*sigh* another detached garage question :(

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SeanB

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So I have spent a lot of time reading older posts and googling on the subject.

I have a detached garage 20 foot from my house. I am installing a 6/3 romex in conduit to the garage. I am going to have a 125amp panel INSIDE the garage. There WILL be phone, CAT5, and alarm wires going to the garage so I a ground back to main panel is necessary.

Questions: (Please keep short and sweet :))
1. Do I need a ground rod at the garage IN ADDITION to the ground wire coming to the main panel in the garage?

2. Is a 50 amp breaker ok in my main home panel to feed this subpanel?

3. Do I need a main breaker in my garage panel? If so is it supposed to be a 60amp?

I am in the grey area between 2005 and 2008, PLEASE help :(
 
SeanB said:
So I have spent a lot of time reading older posts and googling on the subject.

I have a detached garage 20 foot from my house. I am installing a 6/3 romex in conduit to the garage. I am going to have a 125amp panel INSIDE the garage. There WILL be phone, CAT5, and alarm wires going to the garage so I a ground back to main panel is necessary.


1. Do I need a ground rod at the garage IN ADDITION to the ground wire coming to the main panel in the garage?
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Yes, and possibly two rods, 6' apart depeding on local requirements. The GEC from the rods goes to the ground bar in the sub panel.

Is a 50 amp breaker ok in my main home panel to feed this subpanel?
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Yes
Do I need a main breaker in my garage panel? If so is it supposed to be a 60amp?
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Yes, or some other form of disconnect. Doesn't matter on subpanel main size as the Breaker in the panel from the house is protecting the circuit.

Remember, you can't run NM-B underground, conduit or not. Use UF or individual THWN or XHHW conductors.
 
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1. Do I need a ground rod at the garage IN ADDITION to the ground wire coming to the main panel in the garage?
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Yes, you will need a grounding electrode at the detached garage, take a look at 250.32(A).

2. Is a 50 amp breaker ok in my main home panel to feed this subpanel?
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Yes. a 50 amp breaker is OK to protect a 6/3 NM cable.

3. Do I need a main breaker in my garage panel? If so is it supposed to be a 60amp?
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You will need a disconnecting means at the detached garage, either outside the structure or inside nearest the point of entrance of the feeder conductors. Take a look at 225.31 and 225.32. If the panel is nearest the point of entrance of the feeder conductors you can use a main breaker as the disconnecting means.

I am installing a 6/3 romex in conduit to the garage.
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I have a quick question for you though, you do know that NM cable is not permitted to be installed in a wet location right. a conduit underground would be a wet location and you could not run NM cable in the underground conduit to the garage, you must use conductors that are listed for use in a wet location.

Chris
 
SeanB said:
So I have spent a lot of time reading older posts and googling on the subject.

I have a detached garage 20 foot from my house. I am installing a 6/3 romex in conduit to the garage. ... 3. Do I need a main breaker in my garage panel? If so is it supposed to be a 60amp? (
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I think a main breaker would be the best route to follow on this one.

As I read 225.39(D) I would say your feeder must be rated at least 60 amps.
 
Let me add one or two more comment for the OP.,,

I do not know which state you are in but if you are in progress getting the 2008 code cycle and you will have to understand there are some change along the way.

you have to use full 4 wire feeder to the detached building [ the old 3 wire feeder rules will be no longer effect with new codes ] the other reason why i say full 4 wire feeder due you mention you will have phone , cat 5 data cable , alarm cable.

now.,, the other change along the way is the way the GFCI is being used the 2005 or earlier codes the recpectale used to be GFCI'ed but when you slide in 2008 that will really change a bit.,, everything have to be GFCI'ed including the lighting circuit and garage door opener.

the last thing is check with your inspector to see which code cycle you can use depending on the date you get the permits for it.

Merci,Marc
 
Thanks everyone. I stopped by to see the inspector today and he told me a few things I will need to do:

1. Use schedule 80 where conduit comes up from grade up to 8'. (Wasn't expecting that one). Even though the LB may be schedule 40, they worry about lawnmowers, weedwackers etc and the harsh climate here eats up schedule 40 :eek:

2. #6 and larger (NM sheathed) can be run through the basement attached to floor joyces without conduit, to main breaker panel. Smaller than #6 has to be run along a board or inside a conduit.

3. No main breaker is needed in garage, he says as long as there is a breaker in the basement panel (I was like....of course I have a breaker in basement :eek:)

4. I told him I am pulling romex through there and he was like "whatever".

5. I also told him I am pulling a 12/2 NM cable to be used as travelers for a 3 way light switch and he said this has to be sheathed, or else take the ground wire out (??)

6. No expansion joints needed (17' from house to garage ?)

7. No seperate ground rod needed as long as I am bringing in a grounding conductor (4 wires). The #6/3 has a ground in there so I am good. He says you would need ground rods after a distance of 75 feet or so. Maybe this is a local rule?

