Temp Work Ordeal

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blue spark

blue spark

Senior Member
Location
MN
Situation: Lake access only job on a cabin where primary has been brought in to the shoreline. Customer wants power brought in to the cabin 250' from xformer. This island is pure ledgerock. He says that next year they're bringing out a mini excavator and a blasting crew for site prep on a new addition as well as a septic system. At that time he could provide me with a trench but he wants power now. I proposed 250kcmil in schedule 80 the entire length but also told him that it would have to be redone entirely after they blast the trench. He was fine with that:-? . On a side note he wants wiremold ran through the cabin for temp power and lights in the cabin. All of it will be ripped out next year when they gut the cabin:confused:. I thought about smaller wire but there's a lake water system installed, fridge, electric range, elec hot H2O, and a power boat lift (for his float plane ;) ) so for a 200A service I'm going with the 250. I know this seems ridiculous but the money is good and we'll get the work next year as well. Any ideas on this or better solutions?
 
Other then some good headache relief medicine sounds like you have it nailed. Though I would ask him to see if he could speed up the excavation and blasting crew. That way you're not out there twice. Then again, if he is willing to drop the money for it, why not just go with scheme A.
 
I guess I was a little iffy about leaving it on the ground that long. Plus what if he takes longer than a year. There's really no foot traffic around but I guess I was wondering how you guys felt about it. The barge will not be available on the lake until next spring. Oh yeah, today he asked me if I would paint the conduit forest green. Got love these lake access jobs. Guess I better start loading the jonboat. Rolling up 250' of 250kcmil is going to be fun. Maybe I should weld pontoons on the wire trailer:rolleyes:
 
I have a certain customer who's had me re-doing certain portions of some of my finest work off and on for 10 years. Don't look a gift horse in the mouth. I'll do it whatever legal way you want it today, and re-do it another legal way tomorrow if you want to pay me again. Doesn't matter to me.
 
Blue Spark, Are you saying you plan to run 250' of sched 80 PVC right on top of the ground? If so, how will the PVC be supported on ground that probably isn't very flat if it's all ledge? Have you accounted for alot of expansion/contraction of the PVC? Will the service lateral be fused at the transformer. I'm wondering because it just doesn't seem as safe as UG or OH.
 
mkgrady said:
Blue Spark, Are you saying you plan to run 250' of sched 80 PVC right on top of the ground? If so, how will the PVC be supported on ground that probably isn't very flat if it's all ledge? Have you accounted for alot of expansion/contraction of the PVC? Will the service lateral be fused at the transformer. I'm wondering because it just doesn't seem as safe as UG or OH.
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Yes on the ground. Ledgerock is just the type of rock. It's a steady grade up to the cabin but it'll be supported I assure you. I've planned 2 expansion joints in the run and there is a meter/main at the xformer. Overhead is out of the question.
 
hardworkingstiff said:
I would look at the cost of a good generator. It could supply the power needed now, and it would be the emergency generator if needed (after the permanent power is installed).
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There will be a back-up geni but running it all the time would be a no-no. This place is right on the edge of the BWCA and it would be severely frowned upon by neighbors and DNR/USFS folks.
 
If you have a lot of straight runs why not use intermediate conduit for them and change to pvc when you need to.
 
danickstr said:
If you have a lot of straight runs why not use intermediate conduit for them and change to pvc when you need to.
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How would you bond IMC if its in between 2 PVC 45's? Forest green J-boxes and bond bushings?
 
chris kennedy said:
How would you bond IMC if its in between 2 PVC 45's? Forest green J-boxes and bond bushings?
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:D :D :D
PVC is the way to go here. Lot of trees to weave through. He (HO) called this evening and said it's a go. My EI gave me the OK as well. Heading out with a boatload Monday. HO also added a branch circuit run 125' to the sauna. Hope I have 10/3 UF at the shop and some one inch.
 
This is not my area of work, so the below is probably totally off the wall.

But what about using the heavy duty PVC coated MC cable (the stuff rated for sunlight exposure as well as direct burial). Laying it out on surface supported by a sand bed, and then next year simply pushing it into the trench?

-Jon
 
Jon makes an interesting observation. Few electrical installers discuss design issues on this forum, unless they are complaining about inspectors. Perhaps people don't like dealing with design when they become accustomed to relying on prints, customer specs, or materials provided by someone else?

If the savings in labor would be worth $5.37 per foot + freight Alcan’s MCJ
http://www.cable.alcan.com/alcancab...ding+Wire+Products/STABILOY+Type+MC+Cable.htm
is listed for Sun exposure and direct burial, but with 4-wire cables, the needed 2-wire + reduced Ground must be special ordered, requiring a minimum order quantity of 5000 feet.
http://www.cable.alcan.com/NR/rdonlyres/458D6E4E-935A-4B04-AC5A-3CFEEC450057/0/MC.pdf

For other cables, however, typical Sch-80 PVC does not seem permitted by NFPA 70 352.12(E) where the conductors can operate over 60c? Carlon makes a PVC conduit listed for 90c, but that is also a special order.
 
ramsy said:
For other cables, however, typical Sch-80 PVC does not seem permitted by NFPA 70 352.12(E) where the conductors can operate over 60c? Carlon makes a PVC conduit listed for 90c, but that is also a special order.
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Correction: PVC should good to 75?C, unless listed otherwise.

2006 UL White book: RIGID NONMETALLIC SCHEDULE 40 AND SCHEDULE 80 PVC CONDUIT (DZYR)
Unless marked for higher temperature, rigid nonmetallic conduit is intended for use with wire rated 75?C or less including where it is encased in concrete within buildings and where ambient temperature is 50?C or less. Where encased in concrete in trenches outside of buildings it is suitable for use with wires rated 90?C or less

2006 UL White book: REINFORCED THERMOSETTING RESIN CONDUIT (DZKT)
Reinforced thermosetting resin conduit has been investigated for use with conductors rated 90?C or less.
 
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