Subpanel - SubPanel Feed

[BTSaw]

Electrician installed a 200A service panel in new house. He also installed a 100A subpanel in my new detached garage. I believe he ran a 2-2-4 URD cable instead of a 2-2-2-4 cable between the house and shop. Can’t confirm cable type at this time. Now he wants to install a new 100A subpanel next to the 200A service panel in the house, and then move the 100A garage feeder from the 200A service panel to the new 100A house subpanel. So then the 100A house subpanel feeding my 100A garage subpanel. By doing so, he does not have to replace the 2-2-4 cable between the house and detached garage. Is a 2-2-2-4 still need between the two 100A subpanels?

 

[Alchymist]

Detached garage will still require 4 wire feed.

 

[pattenp]

Any feeder/branch circuit providing 240/120V after the first main disconnect has to be four conductor. You have to have that separated equipment ground from the house sub-panel to the garage sub-panel. Period.

 

[wyliesdiesels]

U need a 4-wire feeder regardless of where its fed from. If the electrician screwed up and put the wrong cable in, that's on his dime to change it!

Your description of what would feed what is kinda confusing as you said a new 100a sub could be put in next to the 200a service main in the house so the 100a garage feed could be moved to the 100a sub in the house! Huh?

If I understand what you're saying and if it were my house I would not feed a garage from a house sub-panel due to possible voltage drop and overload, depending on what the connected load is. The best place to feed from is obviously the service main.

 

[BTSaw]

Building new house and detached garage. Electrician filled up my 200A service panel. I have no spare slots for any breakers, so he wants to install a subpanel next to the service panel to create additonal breaker slots. I don't know what else to do.

 

[hidollartoys]

Fire your electrician!!!!!!!

 

[forced induction]

How big was the 200A panel? Besides not big enough. did it have 40 slots?

Maybe you can change some circuits to tandem breakers to make room for the new 100A breaker?

Also why Is there a number 4 ground? I think per code you only need a number 8 for 100A. Although since you only have 2-#2's maybe that is why Besides the point but still

 

[wyliesdiesels]

Building new house and detached garage. Electrician filled up my 200A service panel. I have no spare slots for any breakers, so he wants to install a subpanel next to the service panel to create additional breaker slots. I don't know what else to do.

Where is your garage feed currently connected? The 200amp main? Or is it brand new and doesn't have a place to hook up? As someone stated, the tandem breaker idea may work!

 

[pattenp]

How big was the 200A panel? Besides not big enough. did it have 40 slots?

Maybe you can change some circuits to tandem breakers to make room for the new 100A breaker?

Also why Is there a number 4 ground? I think per code you only need a number 8 for 100A. Although since you only have 2-#2's maybe that is why Besides the point but still

The ground is a #4 because that is the size the manufacturer used in the #2 cable assembly.

 

[BTSaw]

Still fighting with electrician. Can't fire him because he works for the builder. He wants to run a #4 bare wire and use it as the ground, since he only ran a 2-2-4 URD feeder for the detached garage. I told him a #2 insulated wire is needed for the neutal wire since the hot legs are #2. The #4 URD wire can be used as ground. He said the neutral and ground can both be #4 wires. I said he is wrong. I'm I correct?

I also read in the posting that #2 AL is rated at 95 amps. Where do I get a 95A Square D breaker for the subpanel feeder? Thanks.

 

[Aceman]

The only code compliant fix is to replace the feeder. Simply adding a 4th wire to it doesn't make it okay. 300.3(B) is the article for your reference.

#2 AL the way you have it installed is 90 amp wire and they do make 90 amp breakers.

 

[lakee911]

Also, if the URD cable/bundle does not carry any additional recognized ratings it is not recognized by the NEC. Typically it's used for utility distribution and as such it can not legally be used for installations under NEC jurisdiction. The utility isn't governed by the NEC so this is typically used underground before the meter.

Also, some direct bury wire isn't recognized for indoor use. Around here, the inspector would want a JB outside to transition to indoor wire--wouldn't even allow 12" to pass through the wall into the panel.

Your builder is the responsible party. Take it up with him and give him the oppurtunity to make it (or have his sub make it) right. If he's unwilling, you can make sure to be present for inspections and the county/city/state will make him make it right. I'd look over the rest of his work closely too.

 

[pattenp]

The only code compliant fix is to replace the feeder. Simply adding a 4th wire to it doesn't make it okay. 300.3(B) is the article for your reference.

#2 AL the way you have it installed is 90 amp wire and they do make 90 amp breakers.

I think to the strict interpretation of 300.3(B) you're correct. The wire being URD is a cable by definition of being more than one conductor and sold as an assembly. I don't know if an inspector would even catch it if you added an additional individual conductor of the same type. The only thing that may cause a question is the remarking of the #4 neutral as a ground. The inspector would have a hard time seeing that the cable wasn't a four conductor URD in the first place. What may be the show stopper on inspection is if the inspector says, "hey you can't run URD to inside the structure."

 

[wyliesdiesels]

What a mess! Definitely take it up with the builder! If u hired the builder/general, then the subs are his responsibility, NOT yours! It will be his problem if/when it doesn't pass!