Pulling wire in conduit?

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lovingHDTV

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May 25, 2007
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Round Rock, TX
My timer is wires with 220V and I need to add a 110v circuit. The conduit is 3/4 inch and has 3 12 gauge wires in it now.

There is plenty of room to add the two 14 gauge wires I need, but how do I pull the additional wires? There is no pull cord in the conduit at this time. I could try to run my snake through it, but I"m not sure that will work. Should I just pull out all the wires, then re-pull all 5 at the same time?

Anyone dealt with this before?

thanks,
dave
 
lovingHDTV said:
My timer is wires with 220V and I need to add a 110v circuit. The conduit is 3/4 inch and has 3 12 gauge wires in it now...no pull cord in the conduit at this time...
Click to expand...
Most electricians don't leave "pull cords" in conduit.
Do you have 3-12 STFF (solid/stranded?) wires in the conduit?
Is the conduit plastic or steel?
How many bends (90 and 45) are there?
Can you shut off the 240V (you would want to anyway :!: ) and use the existing ground wire in the conduit to pull an new ground wire AND the 3 new 12 GA wires (4 wires total) to the new location?
-That way you could put in a 20A receptacle circuit and all wiring in the conduit will handle 20A loads.
If you've never done anything like this PLEASE have an electrician do it.
 
3 - 12 gauge solid THHN wires
plastic 3/4" conduit
The conduit is buried but there has to be at lease 1 45 and two 90's. It goes from the breaker panel to the wiring junction box by the equipment pad. I will be turning off the power, probably just turn off the entire sub-panel before doing any of this work.

My plan is to add a 15A breaker to the panel, run a new common and hot for the 15a 110v circuit. I'm not opposed to running a 20A circuit with 12 gauge wires, but just thought it way over kill for my 370mA pump motor, but 15A is way overkill also :)

Using the ground to pull through the new wires was something I had thought about.

I'm kind of confused why you say pull pull 3 wires for the circuit and the new ground? Wouldn't that be two wires for the new circuit and the new ground for a total of 3 wires?

I've no issues with the wiring portion, I've done lots of wiring before. Just nothing in conduits.

thanks
dave
 
lovingHDTV said:
3-12 gauge THHN solid wires, plastic 3/4" conduit...at lease 1 45 and two 90's...from the breaker panel to the wiring junction box by the equipment pad....plan to add a 15A breaker to the panel, run a new common and hot for the 15a 110v circuit. I'm not opposed to running a 20A circuit with 12 gauge wires, but just thought it way over kill for my 370mA pump motor, but 15A is way overkill also...
...pull pull 3 wires for the circuit and the new ground? Wouldn't that be two wires for the new circuit and the new ground for a total of 3 wires?
Click to expand...
370mA pump motor? Is this for a small fountain pump?
If you are talking about 370mA it's not really going to matter; both 15A and 20A are overkill. Either will require Hot, Neutral, Ground wires for the new circuit PLUS the new ground to replace the one that you are pulling out.

If I'm going to pull wires in a conduit that already has 20A circuits in it (#12 wire) I try to match what's already there. Rember that you are going to need a GFI receptacle and water-tight cover too.

How close is this to the pool?
 
The pump is a very small peristaltic pump that I will be using to inject acid into the pool. I thought about just wiring it to one leg of the 220V and the ground, but that is not safe to do so figured I'd just pull a new 15A 110V circuit.

So you are saying I should have separate grounds, one for each circuit. I guess that makes sense, I can do that. I figured they were both going from the same breaker panel to the same wiring junction box so I would just use one ground for the two circuit.

Who knows what else I could add out there, like a light? Would be nice to have a light out there instead of using a flashlight after dark.

The equipment pad is about 35 feet from the pool.

I have a waterproof enclosure that I'll be wiring everything up in that I will mount on the side of the house.

thanks
dave
 
lovingHDTV said:
The pump is a very small peristaltic pump that I will be using to inject acid into the pool. I thought about just wiring it to one leg of the 220V and the ground, but that is not safe to do so figured I'd just pull a new 15A 110V circuit.

So you are saying I should have separate grounds, one for each circuit. I guess that makes sense, I can do that. I figured they were both going from the same breaker panel to the same wiring junction box so I would just use one ground for the two circuit.

Who knows what else I could add out there, like a light? Would be nice to have a light out there instead of using a flashlight after dark.

The equipment pad is about 35 feet from the pool.

I have a waterproof enclosure that I'll be wiring everything up in that I will mount on the side of the house.

thanks
dave
Click to expand...

Dave
When I wired up my chlorine pump, I just used one leg of a 220V pump wire, and a neutral. Since you need neutral, you can pull a 110V wire though.

In the end, I think you would need 5 wires
220V #1
220V #2
ground
110V
neutral

You can tie the same ground to the 110V and 220V circuits.

I would think you could just tie a string to one of the wires, and then pull the string through. Then, use the string to pull the new wires, but also keep pulling a new string though.

