Pulling Shielded Cable thru 1/2" rigid conduit

[E30bimmer]

I've decided to go with electric heat, a Northern Tool blower mounted unit that requires 240v. My garage is detached, 25 ft from house and has 110v already run.

Friend who is a former electrician said maybe we could pull more wire thru and not have to trench the 25. So, I just went out and checked the first outlet box and found shielded cable thru 1/2" conduit.

Is it possible to pull the old shielded cable out and run new for the 25' distance from house to garage?

Anyone ever do this before?

Thanks,
Trent

 

[Shiftless]

How many bends?

Let's wait for some sparkles to respond ...

I've never done it but based on my limited amateur experience pulling wires through 1/2 inch conduit, I would bet against it. Maybe with a winch or come along?

 

[Marctrees]

If it's electric heater of any decent size, , 1/2" will be too small.

Legally, and realistically both.

You already said 240, but we also need the Amps to determine wire and conduit size.

If it's not a big one, like needing only #10, or even #8 THHN, possibly you could sneak by.

With nothing else in that conduit of course.

Get those specs posted, THEN a real Sparky will give you answer.

Just a link to your chosen heater should do it.

And figure on using your old cable as the puller.

I will add, you may need someone w conduit pulling experience to get it done.

Sometimes, not as simple as one may think, dealing w tight pulls, tying on correctly, and often using wire pulling lube. Marc

 

[racingtadpole]

If my understanding is correct, 1/2" conduit is 1/2" ID. Being only 1/2" you will probably find you cant even pull the old cable out because the conduit was fed onto the cable as it was laid. If you do manage to pull the cable out with a draw string attached, it wont be a very big string, which will make it difficult to pull a larger cable in with. And if it was fed over the cable as it was laid, it may very well have right angle bends instead of swept elbows...

No idea what the digging will be like at your property, but for 25' I would pretty much guarantee that it will be easier than messing with your old conduit.

I would put in a much larger conduit, and also lay a capped spare with a draw rope inside the same trench.

Of course I'm not an American electrician, so take it with a pinch of salt

 

[LS6 Tommy]

If my understanding is correct, 1/2" conduit is 1/2" ID. Being only 1/2" you will probably find you cant even pull the old cable out because the conduit was fed onto the cable as it was laid. If you do manage to pull the cable out with a draw string attached, it wont be a very big string, which will make it difficult to pull a larger cable in with. And if it was fed over the cable as it was laid, it may very well have right angle bends instead of swept elbows...

Of course I'm not an American electrician, so take it with a pinch of salt

It's a code violation to pull the wire as you assemble the conduit. The conduit has to be assembled first, then the cable pulled. Of course, that doesn't mean the job was originally done to code.

If what the OP means by "shielded cable" is some kind of data line, it should be simple to tie a pull line to it and remove the old cable and get the new pull line ine. That being said, 1/2" is not going to be receptive to pulling any real heavy lines.

Tommy

 

[James-W]

It's just a suggestion, I know you just want to run the wiring for the heater, but if I were you I would consider some other options. Since it is only 25 ft you could rent one of those trench digging machines and be done digging a new trench in a fairly short period of time. Then you could run more than one conduit, one for the electrical line and if you want, run a conduit for cable TV and a Cat-6 cable for Internet. You could even run wiring for a home phone and/or an intercom.

 

[Bert_]

Everybody is assuming that the run is all in conduit. It sounds like the wire is UF and I'm not sure OP has checked it out enough to be sure.

If you can move the wire you could try to pull in some #8's and set a 50A sub-panel in the garage. Of course that's assuming it's something like a 5kw heater anything bigger and it doesn't leave much room to run power tools.

If none of our suggestions work out 25' really isn't very far to dig. At 25' forget a trencher just get out your spade.

 

[600SL]

Everybody is assuming that the run is all in conduit. It sounds like the wire is UF and I'm not sure OP has checked it out enough to be sure.

If you can move the wire you could try to pull in some #8's and set a 50A sub-panel in the garage. Of course that's assuming it's something like a 5kw heater anything bigger and it doesn't leave much room to run power tools.

If none of our suggestions work out 25' really isn't very far to dig. At 25' forget a trencher just get out your spade.

I believe he will need to pull a ground. 3 #8 and 1 #10 will not go into 1/2".

