Laying underground cable myself

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  #1  
Old 04-26-06, 11:32 AM
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Laying underground cable myself

My original plan was to put the meter pole right at the pump and have the power company lay the cable. But cost difference is making me change the plan. New plan is to set up the meter pole at the entrance of my parcel, and extend the power for about 100' myself. Please check this plan for me:

1) Main disconnect: 60A circuit breaker (I am limited to 60A pump only service). Nothing else for this panel.
2) Pump subpanel: 100A panel (smallest I could find at Lowes). One 20A DP circuit breaker (1.5 HP pump) and one 15A SP circuit breaker (pump timer).
3) Run 2-2-4-6 URD direct burial cable between main and pump subpanel.

A few more questions:

4) Do you recommend another main circuit breaker (60A) at the 100A pump panel?

5) Do you recommend another grounding rod at the pump panel?

6) Do you recommend a surge suppressor at the pump panel to protect the pump from potential lightning strike?

7) In case I cannot buy 2-2-4-6 URD direct burial cable from Lowes or HomeDepot, can I lay 2" sch80 pvc pipe and pull 3 #4 and 1 #6 copper wires through the conduit? Is pulling wires a one man job?

Thanks.
 
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  #2  
Old 04-26-06, 05:18 PM
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> 1) Main disconnect: 60A circuit breaker
> (I am limited to 60A pump only service).
> Nothing else for this panel.
Okay.

> 2) Pump subpanel: 100A panel (smallest I could find at Lowes).
Main lugs? Doesn't matter.
A 125A 8-space panel might be the smaller.
A 100A disconnect (lugs only) is usually the smallest.


> One 20A DP circuit breaker (1.5 HP pump) and
Sounds small.

> one 15A SP circuit breaker (pump timer).
Okay.


> 4) Do you recommend another main circuit breaker (60A)
> at the 100A pump panel?
No reason. You are allowed 6 handles. Two is pretty reasonable.


> 5) Do you recommend another grounding rod at the pump panel?
I didn't know that it is optional. If you have a steel well casing, ask your inpector if he will approve that. I think he should.


> 6) Do you recommend a surge suppressor at the pump panel
> to protect the pump from potential lightning strike?
Nothing beats good grounding. I assume the lightning risk is low.


> 7) In case I cannot buy 2-2-4-6 URD direct burial cable from Lowes or
> HomeDepot, can I lay 2" sch80 pvc pipe and pull 3 #4 and 1 #6
> copper wires through the conduit?
Yes. Did you ask for 100A mobile home cable? It's aluminum.


> Is pulling wires a one man job?
Sure, the other person greases and pushes.
If the distance is short, you can do it yourself.
But at 100', you could end up walking a mile or so.
 

Last edited by bolide; 04-27-06 at 09:34 PM.
  #3  
Old 04-26-06, 09:12 PM
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[A 100A disconnect (lugs only) is usually the smallest.]
Saw that at Lowes. Yes, it was the smallest of what they had. Will use that.



[> One 20A DP circuit breaker (1.5 HP pump) and
Sounds small.]
1.5 hp=1200 W=5A @240V
I was afraid 20 was too large.
I will check NEC.

[>5) Do you recommend another grounding rod at the pump panel?
I didn't know that it is optional. If you have a steel well casing, ask your inpector if he will approve that. I think he should.]
I am in Central Florida and shallow wells produce enough water for small irrigation. Plastic well casing and plastic well point. I will not use another grounding rod.

[> 6) Do you recommend a surge suppressor at the pump panel
> to protect the pump from potential lightning strike?
Nothing beats good grounding. I assume the lightning risk is low.]
Actually, central Florida is the lightning capital of the nation. Does surge supressor really work?


[> 7) In case I cannot buy 2-2-4-6 URD direct burial cable from Lowes or
> HomeDepot, can I lay 2" sch80 pvc pipe and pull 3 #4 and 1 #6
> copper wires through the conduit?
Yes. Did you whether for 100A mobile home cable? It's aluminum.]
Yes, I know 2-2-4-6 URD Direct Burial is aluminum, 100A mobile home cable.


