detached shop subpanel

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  #1  
Old 01-19-05, 09:24 PM
AA316
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detached shop subpanel

I am running power to my shop (detached). I have installed a 100A subpanel in the shop. I'm feeding it off of a 60A breaker from the main panel using #2 for the two hots and neutral. My question is on grounding it. I have seen different methods for grounding i.e. a feeder wire from the ground bus of the main panel or using a grounding rod (sometimes two grounding rods). Which way should I use and if using the grounding rod how do I know if I need one or two of them? Also, I am using a separate bus for the ground and neutral at the sub panel.

2nd question:

While searching for information on my main panel (Federal Pacific Electric) I keep seeing stories about them catching fire and not being a good panel. How do I find out if my panel is one of the bad ones?

Thanks in advance for any help you can give me.
 
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  #2  
Old 01-19-05, 09:38 PM
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The grounding wire from the main panel, and the grounding rod, are two different grounding systems serving two different purposes. Both are necessary. To decide on one grounding rod or two, it's best to ask your local inspector. Different areas use different rules. It depends somewhat on the type of soil in your area.

Whether or not your FPE panel is unsafe might depend on how old it is. Note that FPE never did acknowledge the hazards of their product. I've never seen a list of safe and unsafe FPE panels. I think you need to assume that it is unsafe and start planning for its replacement.
 
  #3  
Old 01-19-05, 09:47 PM
AA316
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So I will need to run a four wire feeder (2 hots, 1 neutral and 1 ground) from the main panel and connect the ground from the main panel AND a grounding rod to the ground bus in the sub? Is that correct? What gauge wire does the feeder for the ground have to be from the main panel?

Thanks for the help
 
  #4  
Old 01-19-05, 09:52 PM
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Some info.
Federal Pacific Electric

http://www.inspect-ny.com/fpe/fpepanel.htm
 
  #5  
Old 01-19-05, 09:58 PM
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If you used #2 for the hots and neutral, then use at least #8 for the grounding conductor between panels. This is the EGC, the equipment grounding conductor. It primarily protects against inside faults.

Use #6 in conduit or #4 to connect the panel to the grounding rod(s). This is the GEC, the grounding electrode conductor. It primarily protects against outside faults.
 
  #6  
Old 01-20-05, 07:33 AM
AA316
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Thanks for the help John and Gwiz. After reading the article that Gwiz supplied, would it be advised to change main panels even though mine is not labeled "Stab-Lok" or is there potential problems with ALL Pacific Electric panels. My home was built in 1983, I just purchased it 2 years ago. Is there a way to test my panel and breakers to see if they are working properly or if they are faulty (without burning the house down)? I'm really concerned now about adding this new load to the panel that may be faulty.

Thanks for any input!
 
  #7  
Old 01-20-05, 12:09 PM
AA316
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Ok, I have decided to go ahead and change the panel out (better safe than sorry). I would like to go ahead and upgrade the panel from 150A to 200A since I'm changing it out anyway. My question is; How do I determine whether the meter and the feeder from the meter will support the new 200A panel?

Thanks again!
 
  #8  
Old 01-20-05, 02:09 PM
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Start by calling your power company.
 
  #9  
Old 01-20-05, 04:00 PM
AA316
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One last (hopefully) question I have; What exactly will the inspector be looking for before he can pass it? Will he only need the hots, nuetral and ground to be in place in the new box or will he need all of the circuits wired prior to approval?

The reason I ask is that I am trying to limit the amount of time that the power is turned off. I figure if I go ahead and install the new panel next to the old one, Then have the power company shut off power, move just the hots, nuetral and ground over to the new box, have it inspected and restore power at that point. Then I would finnish wiring the circuits after power is restored. Is that plan feasable? This is assuming of course that my current meter and feeder will support 200Amps and new wire doesnt have to be ran.

Thanks for any input
 
  #10  
Old 01-20-05, 08:18 PM
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Every city is different
I cant say what you need to do. ask your city inspector.
What I have done.
Have the power company OK the location of the new meter.
Go to the city get permits and ask them what wire sizes for panel size
and ground wire size.
Install the new panel and completely wire the panel.
Tap power from the old panel to the new panel.
I had one friend add a GFI to the old panel then feed the new panel (temporally only)

Call the inspector, may come over in 3 days.
If you get an ok, the inspector sends the paper work to the power company.
The power company will run the wire to the rain head and replace the meter.

You may ask the power company how long it will take them to come out after inspection.
Some times the power company will send their inspectors in addition to the city's.
 
  #11  
Old 01-22-05, 11:03 AM
AA316
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Originally Posted by John Nelson
If you used #2 for the hots and neutral, then use at least #8 for the grounding conductor between panels. This is the EGC, the equipment grounding conductor. It primarily protects against inside faults.

Use #6 in conduit or #4 to connect the panel to the grounding rod(s). This is the GEC, the grounding electrode conductor. It primarily protects against outside faults.
Can this be the bare copper wire or does it have to be in sheathing?
 
  #12  
Old 01-22-05, 12:20 PM
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Except in some situations (e.g., spas, pools, hot tubs, ...), a grounding wire can be bare.
 
  #13  
Old 01-24-05, 05:51 AM
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If your using #2 for the hots why not feed the garage panel with a 100A panel?? Also, if you run a equipment ground wire from the main panel to the sub panel you don't want to run a grounding elctrode conductor to the ground rod. You can do 1 of 2 things, 1. Run 2 hots, 1 neutral, and 1 ground wire or 2. Run 2 hots, 1 neutral, and put a ground rod at the garage.
Always follow local codes and the NEC
 
  #14  
Old 01-24-05, 07:24 AM
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Also, if you run a equipment ground wire from the main panel to the sub panel you don't want to run a grounding elctrode conductor to the ground rod
I disagree. Code requires a grounding rod at each building regardless of whether or not you run an ECG. These are two different grounding systems serving two different purposes.
 
  #15  
Old 01-24-05, 12:08 PM
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Exclamation

OOps, John is correct. a grounding electrode shall not be required where only 1 branch circuit supplies the building and the circuit includes an egc.

I have used 20-32 (b) (2) without trouble (2002 code, I don't have the 2005 with me) That is, not running a egc, and connecting the grounded circuit conductor to the disconnecting means and to the new grounding electrode at the separate building.
 
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