Enhancing existing wiring to detached garage

jimmy21 · 07-03-2008, 04:28 PM

what do you mean. I know you know what it says, since youve been refferencing it, but....

225.39 says all disconnects for feeders must be 60A.

Quote:

Originally Posted by chris75

Section 225.39 (D)

In other words, you can easily run #12 feeder to the garage, but your disconnect would have to be rated at 60 amps.

So youd be saying to run a number 12 for a feeder. And use a 60 amp breaker to disconnect that feeder.

chris75 · 07-03-2008, 04:54 PM

Quote:

Originally Posted by jimmy21

what do you mean. I know you know what it says, since youve been refferencing it, but....

225.39 says all disconnects for feeders must be 60A.

So youd be saying to run a number 12 for a feeder. And use a 60 amp breaker to disconnect that feeder.

The disconnect is at the detached structure. So in a nutshell, I can easily run a 12-3 feeder out of the house panel with 20a OCP, when I get to the detached structure, I install a MIN. 60amp disconnect ( weather it be a main breaker panel or some other Suitable for Service Equipment disconnect) and be on my marry way.

Hope this helps!

jimmy21 · 07-03-2008, 05:55 PM

if you did that you feeder wouldn't have a 60 amp disconnect. It would have a 60 amp disconnect downstream from it. You are misinterpreting the code. Flat out. Its saying the 60 amp disconnect must disconnect the feeder. The way your reading it makes no sense at all. Why would the NEC care what size breaker you have downstream of what its talking about protecting?

You can do what you saying legally, if its attached garage, where 225.39 would have nothing to do with it. And further more if its not getting inspected, who gives a crap as long as its safe

justinperkins · 07-03-2008, 05:57 PM

That's great that this thread inspired a spirited discussion, but I think from the fourth post and beyond it was way above my head and far more information that I was seeking.

Remember I closed my OP with this:

Quote:

Originally Posted by justinperkins

It's an old house and I'm trying to make do with what I have for the time being until we have enough money to have the house rewired and a new panel installed.

Basically I was trying to determine if my existing circuit is maxed out or if it is OK to add the additional fluorescents I am referring to. Also, in the case that it is maxed out, can I simply add a subpanel in the garage, add two breakers and then feed my fluorescents from one breaker and the outlets from another.

wrt to adding a ground spike at the shop, I would love to do that since it would give my shop grounded outlets (remember my house is not grounded).

btw, nothing is getting inspected, I just want it safe.

HouseHelper · 07-03-2008, 06:21 PM

Quote:

wrt to adding a ground spike at the shop, I would love to do that since it would give my shop grounded outlets (remember my house is not grounded).

Having a ground rod has nothing to do with having grounded outlets. The ground of the receptacles are connected to the panel ground (main or sub) which are ultimately bonded to the neutral (at the main service). A ground rod provides protection from lightning and high voltage. It does not provide short circuit protection.

MacRoadie · 07-03-2008, 06:29 PM

Quote:

Originally Posted by chris75

The disconnect is at the detached structure. So in a nutshell, I can easily run a 12-3 feeder out of the house panel with 20a OCP, when I get to the detached structure, I install a MIN. 60amp disconnect ( weather it be a main breaker panel or some other Suitable for Service Equipment disconnect) and be on my marry way.

Hope this helps!

Ok, now I'm confused. If you install a 20a breaker at the main panel, then run your 12-3 feeders to the garage, then install a 60a disconnect at the garage end, what purpose does the disconnect serve? If your overcurrent protection is determined by the 20a breaker at the service panel, why would the disconnect be rated at 40a greater than the overcurrent protection will allow?

jimmy21 · 07-03-2008, 07:00 PM

Quote:

Originally Posted by MacRoadie

Ok, now I'm confused. If you install a 20a breaker at the main panel, then run your 12-3 feeders to the garage, then install a 60a disconnect at the garage end, what purpose does the disconnect serve? If your overcurrent protection is determined by the 20a breaker at the service panel, why would the disconnect be rated at 40a greater than the overcurrent protection will allow?

the purpose of the disconnect would be so you can manually shut off power from inside the garage. It would be safe, but not up to code if it were a detatched garage. You would be required to run at least 2 #6s and an #8 nuetral, protected by a 60a breaker with driven ground rods.

