200 amp service with 400 mcm

[james cohee]

thanks for all the input fellas. designing for voltage drop is primary concern as a pv install is planned in the future. as they are only 20% efficient at best every watt counts. i would love to use transformers to make the job easier but my understanding is that they use 300-400 watts 24-7 365. the thought of having pv to power transformers is not so appealing. so it appears we will be stuck wrestling with this monster wire. the reason we problobly will not go with al is bcause it is near the coast and the salt air is harsh on the al. it is a fairly straight run but it appears i will need to hire out the actual pull to someone with a pullin rig. ??? with efficiency in mind, should i go from property line meter to garage panel, from garage panel to house. or from property line meter to house with a loop by the planned garage that we could tap into later when garage is built. generator will be by garage panel. ps 400 amp service is not an option w/o a lengthy fight.

 

[james cohee]

thanks for all the input fellas

thanks for all the input fellas

thanks for al the input. voltage drop is of great concern as a pv install is planned in the future. as they are only 20% efficient at best the thought of installing pv to power transformers is not very appealing. my understanding is that they consume 300- 400 watts 24-7-365. if i could find transformers that were more efficient than monster wire i would be allover it. who wants to wrestle with 400 mcm along with having to hire out a pullin rig. ?? with efficiency as top concern should i go from property line panel to garage panel, then to house or prop. line panel to house with a loop near planned garage that i could tap into at a later date.
ps 400 amp service not an option

 

[nate roach]

I'd just get a big wood burning generator.


Frank, I can tell already that your one hell of a guy! clever, but not very efficent.. we wanna keep the trees not burn them.. thanks though!!

 

[ultramegabob]

what is the issue with the power company and you installing a 400 amp meter base? I just dont get why they care, your load is going to be the same no matter what size your meter base is.

 

[Buck Parrish]

Nate, did you do a load calculation. Then do a voltage drop calculation.
I think the reason you are getting so much hype. Is the 400 mcm cu. sounds like a over kill for the 200 amp service that you want to install.
Even with a voltage drop.

From your statement it sounds like your
area poco provides a disconnect at the property line? Probably the meter may be on the property line to.

If your garage is in the middle of the route to the house. And it is to be built in the future. Perhaps you could put a temp pole with panel their. Then down size the wire. #2 cu should be more then enough to cover any voltage drop for the 100 amp service to the house

 

[Smart $]

...who wants to wrestle with 400 mcm along with having to hire out a pullin rig. ??

So why not direct burial?

...with efficiency as top concern should i go from property line panel to garage panel, then to house or prop. line panel to house with a loop near planned garage that i could tap into at a later date.
ps 400 amp service not an option

Your OP says 250' to garage and another 250' from there to house, but you never mentioned whether that was in a straight line away from the service point. For all we know the three form a big equilateral triangle and the house is also 250' from the service point.

If service point-garage-house route is fairly straight, I'd make provisions for tap to garage later when it is built or in the process thereof.

 

[Buck Parrish]

Mount a 200 amp feed through breaker panel where the garage will be in the future. Mount a box under it and use the terminations Iwire described in an earlier thread. Use 2- 6x6's to mount the box on, make it permanent if you want

If you total load averages 170 amps at 240 volts
400 kcmil being used you would drop 2.7 volts at the 250' mark
and 5.3 volts at the 500' mark

It would be safe to say use 400 cu kcmil to the garage from their If the house load averages 70 amps
2/0 copper at 250 feet only drop 1.8 volts.

That's only about 3% drop which is acceptable.
If you want to be extra safe use 3/0 cu to the house.

These figures are at 240 volts nominal. Some times you may have up to 243 volts coming off the poco's transformer. This would make it almost perfect.

 

[james cohee]

thanks smart $. great idea with the direct burial. i'm going to check with the county tomorrow.

 

[Buck Parrish]

thanks smart $. great idea with the direct burial. i'm going to check with the county tomorrow.

That only comes in Aluminum

 

[Smart $]

That only comes in Aluminum

au contraire, monsieur... http://www.okonite.com/Product_Catalog/section3/sheet9.html

Of course I understand your comment likely made no consideration for industrial type cable.

 

[Smart $]

...
If you total load averages 170 amps at 240 volts
400 kcmil being used you would drop 2.7 volts at the 250' mark
and 5.3 volts at the 500' mark

It would be safe to say use 400 cu kcmil to the garage from their If the house load averages 70 amps
2/0 copper at 250 feet only drop 1.8 volts.
...

With the same loads being served, per 250' leg, changing from 4/0 to 2/0 is NOT going to lower the VD for the second leg of the run

Rethink your calculation.

 

[james cohee]

thanks for the link smart money. great product but at 37$ a foot for 350 mcm it is a bit cost prohibitive. looks like i'll have to go with 600 al direct burial. does anybody make a similar product for al? thanks.

 

[Smart $]

does anybody make a similar product for al? thanks.

http://www.southwire.com/Southwire/StaticFiles/Text/armorliteAlumaflexPVC.pdf

 

[K8MHZ]

Bob, you answered his question in the 2nd post, I dont see the problem in offering an easier solution to his question... IMO, there is no efficient way to connect 400 mcm to 200 amp panel and breakers. Not in the residential world anyway.

I didn't read every response, but.....

In power houses they routinely oversize conductors. To connect them to a terminal that would not accept the larger wire we used 'pin adapters'. I don't know where the EC got them, they may have been supplied by the power company, but they will work but are a real pain to use, especially in cold weather where you have to try to get 400's to fit in a panel not meant for them. 400's are like bar stock when the temp gets below 20 or so.