Installing wiring for outdoor post

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  #1  
Old 08-19-05, 12:01 AM
rockee
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Installing wiring for outdoor post

We are in the process of installing some wiring for an outside light pole. We were trying to determine if we should lay PVC conduit from outside close to where the wire will feed in to where the pole will be, or UF wire. If we use conduit, rather than laying the conduit with a string inside to pull the wire through later, I think it makes more sense and will be easier to lay the conduit with the wire inside it since there will be a few bends in the conduit. The reason for this I thought it might be too difficult to pull a 12-2 or 14-2 wire through a conduit about 60’ in length with 4 elbows. I would rather do that then putting in the wire now, since my electrician can advise me later when he gets back from vacation, will not be installing right after I putting the wire, I’d worry that the indoor-type wire might “deteriorate” outside. Which would you advise?

Would it be preferable to put in UF cable rather than indoor wire and conduit, and if so, how deep – minimum of 24”?

The run will probably be about 50-60 feet at most. For 50-60 feet is 12-2 the correct wire or can we still use the 14-2?

Even though the wire to switch is 14-2 can we use 12-2 for the run or must we stay with the 14-2?
 
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  #2  
Old 08-19-05, 05:29 AM
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Do not lay conduit with wire inside. The glue used for the conduit will destroy the insulation of the wire/cable.

Do not use NM cable outdoors at all. NM wire is not rated for wet locations. Conduit buried outside is a wet location.

While you can use UF cable outdoors and in conduit, you will find it much easier to pull the wire if you use individual conductors instead of UF cable.

Personally, I would simply use UF wire without conduit, unless the wire needed to run below a flower bed or somewhere else where it might be subject to abuse. I would use conduit only where necessary for protection.

14 gage wire is fine for a light at this distance. 12 gage would work, but might confuse someone and will be harder to pull.
 
  #3  
Old 08-19-05, 08:53 AM
rockee
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A few more questions - please...

Originally Posted by racraft
Do not lay conduit with wire inside. The glue used for the conduit will destroy the insulation of the wire/cable.
Are you saying not to use glue for the conduit or to wait for the glue to dry before feeding the wire into the conduit?

Originally Posted by racraft
Do not use NM cable outdoors at all. NM wire is not rated for wet locations. Conduit buried outside is a wet location.
I wasn’t planning to use “NM” wire.


Originally Posted by racraft
While you can use UF cable outdoors and in conduit, you will find it much easier to pull the wire if you use individual conductors instead of UF cable.
Should I then use UF cable inside the conduit – how about if I am using ľ” inside diameter conduit? That seems to have enough room. I’m not sure if local codes would let me use individual connectors.

Originally Posted by racraft
Personally, I would simply use UF wire without conduit, unless the wire needed to run below a flower bed or somewhere else where it might be subject to abuse. I would use conduit only where necessary for protection.
The wire actually is running right under a flower bed, so that was why I thought the conduit should be used.

Originally Posted by racraft
14 gage wire is fine for a light at this distance. 12 gage would work, but might confuse someone and will be harder to pull.
Why would 12 gauge wire confuse someone?

Are you saying that it is best to put a string inside and pull the wire through later? Would that work and would the string be able to pull the wire through 60 feet of conduit with 4 bends?
 
  #4  
Old 08-19-05, 09:01 AM
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Originally Posted by rockee
Should I then use UF cable inside the conduit – how about if I am using ľ” inside diameter conduit? That seems to have enough room. I’m not sure if local codes would let me use individual connectors.
You can definately use individual conductors in conduit. That's what it's for. Use THWN individual conductors in the conduit. Or don't use conduit at all and direct bury UF-B cable.


The wire actually is running right under a flower bed, so that was why I thought the conduit should be used.
Then that's a good idea. Use individual conductors in the PVC conduit.


Why would 12 gauge wire confuse someone?
Because they might accidentally think the circuit is a 20A circuit because of the presence of 12 gauge wire. Over 60 feet, 14 gauge will not be a problem, and it will be easier to pull.

Are you saying that it is best to put a string inside and pull the wire through later? Would that work and would the string be able to pull the wire through 60 feet of conduit with 4 bends?
Yes, use a strong pulling string or twine. Nylon twine is good stuff, don't use just plain cotton string through, that will probably break. Buy stranded wire and use a wire pulling lubricant and you will be just fine pulling 3 #14 stranded wires.
 
  #5  
Old 08-19-05, 09:07 AM
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You might only want to use conduit under the flower bed itself, if that is a subset of the whole run. Say, for example that your flower bed is only above 20 feet of the run. You can dig the trench, glue up 20 feet of PVC conduit, let the glue fully cure, feed the UF-B cable through those 20 feet, and lay the conduit in the trench. The rest of the UF-B cable can then be direct buried.
 
