Junction box

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  #1  
Old 12-05-05, 12:34 PM
Gettinitdone
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Junction box

I recently connected wire that supplies my Mailbox lampost to the wire that is fed into the home. The connection resides in a weather proof junction box. When I connected the black, white and ground I taped the wire nuts for the black and white connections but I didn't tape the wire nut that connected the ground. Will there be a problem there?
 
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  #2  
Old 12-05-05, 12:40 PM
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Tape over wire nuts should never be necessary.

I'm not sure what this "wire that is fed into the home" is. Can you clarify?

The cable running to the lamppost should be wet-rated (e.g., UF-B), and should normally be GFCI protected, should be buried a minimum of 12" deep, and should be protected by conduit down the to the bottom of the trench.
 
  #3  
Old 12-05-05, 12:42 PM
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Tape is not required for any wire nut, so no, that should not be a problem.

Now, if you use tape because you have problems with wire nuts coming off without tape, then you may have a problem with your connections. If the wire nut is properly installed, the wires are snug, the nut won't come off, and there is no bare wire showing (except, of course, with the bare ground wires).
 
  #4  
Old 12-05-05, 12:45 PM
Gettinitdone
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Underground

John:

Thanks for the quick reply. The wire is underground 12-2. I don't remember UF-B, but it is definitely rated for underground (I bought it at Home Depot) and I ran it in schedule 40 PVC. I thought that wire nuts had to be taped, but am glad that isn't really necessary. I have a GFCI in the outlet box that is also on the Mailbox post. Sounds like I am ok.
 
  #5  
Old 12-05-05, 12:47 PM
Gettinitdone
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Bare wire

Nope, the wire nuts were snug. I was concerned because the ground wires show where they aren't covered by the wire nuts. Sounds like I'll be ok here. Thanks.
 
  #6  
Old 12-05-05, 12:51 PM
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The wire needs to be GFCI protected where it leaves the house.
 
  #7  
Old 12-05-05, 01:08 PM
Gettinitdone
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Leaves the house

So should I have a GFCI circuit in the panel for this application? There is regular Romex 12-2 coming out of the panel through the joists in the basement then it is connected the the Underground 12-2 in a Junction box on the basement wall the underground then goes up the wall through an LB joint and through the basement wall through the front porch and out the 8 inch block into conduit about 10" deep then up to the outdoor junction box on front of porch where it is connected to two pieces of outdoor 12-2 - one goes up to the mailbox post lamp (photo eye) with constant power, the other goes to an outlet box in the mailbox that has a gfci outlet in it.
 
  #8  
Old 12-05-05, 01:27 PM
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I would use a faceless GFCI at the junction box where the NM cable is connected to the UF cable.
 
  #9  
Old 12-05-05, 01:29 PM
Gettinitdone
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Faceless GFCI

Ok so just before the underground wire leaves the basement in the junction box where it is connected to the regular Romex. How do I reset that if it trips? Is is just going to trip the breaker?
 
  #10  
Old 12-05-05, 01:30 PM
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Cable or wire in PVC conduit that is not GFCI protected must be buried at least 18" deep. Cable that is GFCI protected may be buried as little as 12" deep. A GFCI at the end of the cable does not protect the cable itself. So if you want to qualify for the 12" burial depth, you need the GFCI (breaker or receptacle) to be in (or mounted to) the house. A GFCI receptacle in (or mounted to) the house is what most people use.

Mount the GFCI receptacle (or faceless GFCI) where you can get to it to reset it. All junction boxes must be permanently accessible anyway. I'd just put it in that basement junction box (which is of course permanently accessible, right?).
 
  #11  
Old 12-05-05, 01:33 PM
Gettinitdone
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Gfci

So is it possible for me to just use a GFCI outlet (plug) in the box where I joined the Romex to the Underground wire or is it better to use the faceless GFCI that is mentioned earlier?
 
  #12  
Old 12-05-05, 01:35 PM
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You can use either one, a faceless GFCI or a GFCI receptacle. I prefer a faceless GFCI in areas where someone might be tempted to use the receptacle and I don't want them to.
 
  #13  
Old 12-06-05, 07:00 AM
Gettinitdone
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Here's my plan

Alright, so I'll put a faceless GFCI inside the basement where the underground wire is junctioned to the regular romex. I'll then have GFCI protection where it leaves the house and then GFCI protection outside at the mailbox.

Do you think it is advisable to put other outlets inside the basement on this circuit or just leave it by itself and wire the other necessary outlets in the basement to another circuit? I plan to make the circuit going outside a 20amp and have plenty of room in the panel to wire other basement outlets to a 15amp or 20amp if I want to.
 
  #14  
Old 12-06-05, 07:25 AM
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An entire 20-amp circuit to serve just one lamp post is overkill, unless that lamp post has a receptacle on it. I'd say you can certainly put a few receptacles on the same circuit as one lamp post.
 
  #15  
Old 12-06-05, 08:34 AM
Gettinitdone
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receptacle on lamp post

The lamp post does have a receptable on it. I'll plug christmas lights into it and whatever electrical stuff I end up needing to run in the front of the house.
 
  #16  
Old 12-06-05, 10:00 AM
Bob33
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I think if the UF is installed in PVC conduit the whole run then it must be derated in ampacity since the rating is based on not being enclosed. Might someone have a view on this?
 
  #17  
Old 12-06-05, 10:13 AM
Gettinitdone
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Is that a problem?

Bob33 is what you are asking a potential problem. The UF wire is enclosed in schedule 40 pvc for the entire run except for approx. 4 feet where it come inside the basement wall and about 1 foot where the wire is extended up through the top of the brick mailbox.

Why does encasing in conduit "derate" the ampacity and what is ampacity?
 
  #18  
Old 12-06-05, 03:22 PM
Bob33
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I believe I've read in some other forums where UF is not rated for installation in conduit as it is designed for direct burial. When some wiring is enclosed in conduit, due to poorer heat dissipation, it cannot carry rated amps and is down-graded in ampacity (a 20 amp circuit might now be fused at 15 amps). Try :http://************/c7kdy for some of these issues disscussed. I'm not positive on your issue and that's why I suggested that someone might have a view on this issue in my original post. The link I gave earlier suggests the need for GFI in the circuit depending on design. In the real world, likely not an issue IMO.
 
  #19  
Old 12-06-05, 03:46 PM
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derating is where you lower the rating. Derating the ampicity would be lowering the number of amps that can, or should be, transported through a cable.

While using conduit for UF is overkill (except where needed for physical protection), there is no need to derate in this situation.
 
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