400 amp residential service

[kolega]

i have a 400 amp service on the side of the house with 2 200 amp disconnects. i need to run power from one of those disconnects to detached shop which is about 175 feet away can i use direct burial wire?

 

[kwired]

Why do you think you couldn't use it?

It does need to be buried at proper depth, will nee physical protection where it emerges from the ground, and can not enter a building if it is only marked type USE, but dual rated USE/RHW can enter buildings.

 

[kolega]

i was kind of debating if i should run 3 wire or wire to that shop

 

[mopowr steve]

Don't forget to run seperate ground since it's a sub panel. So make that a 4wire or what's commonly called (trailer feeder)

 

[FionaZuppa]

need to trench anyways, why not PVC it?

 

[ac.electric]

I agree with mopowr Steve
If your trenching
Run pvc
Safer and better


Sent from my iPhone using Tapatalk

 

[kolega]

i was thinking about pvc but its gonna be a lot more expensive and time consuming. i actually talked to inspector and he said it was fine to run 3 wire as long as i pond the ground rod on the shop side. any thoughts on that?

 

[kwired]

i was thinking about pvc but its gonna be a lot more expensive and time consuming. i actually talked to inspector and he said it was fine to run 3 wire as long as i pond the ground rod on the shop side. any thoughts on that?

Unless you are on prior to 2008 NEC there is no longer a choice - must be separate equipment grounding conductor - exception is only for existing installations, and still has conditions before it is allowed. Grounding electrode is needed at the separate structure as well regardless of whether you have three or four wire feed.

However if you can somehow arrange it so there is no service disconnecting means before the run to the shop- then you still have service conductors and no EGC is needed. Say you hit meter, then go from meter to house with one line - install service disconnect for house in or on the house then run a second line from meter to the shop and install a separate service disconnect in or on the shop. That is NEC compliant - some POCO's may still want you to hit a service disconnect immediately after the meter if you have one of those POCO's then you don't have much choice.

 

[kolega]

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I was thinking more like doing 320amp meter with 2 200 amp breakers servings as disconnects than do 200 sub panel inside the house and one 200 amp panel for the shop. Than I guess my wires to the shop are becoming feeders so they will have to be 250kcmil or they could still be 4/0?

 

[kwired]

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I was thinking more like doing 320amp meter with 2 200 amp breakers servings as disconnects than do 200 sub panel inside the house and one 200 amp panel for the shop. Than I guess my wires to the shop are becoming feeders so they will have to be 250kcmil or they could still be 4/0?

They can be 4/0 as long as calculated load isn't higher then their ampacity of 180 amps.
180 amps is not a standard overcurrent device so you can use next higher which is 200.

The fact they are feeders means you will need an equipment ground conductor as mentioned before unless you happen to still be on a code older then 2008 (maybe 2005 can't remember which year that change was made).

 

[kolega]

What would u recommend to do for service? Should in buy meter with 2 200 amp breakers or should I do meter and separate 200 amp disconnects on each side?

 

[kolega]

What would be my best option?to do meter with 2 200 amp breakers serving as disconnects or should I buy meter with 2 separate 200 amp disconnects

 

[Little Bill]

What would be my best option?to do meter with 2 200 amp breakers serving as disconnects or should I buy meter with 2 separate 200 amp disconnects

I would do as kwired said and use the double lugs on the meter to feed two 200A disconnects, one at the house and one at the garage/shed or whatever you're calling the other building.
This is NEC compliant for residential.
The conductors to each building would be service entrance conductors and not feeders. Then you only need 3 wire.

 

[ActionDave]

I would do as kwired said and use the double lugs on the meter to feed two 200A disconnects, one at the house and one at the garage/shed or whatever you're calling the other building.
This is NEC compliant for residential.
The conductors to each building would be service entrance conductors and not feeders. Then you only need 3 wire.

:thumbsup:

 

[kolega]

But aren't all the disconnects suppose to be grouped together at one spot?

 

[kwired]

But aren't all the disconnects suppose to be grouped together at one spot?

Each building's supply disconnects (service or feeder supplied) - yes

Entire site - no. Some POCO's may still have their own rules and want a main service disconnect at or near their metering equipment.

 

[Little Bill]

But aren't all the disconnects suppose to be grouped together at one spot?

Look at 230.40 Excpt 3

Exception No. 3: A single-family dwelling unit and a separate
structure shall be permitted to have one set of service entrance
conductors run to each from a single service drop
or lateral.

 

[JFletcher]

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I was thinking more like doing 320amp meter with 2 200 amp breakers servings as disconnects than do 200 sub panel inside the house and one 200 amp panel for the shop. Than I guess my wires to the shop are becoming feeders so they will have to be 250kcmil or they could still be 4/0?

Must be one heck of a shop to spec a 200A panel. 175' of 2" PVC conduit, sweeps, LBs and fittings is not very expensive; probably less than renting a trencher for half a day.

 

[kolega]

the guy is trenching for gas and water to the shop anyways so ill just throw it in there at like 3 feet down. i finaly made up my mind on service im gonna do 400 amp meter with 2 200 amp breakers built in for disconnects than run 250 250 250 3/o to the shop and pond the ground rod by the main breaker panel there. and for house ill run 3/0 3/0 3/0 and #4 for ground in 2 in pipe.

 

[kwired]

the guy is trenching for gas and water to the shop anyways so ill just throw it in there at like 3 feet down. i finaly made up my mind on service im gonna do 400 amp meter with 2 200 amp breakers built in for disconnects than run 250 250 250 3/o to the shop and pond the ground rod by the main breaker panel there. and for house ill run 3/0 3/0 3/0 and #4 for ground in 2 in pipe.

You need a a grounding electrode at every structure regardless or whether it is supplied by service or feeder conductors.

IMO 4/0 AL to shop is fine, unless you do have significant load there. Unless you have commercial type activity going on in there chances are it never sees 100 amps of load (electric heating maybe the exception)

I've done shops on farm places that are up to around 15,000 square feet, and though most have had 200 amp supply run to them I'd be surprised if they ever see much more then 50 amps of load for any extended time - really depends on what is in there for equipment and how much of it actually can/does run at the same time. Single dwelling accessory shop building with an owner with wood working or machining hobbies - one person only uses one machine at a time along with an occasional accessory machine like a air compressor or dust collector.