Sounds pretty good to me. I know local AHJ can not undercut the NEC but it seems that there is some of that here. What thigns do you find wrong? Is the underground conduit really a wet location?? I pulled up some plumbing pipe that was laid years ago (thanks a lot local contractors) that was supposed to be my conduit for electrical. It was 2" underground :eek:

anyway that conduit was completely dry. Maybe I should use some seal fittings or something? I have pulled long runs of wire at a football stadium and it was a big joke to let the new guy (me) wait at the other end of the conduit when they blasted nitrogen through there with a parachute. It was like a geyser and I got wet and it stank like a$$ for the whole day. I was like wtf? They said it was from humidity.
 
3. No main breaker is needed in garage, he says as long as there is a breaker in the basement panel (I was like....of course I have a breaker in basement :eek:)
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You still need a disconnect.


7. No seperate ground rod needed as long as I am bringing in a grounding conductor (4 wires). The #6/3 has a ground in there so I am good. He says you would need ground rods after a distance of 75 feet or so. Maybe this is a local rule?
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False, you need a grounding electrode in your application.
 
Would the two be bonded in the sub panel (ground rod and a ground from main panel)?

To be honest I have never seen it this way. I know not every installation I have worked on (NOT my installations, I am a JE) was code compliant, but usually just the feeder ground wire was sufficient.
 
SeanB said:
Would the two be bonded in the sub panel (ground rod and a ground from main panel)?

To be honest I have never seen it this way. I know not every installation I have worked on (NOT my installations, I am a JE) was code compliant, but usually just the feeder ground wire was sufficient.
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In 2008 you will have no choice but to run 4 wires. The egc must be separate from the grounded conductor and the wire to the ground rod must be connected to the ground bar , not the neutral bar
 
Yes, the grounding electrode conductor from the ground rods would be terminated at the ground bar in your sub panel, NOT the neutral bar.
 
Dennis Alwon said:
In 2008 you will have no choice but to run 4 wires. The egc must be separate from the grounded conductor and the wire to the ground rod must be connected to the ground bar , not the neutral bar
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I lose the typing war again......:cool:
 
A/A Fuel GTX said:
NOT the neutral bar.
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I undestand that part

but what with the 4th )required) feeder wire? it goes to the ground bar along with the wire from ground rod? Something gives me a bad feeling about this.

Seriously, dont you guys think that the feeder ground that is required (by 2008) should be sized according to the largest service entrance conductor? I would need a number 6 ground along with my #6 ungrounded conductors (So much for using 6/3 UFB)

What if the service ground is say old and not so good, then I am relying on the ground path all the way out to my garage t carry the current.

It just doesnt seem right to me.
 
The ground wire with the feeder is an equipment ground and table 250.122 dictates this. In your case, it would be a #10. You are confusing the Grounding Electrode Conductor and the Equipment Grounding Conductor.
 
SeanB said:
I have a detached garage 20 foot from my house. I am installing a 6/3 romex in conduit to the garage.
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I have no idea why nobody has said anything, but the feeder cannot be NM cable. Neither can the travelers.
 
SeanB said:
Thanks everyone. I stopped by to see the inspector today and he told me a few things I will need to do:

1. Use schedule 80 where conduit comes up from grade up to 8'. (Wasn't expecting that one). Even though the LB may be schedule 40, they worry about lawnmowers, weedwackers etc and the harsh climate here eats up schedule 40 :eek:
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I agree, it's enforced the same way in my area.

2. #6 and larger (NM sheathed) can be run through the basement attached to floor joyces without conduit, to main breaker panel. Smaller than #6 has to be run along a board or inside a conduit.
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I agree.

3. No main breaker is needed in garage, he says as long as there is a breaker in the basement panel (I was like....of course I have a breaker in basement :eek:)
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I disagree, there needs to be a main disconnecting means at the detached structure. See the Six Handle Rule FAQ.

4. I told him I am pulling romex through there and he was like "whatever".
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Would you rather wire to the NEC, or wire to what the inspector will allow you to get away with? What if you get another inspector on the next inspection of this project that does care to enforce the NEC?

5. I also told him I am pulling a 12/2 NM cable to be used as travelers for a 3 way light switch and he said this has to be sheathed, or else take the ground wire out (??)
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This is erroneous. All conductors of the same circuit shall be contained in the same cable (300.3). The equipment grounding conductor (EGC) is to be installed with the conductors that will supply the fault.

Since you have an EGC included with the travellers, then you must include an EGC with the feeder conductors supplying the building. This is because you can no longer use 250.32(B)(2) of the 2005 and prior NEC - there are two paths between the buildings that are a bonding connection to the service disconnecting means.

Again, you can't use NM for the travellers either, as Larry mentioned.

6. No expansion joints needed (17' from house to garage ?)
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I'm no concrete guy, so I can't help you there. :D

7. No seperate ground rod needed as long as I am bringing in a grounding conductor (4 wires). The #6/3 has a ground in there so I am good. He says you would need ground rods after a distance of 75 feet or so. Maybe this is a local rule?
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Could be a local rule, but it sounds made up to me.

The NEC (250.32(A)) requires a grounding electrode system be used for structures supplied by feeders, such as yours. I would install to the NEC.

Is the underground conduit really a wet location??
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Yes, and the 2008 removes all doubt from this issue. 300.5.
 
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