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Joined: Jul 2017
Posts: 10
Y
Member
Drawings show 42 inch trench with HDPE turning up into primary side of transformer Pad.
As Carlon shows 30 X Conduit size radius as min. bending allowed I think factory 90's are required
Anyone have experience with this???
Yooperup

Last edited by Yooperup; 07/11/17 08:06 AM. Reason: Mistake
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Joined: Jul 2004
Posts: 9,677
Likes: 9
G
Member
As long as the bends do not decrease the ID of the raceway and do not use a radius less than the manufacturer requires you will be OK I am not sure how you would do this without some sort of mandrel tho. This plastic pipe gets pretty droopy if you just route the exhaust from the truck through it wink

Quote
353.24 Bends - How Made. Bends shall be so made that
the conduit will not be damaged and the internal diameter
of the conduit will not be effectively reduced. Bends shall
be permitted to be made manually without auxiliary equipment,
and the radius of the curve to the centerline of such
bends shall not be less than shown in Table 354.24. For
conduits of metric designators 129 and 155 (trade sizes 5
and 6) the allowable radii of bends shall be in accordance
with specifications provided by the manufacturer


Greg Fretwell
Joined: Jul 2017
Posts: 10
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Pipe, Conduit and Innerduct for Underground Utilities

There are a number of conduit and innerduct options available for underground utilities applications. Choosing the right pipe can provide significant savings, both in material and labor costs. Below are several types of underground and electrical conduit, with the advantages and disadvantages of each, so you can make the best choice for your application.
HDPE Pipe
High density polyethylene or HDPE pipe is a strong, light weight and flexible product that can be used as conduit (duct) or innerduct. Both smooth and corrugated HDPE varieties are available. HDPE is often used in electrical, utilities and telecommunications to protect underground cables and lines from impact, environment, weather, rodents, and other corrosive conditions.
Advantages:
• HDPE pipe easily bends around obstacles like roadways or rivers. This allows trenchless installation of underground lines and provides a significant cost savings.

• HDPE pipes are flexible and can be bent to a minimum bending radius of 30 times the pipe's outside diameter

• HDPE pipe joints can be heat fused together to form a leak-free and extremely strong joint.
• The flexibility of HDPE pipe makes it ideal for areas that are prone to earthquakes.
• Service life of HDPE pipe can be 50+ years, keeping replacement costs low.
• HDPE pipe is corrosion, abrasion and tuberculation resistant.
• More impact resistant than PVC pipe, especially in conditions with low temperatures.
• Lower cost and lighter weight than metal pipes.
• Available in longer lengths than pvc, allowing installation of longer lines with less jointing.
Disadvantages:
• HDPE pipe is shipped on rolls that may need to be returned to the manufacturer after use.
• Ovalizing of the pipe can occur from being wrapped on the rolls.

Joined: Jul 2017
Posts: 10
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Member
Point is you cannot turn a 90 up in 42 inches. I say Factory 90's are required for a correct job install.
Otherwise you come into the transformer pad on a angle.

Joined: Jul 2004
Posts: 9,677
Likes: 9
G
Member
You are right. I didn't do the math. Good catch.


Greg Fretwell
Joined: Jul 2004
Posts: 9,677
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G
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FPL has a big HDPE job going up at the end of my street. If I can get there before they back fill i will stop by and see how they are getting up the poles.


Greg Fretwell
Joined: Jul 2017
Posts: 10
Y
Member
Remember this is 6 inch. I've got some photos of one done with 6 inch they came in on the side .'
Could not make the bend.

Joined: Apr 2002
Posts: 7,288
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Greg:

Does FPL follow the mfg. instructions??

Pot:

Anyone suggest increasing the trench depth to accommodate the sweeps??

I ask because extended radius sweeps are required by our POCO, and by various Telco/Cable etc. utilities. The solution mostly is 'dig deeper'



John
Joined: Jul 2017
Posts: 10
Y
Member
They make adapters to put long sweep 90's on which I suggested.
The designer told me they do it all the time in 42 inches.
But I've found out can't be done. This raceway is for 13.8 HV which in itself requires larger
bend for the cable. Just wondered how other have handled something like this.
Thanks for your time guys. Always nice to get others input.

Joined: Jul 2004
Posts: 9,677
Likes: 9
G
Member
As I said earlier the only way I can see this without kinking the raceway is to heat it and bend it around a mandrel.
Granted this usually happens with PVC.
I looked at the job going on at the end of my street and they are just brute forcing the bends. This is utility work by contractors so I doubt anyone is really inspecting it. The wire was already in the pipe when they make that final turn up. That is not unusual for utility contractors. I watched them running service laterals a while ago and they were threading the wire in the joints of pipe as they went.


Greg Fretwell
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