said:


> Whoa!  I didn't look at the dates; obviously.  Now I want to figure out how a notification about this thread could show up in my in box so many months late.  If I hear Rod Sterling in the background I'm gonna seriously freak.



That's quite ok nornetd.   We do appreciate someone with your "season" contributing to our conversations. It brings "light" and we get to learn more from ones like you that have been in the field for so much longer than us. Thank you for your help! This way when someone in the future does a search on a topic they will find useful information to guide them.

As far as why you just got notification of the post; well I will leave that to a moderator.



> If I hear Rod Sterling in the background I'm gonna seriously freak.



That's great!!  I am about 62 now so I remember those great evening programs with Rod; gotta love them!!


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## WyrTwister

buffalo said:


> I installed a new 200 amp underground service a couple years ago . It comes into the house at the opposite side of where the existing panel was . So I installed a new 200amp murray panel , then fed my existing panel with a 100 amp 3 wire and turned it into a subpanel.. All inspected .
> 
> Now this is where I ended that project. So I never a dressed the garage and out building , which are not wired properly as they are fed with a 2 wire , and not a 3wire. I'm want to adress this now , but my first question is .....
> 
> I'd like to remove the 100 amp wire and install a 200amp line to the second panel , but I don't see a 200amp breaker available . (Then I'll re use the 100 amp line for the garage ) . What's the  proper way to feed 200amps from a main panel to a 200amp sub panel ?



     The cable going to the sub panel must contain 3 insulated wire plus an earth ground , which may be insulated ( green ) or bare .

     Why do you wish to increase this sub panel from 100 amp to 200 amp ?  Have you tripped the 100 amp Circuit Breaker feeding it ?  Haveyou ever tripped the 100 amp CB ?  Are you planning on adding substantial load to the sub panel .

Wyr
God bless


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