Some specific electrical code questions...

[kook04]

The users of this forum have been very helpful to me thus far, and for that I am appreciative. I now have some specific electrical code questions.

I am putting a subpanel in my detached garage which is fed from the main panel in my house.

I know that the codes vary by locality, but my town codes enforcement office has not been very helpful at all, so I'm just looking for some answers based on the national codes. Any answers that anyone can provide will be appreciated.

1) Can "direct burial" cable be buried inside conduit (i.e., schedule 40 PVC)?

2) How deep does the cable have to be buried (in or out of the pvc)?

3) Does the wire that is run from the house to the garage need to have a "dedicated ground"?

4) Is there a limit to how many romex wires can be run through a single hole drilled in the studs in the garage?

5) Does there need to be a grounding rod for the garage if the house already has one?

I'm sorry if any or all of these questions are phrased incorrectly. I'm no expert for sure, but I want to do this job correctly and make sure it passes inspection.

Thanks again,

Kennedy

 

[kook04]

To add to the original post...

Just talked to the local codes enforcement office. There are no local codes, and my town goes solely on the national electrical codes.

 

[Torque1st]

This may help, it is for 2002 but there may be an update on the site:
http://www.selfhelpandmore.com/home...o-dwellings/wiring-a-detached-garage-2002.php

 

[mrb]

3 and 5 = yes. if the garage is new you dont need the ground rod, you need to bond the rebar - this is called a ufer ground

 

[walrus]

3 and 5 = yes. if the garage is new you dont need the ground rod, you need to bond the rebar - this is called a ufer ground

What if its on 2" of insulation?

 

[mrb]

What if its on 2" of insulation?

is there a footing? read up on ufer ground, determine if you have one, if you do -bond it, if not then drive a ground rod.

 

[Aceman]

1) Can "direct burial" cable be buried inside conduit (i.e., schedule 40 PVC)?

2) How deep does the cable have to be buried (in or out of the pvc)?

3) Does the wire that is run from the house to the garage need to have a "dedicated ground"?

4) Is there a limit to how many romex wires can be run through a single hole drilled in the studs in the garage?

5) Does there need to be a grounding rod for the garage if the house already has one?

1. Yes.
2. 18" to the top of the conduit/cable. If your going under a driveway you'll need 24 inches for that part of the run.
3. Yes, you need 4 wires total.
4. Too many wires and you'll have a bundling issue. Use 3 or less as a good rule of thumb.
5. If you're garage hasn't been built yet and you will be using rebar in the footers you must use that as a grounding electrode. If the garage is already up, you'll need to drive 2 rods. If you have a metallic water pipe entering the garage you'll need to ground to that as well.

 

[14binders]

1) Sheathed in conduit? The whole way? do you have some UF but want to install conduit for later?

2) How deep? 18" is code for most residential in conduit, but I always go 24". Bury some red tape 6" above it.

3) Ground wire? Yes, 4 wires minimum. This is an important one- You must remove the main bonding jumper inside the subpanel. It is usually a bare solid copper wire connecting the neutral and ground bus. Your entire electrical system is to be bonded at only one location- the service entrance equipment.

4) romex limit in hole? Agree with above, stick to 3 max.

5) Ground rod? Yes. Be safe and just pound some rod. You need two actually, 6' apart, and ONE continuous grounding electrode conductor from the ground bus to the last rod. Don't forget to bond any metal water pipe within 5' of bldg entrance (if you're not running plastic underground).