]> Is pulling wires a one man job?
Sure, the other person greases and pushes.
If the distance is short, you can do it yourself.
But at 100', you could end up walking a mile or so.]
Thanks. By the way, how do I pull wires through such a small size pipe? I heard about vacuum cleaner sucking a ball, but how can I run a vacuum without power? Pull a twine after adding each 10' section of pipe?

Thanks.
 
  #4  
Old 04-26-06, 10:08 PM
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[> One 20A DP circuit breaker (1.5 HP pump) and
Sounds small.]
1.5 hp=1200 W=5A @240V
I was afraid 20 was too large.
I will check NEC.

>> 15 amp double pole breaker will do the job



]> Is pulling wires a one man job?
Sure, the other person greases and pushes.
If the distance is short, you can do it yourself.
But at 100', you could end up walking a mile or so.]
Thanks. By the way, how do I pull wires through such a small size pipe? I heard about vacuum cleaner sucking a ball, but how can I run a vacuum without power? Pull a twine after adding each 10' section of pipe?
>> the best methold to do this is just join all the pipe together and buried then get a fish tape to pull the wire thru the pipe

please note that many people done pulling twine after every section of pipe together it kinda take up more time and also if the PVC glue get inside of it and it will make the twine stuck so best thing is just run it straght many fish tape can go up to 200 feet in length

Merci, Marc
 
  #5  
Old 04-27-06, 03:37 AM
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> 1.5 hp=1200 W
>=5A @240V
Is this your math or the manufacturer's?

> I was afraid 20 was too large. I will check NEC.
FLA=5 is very good for a 240V single-phase. That's like pf=1.
The manufacturer should give you instructions.


> Plastic well casing and plastic well point.
> I will not use another grounding rod.
Depends on whether you have a "structure".


>Does surge supressor really work?
The self-sacrificial type do some extent.


> I heard about vacuum cleaner sucking a ball,
> but how can I run a vacuum without power?
A generator.


> Pull a twine after adding each 10' section of pipe?
You'll get glue all over your twine. A fish tape is best. What's the distance?
 
  #6  
Old 04-27-06, 08:04 AM
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For 100', and only one pipe, there's no question, even if power is available. I'd rather wind back up the Klein stainless steel fishtape than drag out and put away the vacuum.
 
  #7  
Old 04-27-06, 04:06 PM
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Thanks for the replies. I think I can buy direct burial cable, and wouldn't need to pull (and push) wires through conduit. I have just one more question and hope it is my last for this job.

Lowes lists 2 aluminum cables for wire size 2-2-2-4. One is Mobile Home Feeder Direct Burial or In Conduit 75 deg C max. The other is URD Direct Burial and no mention of temperature. They have different stock numbers. Are they different? My application is 100' (max) underground run between main disconnect to subpanel (lugs only) for 60A pump only service. County inspector says, "Follow NEC."

Edit: I found the answer. The Mobile Home Feeder Direct Burial has white neutral and green ground. URD Direct Burial has one neutral, for 3 phase electrical wiring. It took a while to figure it out.

I just remembered one more question. Trenching 100' 24"+ deep (24" minimum). How long will it take? The tool rental place wouldn't give estimate. Terrain is sand, no rock, flat, no vegetation, all creared. Thanks.
 

Last edited by puter; 04-27-06 at 06:39 PM. Reason: Found answer to Question #1
  #8  
Old 04-27-06, 06:47 PM
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Originally Posted by puter
Terrain is sand, no rock...
I NEVER believe that anymore!!!
 
  #9  
Old 04-27-06, 08:24 PM
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You may be right. I have never dug 3 feet deep 100 feet long. I just have dug a few post holes about 3 feet deep and a well about 8' deep. There was no rock. I live in Florida.
 
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