  #6  
Old 08-19-05, 10:05 AM
rockee
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Here is what I think i've leraned so far

Originally Posted by John Nelson
You might only want to use conduit under the flower bed itself, if that is a subset of the whole run. Say, for example that your flower bed is only above 20 feet of the run. You can dig the trench, glue up 20 feet of PVC conduit, let the glue fully cure, feed the UF-B cable through those 20 feet, and lay the conduit in the trench. The rest of the UF-B cable can then be direct buried.
I am new to this forum and appreciate all of the answers given. I think what looks like the best action for me is to put together the PVC conduit, glue it up, and lay it in the flower bed area, using a strong pull string inside, as suggested. As far as the actual wiring inside, I will wait for my electrician who comes back from vacation on Monday. He can use the pull string to put in whatever wire he wants. I am inclined to think what seems like the best thing is to use 14-2 UF wire so that I can use that inside of the conduit and then either use more conduit when I go under the lawn or directly bury the cable under the lawn area.

A remaining question is, assuming I’ll be using conduit and the UF cable, what is minimum depth for the conduit and minimum depth for UF cable not in conduit?
 
  #7  
Old 08-19-05, 10:06 AM
rockee
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Spelling

Please excuse my spelling above in the title ...
 
  #8  
Old 08-19-05, 10:51 AM
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If the wiring is GFCI protected before leaving the house (and I strongly recommend it), then 12" is the minimum depth (with or without conduit).

If the wiring is not GFCI protected before leaving the house, then the minimum is 18" if in conduit or 24" if not.
 
  #9  
Old 08-19-05, 03:37 PM
rockee
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GFCI - yes

Originally Posted by John Nelson
If the wiring is GFCI protected before leaving the house (and I strongly recommend it), then 12" is the minimum depth (with or without conduit).

If the wiring is not GFCI protected before leaving the house, then the minimum is 18" if in conduit or 24" if not.
Yes, it is protected. It has a GFI receptacle on the circuit - which I assume protects the entire run. I usually tend to be conservative, so I still will go down 18" with PVC conduit and use UF wire inside the conduit.
 
  #10  
Old 08-19-05, 04:03 PM
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Originally Posted by rockee
Yes, it is protected. It has a GFI receptacle on the circuit - which I assume protects the entire run.
Better make sure, they can be installed to either protect the rest of the circuit, or sometimes not to. You can tell by either testing a receptacle further down the line to see if it trips the GFCI, or by switching off the circuit breaker and pulling out the GFCI receptacle and seeing how it is wired. We can let you know how to do either of these things if you need.
 
  #11  
Old 08-19-05, 04:30 PM
rockee
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Will ask my electrician

Originally Posted by MAC702
Better make sure, they can be installed to either protect the rest of the circuit, or sometimes not to. You can tell by either testing a receptacle further down the line to see if it trips the GFCI, or by switching off the circuit breaker and pulling out the GFCI receptacle and seeing how it is wired. We can let you know how to do either of these things if you need.
I appreciate the advice. The electrician will be installing the wiring for the outside pole and making the final connections (I wish I were that knowledgeable, but I will leave this for him to do). When he does so, I'll have him check that circuit and make sure it is protected. I'll be the one installing the conduit and pull string.
 
  #12  
Old 08-20-05, 10:01 AM
rockee
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Next are the ground lights

You have all been very helpful, and so I do have a few more questions as I start to progress.

In addition to the post light, we will be installing two sets of two ground lights each towards the front of the beds on each side of the house – facing up towards the house and illuminating the beds.

1. I have seen much written about outside low-voltage lighting and pros and cons. What looks good about them is that it seems relatively easy to move them and change their positions to achieve the best lighting effects. Also, the wire can easily be put in under mulch and no conduit or deep trench is required. The “con” may be that a transformer is required and that, coupled with cost of fixtures and bulbs may make this more costly than 120V lighting. Also, I know there is a concern about voltage drop depending upon the # of lights and run lengths. Is this true about the cost (is it much more) and are there any other negatives to consider?

2. If we use the 120V lighting instead for the beds, I will need to come off of the conduit for the post light with a “T” and then lay a piece of conduit which goes from the post run to the front of the beds. Once I get there, should I then lay UF wire underground from light to light, or still use the conduit from light to light? Also, assuming that I have conduit or UF underground at the bed, do I need a piece of conduit to make the final connection between the cable and the light itself? I hope I am explaining this correctly.
 
  #13  
Old 08-22-05, 08:43 PM
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The fact you can actually do, and redo LV DIY is worth the savings, namely in the lesser labour costs.

IMO, considering the materiials alone for a 120V lighting system, one would consider an LV system.
 
  #14  
Old 08-23-05, 09:15 AM
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Consider solar powered LV lighting -- there is nothing to install except for the lights themselves, and they really work very well. They are free to operate and not really any more expensive than other LV lights.
 
  #15  
Old 08-23-05, 04:29 PM
manythumbs
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Originally Posted by ibpooks
Consider solar powered LV lighting -- there is nothing to install except for the lights themselves, and they really work very well. They are free to operate and not really any more expensive than other LV lights.
They are not any more expensive until someone steals them.
 
  #16  
Old 08-23-05, 06:54 PM
rockee
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Steal trhem?

Originally Posted by manythumbs
They are not any more expensive until someone steals them.
Is this a joke? Are there people out there who steal solar lights?

Actually, we had one once and diddn't have much luck, so may be leaning towards LV powered lights for the walk and shrubs.
 
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