The purpose for ground rods, is to make sure the ground and your grounding system in your house, along with your water pipes, all have the same potential.

MacRoadie · 07-03-2008, 07:08 PM

Quote:

Originally Posted by jimmy21

the purpose of the disconnect would be so you can manually shut off power from inside the garage. It would be safe, but not up to code if it were a detatched garage. You would be required to run at least 2 #6s and an #8 nuetral, protected by a 60a breaker with driven ground rods.

The purpose for ground rods, is to make sure the ground and your grounding system in your house, along with your water pipes, all have the same potential.

I understand the need for the disconnect, and the purpose of the ground rod (wasn't questioning the ground). The 2 #6's, 60a breaker, etc. makes much more sense to me than a 20a and 12-3.

chris75 · 07-03-2008, 10:33 PM

Quote:

Originally Posted by jimmy21

if you did that you feeder wouldn't have a 60 amp disconnect. It would have a 60 amp disconnect downstream from it. You are misinterpreting the code. Flat out. Its saying the 60 amp disconnect must disconnect the feeder. The way your reading it makes no sense at all. Why would the NEC care what size breaker you have downstream of what its talking about protecting?

The disconnect at the outbuilding is not protecting anything, its a disconnect and the NEC REQUIRES it to be rated at 60 amps. Flat out.. I dont know why you find this so hard to believe. and I already asked you to PM me if you have any questions on this instead of turning this thread into something its not.

Quote:

Originally Posted by jimmy21

You can do what you saying legally, if its attached garage, where 225.39 would have nothing to do with it. And further more if its not getting inspected, who gives a crap as long as its safe

are you even an electrician?

chris75 · 07-03-2008, 10:37 PM

Quote:

Originally Posted by MacRoadie

I understand the need for the disconnect, and the purpose of the ground rod (wasn't questioning the ground). The 2 #6's, 60a breaker, etc. makes much more sense to me than a 20a and 12-3.

Its a DISCONNECT not overload protection, the nec wants it rated at 60 amps, plain and simple...

junkcollector · 07-03-2008, 10:39 PM

Quote:

Originally Posted by jimmy21

It would be safe, but not up to code if it were a detatched garage.

You would be required to run at least 2 #6s and an #8 nuetral, protected by a 60a breaker with driven ground rods.

Why not?

Where in the NEC does it say that I cannot run, say a 10/3 feeder to a detached structure? (It doesn't!)

2008 NEC requires a seperate nuetral and ground when you run a feeder. Read 250.32.

Quote:

Originally Posted by jimmy21

The purpose for ground rods, is to make sure the ground and your grounding system in your house, along with your water pipes, all have the same potential.

No, the ground rods have nothing to do with keeping anything at the same potential. Bonding everything together keeps things at the same potential.
Ground rods are supposed to guard against overvoltage, such as lightning and such.

chris75 · 07-03-2008, 10:41 PM

Quote:

Originally Posted by jimmy21

the purpose of the disconnect would be so you can manually shut off power from inside the garage. It would be safe, but not up to code if it were a detatched garage. You would be required to run at least 2 #6s and an #8 nuetral, protected by a 60a breaker with driven ground rods.

If you dont believe me, then take that statement over to Mike Holts Forum and post that question. I dont know where your reading that the required DISCONNECT must be fed by a certain size wire?

chris75 · 07-04-2008, 11:00 AM

Jimmy, have you seen the light yet?

white29 · 07-04-2008, 01:54 PM

Jeez, I was going to ask some questions about my own sub panel project, but I'm a little scared to now!

chris75 · 07-04-2008, 02:12 PM

Quote:

Originally Posted by white29

Jeez, I was going to ask some questions about my own sub panel project, but I'm a little scared to now!

I wanted to finish this by PM, its was an nec issue, but please, do not feel scared to ask a question, this thread got hi-jacked and it happens from time to time.