I have a partially completed project, the contractor backed out, after installing the conduit. Now I have a 2 1/8 i.d. conduit running app.
250' underground with a nylon cord run through it to pull wires. The original plan was to run 3 strands of 2.0 copper, which is probably excessive for the intended load. I intended to pick up the project myself, I have at least advanced amateur wiring skills, but went to Lowes and priced the job, and found that 3.0 copper was actually cheaper per ft. Can 3 strands of 3.0 be successfully pulled through that conduit? Any tips / procedures?
Without any idea what the intended use for the feeder is, it's impossible to give advise, however if its a clean straight shot, three 3\\0 conductors will fit. Just make sure you don't try pulling it with the nylon strand
Without any idea what the intended use for the feeder is, it's impossible to
The intended use is to power a workshop with a 4 post lift, air compressor, welding equipment, and a wood shop (mostly 220v). It is a one person shop generally, so it would be unusual to have more than one load at a time, though my so has welded while I sanded or lifted a car, and with the present hopelessly inadequate feed it browned out the entire shop. I had every intention of using the nylon to pull the wire, glad you mention that, what should be used? I have pulled cars with that stuff, I thought it was bullet proof.
If it's strong enough to pull a car it's fine. Usually a thin nylon strand is blown into the pipe and a poly rope is tied to that for pulling. Is this a new service or a feeder from an existing panel. If it's a feeder from an existing panel, you should pull a ground wire along with the feeder. I can't believe with copper prices as high as they are, that anyone is selling 3/0 cheaper than 2/0
You should be able to pull up to five THHN or THWN #3/0 conductor in a 2" conduit by code. I would also use pulling lube (also known as soap) which you could buy at Lowes as well.
Eric As someone has already suggested you will want an Equipment Grounding Conductor (EGC) in that feeder unless it is supplied from a separate service with it's own meter directly from the local power company. If that feeder will share a service with any other building then you really want an EGC in that feeder. The reason for the concern is that if a neutral connection ever failed the current it carries would try to return to the source via any other grounded conductive pathway. Those can include telephone lines, cable jackets, intercom lines, security wiring, metallic piping systems, and the local earth itself. Such stray currents can cause electric shock, erratic behavior in pets, pour production in dairy cattle, destruction of metallic systems, and under some circumstances fire. The practice of running feeders without EGCs will no longer be allowed under the next edition of the US National Electric Code.
On a separate subject if the trench has not been fully back filled you should take this opportunity to install a one inch low voltage raceway so that you can run communications, alarm, and video wiring between the two buildings at a later date.
-- Tom Horne
"This alternating Current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison
Thanks for that info!! I wondered why as the third big wire was after all a ground, why one would need a dedicated ground wire besides. How big does it need to be? If it needs to be as big as the others, it would add significantly to the cost of the project. The conduit has been in the ground for a little over 2 years, but I did run a 2 conductor direct burial communications wire when the trench was open.
To answer that question I need to know the size of the Over Current Protective Device (OCPD) that will protect the feeder. IOW what size fuse or circuit breaker will control the current to that feeder. The size of the OCPD governs the size of the Equipment Grounding Conductor.
You can use the nylon as long as it's big enough (ie too strong to break with the expected pulling force...... 3/16 or 1/4 would be fine but a little hard on your hands) One drawback of nylon is that it is kinda stretchy. If you have to but a larger rope because the cord is too small you might consider a larger nylon rope.....useful in the future. Or if it's a one shaot use get cheaper material & just toss it)
Your run is pretty long.....I would suggest the use of real wire pulling lube and most importantly.......have a helper push the wire as you pull it (or vice versa, if the helper is stronger)
You can use the nylon as long as it's big enough (ie too strong to break with the expected pulling force...... 3/16 or 1/4 would be fine but a little hard on your hands) One drawback of nylon is that it is kinda stretchy. If you have to but a larger rope because the cord is too small you might consider a larger nylon rope.....useful in the future. Or if it's a one shot use get cheaper material & just toss it)
Your run is pretty long.....I would suggest the use of real wire pulling lube and most importantly.......have a helper push the wire as you pull it (or vice versa, if the helper is stronger)
Tom you've lost me, the electrician who originally planed the job planed to put a second main directly below the primary main to get the tap for the sub panel as double lugging the meter isn't permitted Wouldn't actual grounds at both ends achieve the same result? The breaker in the 1st panel will probably be a 150, to stay below the value of the main, then a 100 in the sub panel in the shop to stay below that, then 50-60 as a maximum for the individual circuits. I really don't have many high draw tools, the welder and the planer both pull a bunch (not a technical term), but they are seldom used, then again, when they are it is usually intense.
I hadn't thought about the helper angle, but agree that it would work, I've see that push / pulling romex around corners where you drill from both sides (happens sometimes in remodeling) and a strong helper makes all the difference. I have a big roll of 1/2" tight mesh nylon, probably enough to double up over the distance. I was considering pulling with the bucket loader as it would be a vertical pull, only danger would be no feel for snags which could lead to breaking the pulling lines. I have about a quart of wire pulling lube, & will get more if needed (suggested).
By current NEC rules, you can install ground rods at the remote building to ground the system, but only if there are no metallic conductors of any kind linking the two buildings together, such as water pipes, telephone cables, metal conduit etc.
It is not really "legal" but the power company usually trenches down to the elbow, cuts it off and pulls the triplex straight in when they run long service laterals. They put the elbows back over the wire. The "legal" way to do this is with an LB. You can take the cover off, pull the cable down the "B" side, connected to the lateral and shove the wire up the riser, replace cover. A couple of 90s makes a long pull virtually an impossible pull without damaging something. Having the rope cut through a 90 is very common if it is not metal. That will bind up and stop the pull.
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