When I was pulling wires for my HT setup, I found some "wire lubricant". I think I bought it from Home Depot, but then later bought some better stuff from the internet. Without the lubricant, I couldn't pull the wires though, but THHN wire is already slick, so you might not need it.

Randy
 
My father is an electrician and he did the same thing for me that Randy described. I have 220 where I had an above ground spa and he used that sub panel to add a 110 outlet in that area. I don't know the details but I do know we did not run any new wires from the main panel.
 
randytsuch said:
Who knows what else I could add out there, like a light? Would be nice to have a light out there instead of using a flashlight after dark.
Click to expand...
How about installing a pole lamp? The hollow aluminum poles are about $75 and the fixtures are $25 (or as much as you want to spend). You can add a receptacle and photocell for the light that mount directly on the pole for about $15 each. I installed one last year and it's nice: no switch necessary and you don't have to worry about turning the light off and on. Vary the wattage of the bulb and you vary the brightness of the area. 8)

I'd use lubricant even with the THHN wire. It's cheap and makes the job easier :goodjob: .

BTW: I'm a firm believer in separate ground wires, just joined together in the sub-panel.
 
Just got back from HD with:

1 15A GFCI breaker
500 ft stranded 14 gauge thhn wire (black, I'll use color tape to mark the common, pulled the panel off the breaker box and the original wire is stranded, not solid like I thought)
8 ft of 1/2" LQ PVC conduit with fittings
KwikSet masonry anchors for my junction box
poly twine to pull wires

$~90 for it all

I've heard you can use Dawn dishsoap as lubricant good, bad?

Let the fun begin!

dave
 
You don't want to use dish soap. It will work for now, but over time it will harden up like glue and you will never get anything into or out of that conduit ever again.

You can pick up the correct kind of lubricant in the electrical department at Home Depot or Lowes inexpensively.
 

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Second Jason's comment. Get a good synthetic wax-based wire pulling lubricant.
If you use soap, you'll never pull wire through that conduit again.

If you have a plastic grocery bag and a shop vac, you can get that pull cord through the conduit in short order. Cut a corner off a grocery bag, tie the cord to it, and stuff it into one end of the pipe. Fire up the shop vac on the other end, and you should get the cord through almost instantly.
 
Thought I would report back.

I pulled all the wires today with the help of my 12 year old son. I ended up pulling the ground wire out with a string attached to it. Once out I used it to measure two more new wires (hot and common) for the 110v circuit. I then pulled everything, including a new string back through the conduit. I didn't even need any of the wire lube I bought. It was very easy to do.

Took about another 30 minutes to get everything put in place and wired up. Now I have a 110v GFCI protected circuit pulled to my equipment pad hooked to the pump relay on my AutoPilot.

Thanks to everyone for their help and suggestions I'm very pleased with the results.

dave
 
If you have three wires providing 220 in the conduit, my guess is they are red, black, and green wires. If so, you can get 120 between either the red and green or the black and green. No need to pull new wires for 110. Check it out with a simple volt/ohm meter which you can buy at any hardware store for 10 or 15 bucks.

Robolt
 
you can get 120 between either the red and green or the black and green.
Click to expand...
You definitely do NOT want to do that.

The green wire would be a ground/bonding wire, and designated specifically as NOT a current-carrying conductor for safety purposes.

You need a neutral conductor (white) for connection as 120 volts. So if there isn't one already, you'd still need to pull a wire.

The neutral and ground may (in theory, but often not in practice) be at the same potential, they should not be connected together except at the main feed point, and the green should NEVER be used as a current-carrying conductor.
 
I'm pretty sure that the two circuits can share a common ground, as they share a common main feed. It would need to be as large as the largest conductor in the conduit or raceway, and must bond to all metal parts.
It's always worth consulting the AHJ (Authority Having Jurisdiction) in your specific case.
 
JasonLion said:
You can not share a ground if you are using GFCI circuit breakers, the breakers will trip all the time if you do.
Click to expand...

Its the common that cannot be shared. Per the GFCI instruction manual:

"This arc-fault detection device is not designed or intended for use on circuits in which the neutral conductor is shared with other circuits. The circuit breaker will nuisance trip in "shared neutral" circuits."

Basically a GFCI compares the current flow between the hot and common legs of the circuit. If they differ then it trips. The idea being if the current is not flowing back to the breaker it is going somewhere else which is not a good thing. If the common is shared, then additional current from the shared device will flow back through the common and will cause the breaker to "nuisance trip".

The ground should never carry any current.

dave

Edit:
OK these guys explain it better than me:

http://home.howstuffworks.com/question117.htm
 
Seems a solution is already done...For something this small I would of just bought a small transformer and had a circuit off the 220V run the 110V. Google 220V to 110v transformer, no wires to re-run. They are almost three times as much but you can even get one with an outlet already in it.

http://www.nextag.com/220v-to-110v-tran ... 5503850FD8


If you elect to pull new wires, it can be kinda tough with wires this big but you just tie together (interlock ground and put electrical tape around it) the new wire with the old. They make wire lube if you think its needed. As you pull the old one out the new is being fed through. No double wires needed to feed, no fishtape, no string, just help to work both ends.
 

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