Flat or twisted cable for deep well pump

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cichyb

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So I bought 275 feet of twisted cable and now I'm hearing I screwed myself and should have bought flat because it will come loose and short out. Any input would be great. Can I just tape the heck out of it?
 

Boycedrilling

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When I started in the industry 30 years ago, the company I worked for had the following rule of thumb. If the pump was inside casing, we used twisted PVC submersible wire since it was less expensive. We used flat double jacketed only in open rock or uncased wells.

These days I use flat double jacketed for everything. I don't feel the cost savings is sufficient to carry two types of wire. I'm not interested in saving $50 on a five or ten thousand dollar job that I'm guaranteeing.

How often to tape the wire to the drop pipe? Some people tape it once per 20 or 21 ft length of drop pipe. Some tape it twice. If you're using poly pipe I would probably tape it at least every 10 feet or less. It will be interesting to see what the comments will be from other professionals.
 

cichyb

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When I started in the industry 30 years ago, the company I worked for had the following rule of thumb. If the pump was inside casing, we used twisted PVC submersible wire since it was less expensive. We used flat double jacketed only in open rock or uncased wells.

These days I use flat double jacketed for everything. I don't feel the cost savings is sufficient to carry two types of wire. I'm not interested in saving $50 on a five or ten thousand dollar job that I'm guaranteeing.

How often to tape the wire to the drop pipe? Some people tape it once per 20 or 21 ft length of drop pipe. Some tape it twice. If you're using poly pipe I would probably tape it at least every 10 feet or less. It will be interesting to see what the comments will be from other professionals.
Yes it's in a well casing.. and I already bought it ugh....
 

Valveman

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I like round jacketed cable better as you don't have to worry about keeping it flat. I use the regular THHN, black, underground burial cable. The same stuff I bury in the ditch, I run down the well also. It is not stamped "submersible pump cable", but it works great. I have used it from #12 to #0 on wells that are 50' or 2000' deep.

I don't like the twisted or the flat yellow parallel cable. The more you tape it to the pipe, the more places it will wear against the pipe. But the less you tape it, the more it slaps against the casing. However, any wire will chaff less when the pump cycles fewer times. :)
 

Reach4

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Yes it's in a well casing.. and I already bought it ugh....
When taping, leave a little slack for expansion and contraction differences. http://www.engineeringtoolbox.com/pipes-temperature-expansion-coefficients-d_48.html

To allow for 50 degrees F of temperature rise vs install temperature, that would mean 0.44 inches for 10 ft of poly drop pipe or 0.11 inches of slack for 10 ft of PVC. If it is going to always be cooler in the well than when you tape it, then no added slack would be needed.

Some additional slack may be needed for the poly to allow for relaxation of the pipe. I don't know what that amount should be.
 
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Craigpump

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I've been using stranded, flat parallel wire from Regency for 7 years. I like the way it lays against the pipe and tapes off nice and flat. However, it's a pain on poly pipe.

On stick pipe we tape above and below the coupling. Bigger wire like #8 we tape every 10'.
 

Texas Wellman

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Almost all mine is #12 sub cable but not double jacketed. It seems to last as long or longer than the pump. I tape on every joint just above the coupling. Most pumps are set 60-140 ft down ( or 63'-147' with galv joints).
 

Boycedrilling

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All the pumps I install are either on sch 40 galvanized or sch 120 PVC pipe. I do not use poly drop pipe ever. Most pumps I install need #10 wire or larger. Pulled a 20 hp set 300 ft on 2" galvanized this morning. Then moved the 10t pump truck to the next job. It will be a 460 volt 3 phase 10 hp, set 500 ft on 2" galvanized. These are both temporary test pumps for new community water systems. We run a 4 to 24 hr pump test and take water samples for bacteria, IOC's, VOC's and SOC's. We will be doing about a dozen new community systems for H2A farm worker housing this spring.

We can still install that 10 hp 460 volt motor on #10 wire. I use the 2" wide green 10 mil thick pipe wrap tape to attach the wire to the drop pipe, not 3/4" electrical tape. I usually tape the wire 5 ft below and 5 ft above each joint.

I've got a couple of 125 hp submersible test pumps. I'm using 4/0 wire with those. Tape isn't enough to support this wire. It gets strapped to the drop pipe every 10 ft with 3/4" stainless steel banding material.
 

MI Well Drilling

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Use what you bought and tape it every 10 feet. If you're worried about the wire you bought and it's not to far down use something to cover it with. I've seen people use old garden hose and tape it every 10 feet. Not very often but I've seen it.
 
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