Running ditch for conduit


I am running a ditch about 200 feet from my house to run power to my
building. I see no way from making turns because I have to avoid
septic tank, etc. I will use pvc. Is it best to run gently turns
minimizing the sharpness of the angle or just do 90's and the
appropriate 90 degree fitting? WIll I be able to pull wire at a later
date if I do the 90's?
Reply to
stryped
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That is why they make 45 degree bends! Why can't you put the wire in the conduit as you go? Always include a pull rope for later additions.
If you have to avoid the septic tank, then you also need to avoid the drain-field from the septic tank. Can you do that?
Paul
Reply to
co_farmer
You can buy smaller bends than 90 and 45. Use a large weed burner to heat the pipe VERY SLOWLY over a large area to make gradual sweeping bends. Even though most guys will tell you otherwise, some times it is a real bitch to get a sizeable cable through a conduit once it has been buried. I am currently doing the same thing, with 2.5" PVC conduit (it was free) and 2/0 aluminum direct bury cable. I have been told that it is easy to pull this through, but I am going to pass the pipe onto the cable, glue it, let it dry, and then bury the assembled pipe rather than burying it and then pulling it. Sometimes it pulls easy, sometimes it don't. I'm not going to find out, but put the wire in there with the pipe.
Steve
Reply to
SteveB
Is it best to run gently turns
Stryped
First of all use sweeps instead of 90 degree fittings. Electrical PVC will bend some so plan your run around and with the routing some more. At the ends use sweeps again to terminate the run. Also LBs. Fittings with removeable covers. And install pull wires or a rope as you go along. It also might be prudent to put an inline LB in the middle of the run. And also pull in something for a phone, cable TV, computer and remote control of electrical things. An additional 1" conduit. With a pull wire or rope. Be sure to include a ground wire and neutral wire. You did not mention amps and phases so I have not included any of this information. A 200 foot run will have to include wire sizing for distance and loading. The remote or sub panel will have the neutral buss isolated from ground. A ground rod at the end will be prudent if not required by the AHJ,
Write more with amp and voltage information. remember the sub panel breaker in the source will have sizing specs separate from what the breaker sizing is in the feeding panel.
Bob AZ
Reply to
Bob AZ
Well, I assume you will be following the relevant standards - here in OZ at any rate its orange power yellow gas white telecoms.
and there is an associated vertical clearance between each pipe if your putting them in the same trench. Oh, and lay a tracer wire near the top - means you can locate the (plastic) pipe years later when you cant remember where the trench runs,,,,
Gradual, sweeping bends are fine, else use pre-formed bends (its what there made for) - run a draw wire in the pipe as you lay it, and ALWAYS pull in a new draw wire with each new length of cable.
My experience of faults in this area has been that blockages occur when 1.The pipe is crushed by backfill 2 There are voids left under a section of pipe, so its distorted by backfill. Throw crushed rock/sand under these before you backfill. 3. Poor gluing of joints - this last one can be a killer as it is exacerbated by the above 2.
Do not skimp on the process, it will be a real bitch to fix years later if something goes wrong.
Andrew VK3BFA.
Reply to
Andrew VK3BFA
This will be a 200-250 foot run form my house to the detatched garage with s few bends because I have to avoid my septic tank and field lines.
It will be 100 amp run. Not sure yet what wire size I need. I am going two ground rods in the trench as well as a ground from my house panel to this sub panel.
Reply to
stryped
Stryped
With a 100 amp run you will need to carefully check your service panel for the maximun circuit breaker size for a sub panel. This will also effect the subpanel size. Also be aware that one can use a larger panel for a subpanel to gain more circuit breaker spaces. e.g. a 125 amp subpanel but fed with a 60 amp breaker. Even with a 200 amp panel the limit on CB sizes for a sub panel might not be 100 amp. Mine is this way. I have a 200 amp service panel with the meter in the same enclosure. Maximize the number of CB spaces by installing a larger size subpanel than 100 amp. Then you will be able to maximize the number of 220 volt loads. Like for power tools such as a lathe and milling machine. And for the AC if this is part of your plans.
A 100 amp 200+ foot run will probably require a 2 size increase in wire size. e.g. From # 1 wire to 00. Don't use aluminum. Less expensive now but the future will cost you a bundle. As I frequently say Pound Stupid - Future Smart.
There is or should be a ground bar or two at your service panel. Two at the sub panel location would also be prudent. Be sure to space them as the NEC requires. Also the ground wire should be without splices as it runs from one ground rod to another and onto the ground buss in the panel. You might want to run in a separate 1/2" conduit for the ground wire from the ground rods. I have used a conduit sized LB in the feed from the service panel to provide an entrance for the ground wire. Again do not connect the neutral buss to the ground buss.
Bob AZ
Reply to
Bob AZ
"Bob AZ" wrote
Say what? For a 200' run of 2/0 aluminum direct bury, it's $350. For three runs of #3 copper, and a #6 ground, it's nearly $900. I think I got the sizes correct, but I don't have that slip of paper in front of me, and I forget things easy. I do remember the prices clearly, though. The prices are for wiring that will carry comparable loads. I'm putting it in conduit, but am still using direct bury aluminum, as then I don't have to trench part of the way which is in caliche.
My friend is a journeyman union electrician. He told me for a shop my size, aluminum would be fine. Now, I'm not going to be running big welders, but for what I want it for, it is oversized. He has done a lot of work for me, and is highly trained in high voltage work, and even underwater work doing work on the fountains at various Las Vegas casinos. I trust what he says.
Why in the world would I want to spend $900 when $350 will do? What's so bad about aluminum in the future?
Steve
Reply to
SteveB
=EF=BF=BDFor three
=EF=BF=BDThe prices
With aluminum you will have to go a guage bigger. So 00 for copper and 000 for aluminum. I am not sure about the ground size. 6 maybe and possibility 4.
You will have to trench. Direct burial or not. Or run overhead. Also you will have to trench big enough to cover whatever with sand. Probably 12". Is a permit part of your plans? I am well acquainted with caliche having lived with it for 65 years.
Aluminum wire has a bad habit of failing when buried and in contact with anything but aluminum. The power company used to use it here but they are well equipped to deal with it. You and I are not. I have not seen any use of it in the last 20 years. Does Home Depot still carry it?
Bob AZ
Reply to
Bob AZ
"Bob AZ" wrote
With aluminum you will have to go a guage bigger. So 00 for copper and 000 for aluminum. I am not sure about the ground size. 6 maybe and possibility 4.
Yes. as statec, 2/0 instead of #3.
You will have to trench. Direct burial or not. Or run overhead. Also you will have to trench big enough to cover whatever with sand. Probably 12". Is a permit part of your plans? I am well acquainted with caliche having lived with it for 65 years.
No permit.
Aluminum wire has a bad habit of failing when buried and in contact with anything but aluminum. The power company used to use it here but they are well equipped to deal with it. You and I are not. I have not seen any use of it in the last 20 years. Does Home Depot still carry it?
It will be in 2.5" PVC pipe except for the little bit in direct bury. HD, no. From a supply house.
Bob AZ
Reply to
SteveB
Aluminum wire has a bad habit of failing quickly when installed by lazy idiots. When installed by competent tradesmen it works fine for decades. Run in PVC conduit, buried in sand and with cement strips planked on top to protect it it will work well. Do understand how to deal with freezing and condensation in the conduit.
Reply to
Neil

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