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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Pulling large wire in conduit
"DaveC" wrote in message news.net... Four AWG #1 conductors in 2-1/2 inch EMT. 50 ft of conduit, four 90 deg. elbows. Is this combination reasonable to pull with some lubricant? Or should I plan some "pull boxes" in this run? Thanks, -- Please, no "Go Google this" replies. I wouldn't ask a question here if I hadn't done that already. DaveC This is an invalid return address Please reply in the news group No code book in front of me tonight but I think your conduit is too small for four # 1 wires for normal power feeds. It's not just wire size that counts you have to consider current in conductor and heating. Four 90 degree bends (electricial sweeps) are the limit I think. Do you need to use lubricant to pull, If I am helping you will use lubricant, if you pull it's your choice. I would use a steel cable as a fish tape and a comealong to pull it. Hugh |
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Pulling large wire in conduit
DaveC wrote:
Thus spake Hugh Prescott: No code book in front of me tonight but I think your conduit is too small for four # 1 wires for normal power feeds. It's not just wire size that counts you have to consider current in conductor and heating. Four 90 degree bends (electricial sweeps) are the limit I think. Do you need to use lubricant to pull, If I am helping you will use lubricant, if you pull it's your choice. I would use a steel cable as a fish tape and a comealong to pull it. I ended up using 2 90 degree sweeps and two inspection boxes (90's as well). Used fish tape to pull nylon rope which was used to pull the wires. Man, is it hard work. It's not a big job, but no come-along, just two inexperienced guys huffing and puffing. An inspection box is an asymmetric item. Pulling the wires into the box in the longitudinal direction was relatively easy; feeding them back into the "exit" that is 90 degrees to the body was problematic (especially the last 18 inches, or so). How does one do that last bit of wire so that you don't end up with a twisted knot of wires that won't fit in the box? 1-1/2 EMT is sufficient for four (one is ground) #1 conductors (NEC tables referenced). Thanks for all your help, guys. Mission accomplished. it's no problem putting them back in , you simply have the Access Elbow loose, side the wires through and then in the other pipe. after that you just sit the elbow on the pipe ends and position the pipe with wires already inside. -- Real Programmers Do things like this. http://webpages.charter.net/jamie_5 |
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Pulling large wire in conduit
DaveC wrote:
I ended up using 2 90 degree sweeps and two inspection boxes (90's as well). Used fish tape to pull nylon rope which was used to pull the wires. Man, is it hard work. It's not a big job, but no come-along, just two inexperienced guys huffing and puffing. An inspection box is an asymmetric item. Pulling the wires into the box in the longitudinal direction was relatively easy; feeding them back into the "exit" that is 90 degrees to the body was problematic (especially the last 18 inches, or so). How does one do that last bit of wire so that you don't end up with a twisted knot of wires that won't fit in the box? It is easiest to start at a elbow fitting in the middle and feed wires to one end. In any case, for the otherside of the elbow bunch the wires so they remain in the same orientation to each other from the elbow to the loose wire ends and feed the wire into the elbow in that orientation. That prevents 'knots'. Assuming an LB fitting where one entry to the elbow is out the back, to pull the wires tight into the fitting, pull the wires out through the back as the last step. As the wires get almost tight, pick the wire that will wind up furthest back in the fitting and bend it at 90 degrees at the location it will have when the wires are tight. Pull just that wire out through the back until it is tight. Repeat for the remainng wire that will be furthest back in the fitting.... If the back-entry of an elbow connects to the back-entry of another elbow it is a real PITA. If you had used all sweeps as John Ray suggested think of the fun you would have avoided. Electricians have nifty motor drive wire pullers to make pulls like this easy. bud-- |
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Pulling large wire in conduit
DaveC wrote:
Thus spake Bud--: If you had used all sweeps as John Ray suggested think of the fun you would have avoided. Tried sweeps originally. Couldn't pull the wire. Changed to L's, and each pull was do-able. Didn't know about keeping the wires parallel (no cross-overs) which would have made the original attempt OK, probably. I you mean cross-overs in the pipe, they can make a pull extremely hard. In some cases could also probably damage the insulation. Next time (!) I'm better armed with know-how. We get too soon old and too late smart. bud-- |
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Pulling large wire in conduit
DaveC wrote:
I can picture how to set up the wires (separate loops on the floor) for feeding in the initial pull. This will avoid cross-overs. But if you need to do more than one pull (via inspection L's), how do you avoid a similar tangle in the successive pulls? Is this automatically avoided by making your first pull organized? If you are using cut lengths of wire on the initial pull, as SQLit said lay the wire out straight on the floor. Someone feeds the wire in maintaining an 'orientation'. If I was pulling out of an elbow then feeding back in the other side, I would usually pull out enough wire for the rest of the run then feed it into the other side of the elbow. It may be easier if the wires are taped periodically in the right 'orientation' as they are pulled out of the elbow (keeps the 'orientation' and is less mess on the floor). It is typically easiest to feed wire into the back entry of an elbow. If the pulling rope stays connected to the wire (that is the 'orientation' stays the same at the end of wires) you probably can just feed the wires into the other side of the elbow but you have to get the 'rotation' of the wire bundle right (or close). Correct the 'rotation' as you pull the wires so when the wires are tight at the elbow the wire that is at the back of the elbow is the same coming in and going out. Especially if you are using pulling lubricant the floor has to be very clean. If I was starting in the center and pulling both ways, after pulling one side, I might start at the elbow and temporarily tape the wires in the right 'orientation' every 3' or so. Then attach the pulling rope with the wires in the right 'orientation'. Feed the wires in the other side, preferrably the back side, as above. But remove the tape first so 1 wire can be pulled at a time to get the wires tight into the elbow as described before. bud-- |
#6
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Pulling large wire in conduit
DaveC wrote:
Thus spake Bud--: If you had used all sweeps as John Ray suggested think of the fun you would have avoided. Tried sweeps originally. Couldn't pull the wire. Changed to L's, and each pull was do-able. Didn't know about keeping the wires parallel (no cross-overs) which would have made the original attempt OK, probably. Next time (!) I'm better armed with know-how. Electricians have nifty motor drive wire pullers to make pulls like this easy. Rentable? Will consider that next time... Thanks, Actually what you actually did is probably better; more hassle but less damage to the conductors (insulation). -- JosephKK |
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