 

[James-W]

Everybody is assuming that the run is all in conduit. It sounds like the wire is UF and I'm not sure OP has checked it out enough to be sure.

If you can move the wire you could try to pull in some #8's and set a 50A sub-panel in the garage. Of course that's assuming it's something like a 5kw heater anything bigger and it doesn't leave much room to run power tools.

If none of our suggestions work out 25' really isn't very far to dig. At 25' forget a trencher just get out your spade.

Not trying to be a jerk, but the thread title is "Pulling Shielded Cable thru 1/2" rigid conduit" so just what else are we supposed to think?

 

[Bert_]

Not trying to be a jerk, but the thread title is "Pulling Shielded Cable thru 1/2" rigid conduit" so just what else are we supposed to think?

I guess it sounds like his shielded cable is UF and he hasn't tried to pull it yet. I was just suggesting that it might not be ran in conduit the whole way. The rigid could just be a sleeve where the wire emerges. If he hasn't checked into it very far he might not know for sure.

I'm not trying to say it's the only possibility, just one that had not been mentioned yet. I also gave input that could be helpful if the pipe IS ran the whole way.

I believe he will need to pull a ground. 3 #8 and 1 #10 will not go into 1/2".

Since the majority of his load will be a 240v heater he could down size the neutral to a #10, giving a total of 2 #8's and 2 #10's. Definitely not an ideal pull but it could work.

 

[James-W]

If it were me and I was running a new cable out to the garage, I would run a cable capable of handling 100 amps. My thinking is, if I am going to spend the time and the money to do this, I may as well do it so in the event that at some point in the future I want to add more equipment in the garage, I would have the available power to do it. We are only talking about a 25 ft run so the cost difference between the wire sizes shouldn't be all that terrible.

 

[mm08822]

Unfortunately, you will need a subpanel as this heater makes you exceed the one permitted circuit to a detached building.
i.e. - 3 conductors plus ground, subpanel with unbonded neutral block, ground block added, 2 ground rods. need main cb in subpanel if you ever plan to be over 6 throws of hand.

 

[E30bimmer]

Okay then, lots of opinions here. My buddy is coming over shortly to take a look at the situation and will post a follow up, but I'm kinda leaning toward running a new line(s) and 100A subpanel, even though heater only requires 30A. I like the option of being able to run cable internet out there. Using a network extender now and will sometimes drop the connection.

The thought trying to pull existing through the conduit and then getting stuck isn't ideal obviously.

This is the heater info btw:

http://www.northerntool.com/shop/tools/product_595_595

 

[zmaxmotorsports]

How about a picture of the wire that's in the conduit so we can settle that part of the question?

 

[E30bimmer]

How about a picture of the wire that's in the conduit so we can settle that part of the question?

It's just Romex. I decided that I'm going to wait til warmer weather and run a new 1" conduit and cable to provide for the heater, cable internet, air con, frig, compressor, etc.

Always go big as they say.

Thanks for the input guys.

 

[mm08822]

It's just Romex. I decided that I'm going to wait til warmer weather and run a new 1" conduit and cable to provide for the heater, cable internet, air con, frig, compressor, etc.

Always go big as they say.

Thanks for the input guys.

I hope this means that you plan to provide power for a new subpanel in the garage and not running several circuits out to the detached garage. If you care about being NEC complaint, you need the sub panel. Since you are planning to spend $ for improvements, it is better to spend it properly and be up to code so it doesn't haunt you later.

Also you should run the internet/low voltages/comms wirirng in a seperate conduit.

 

[73RR]

If you are trenching for a 1" tube then step up to at least 2" and then not have to worry later about how to get something else to the shop.
You already have the trench so the 2" pipe is only a small upcharge.

 

[E30bimmer]

I hope this means that you plan to provide power for a new subpanel in the garage and not running several circuits out to the detached garage. If you care about being NEC complaint, you need the sub panel. Since you are planning to spend $ for improvements, it is better to spend it properly and be up to code so it doesn't haunt you later.

Also you should run the internet/low voltages/comms wirirng in a seperate conduit.

Yes.

 

[James-W]

Sorry, I screwed up and double posted.

 

[James-W]

Okay then, lots of opinions here. My buddy is coming over shortly to take a look at the situation and will post a follow up, but I'm kinda leaning toward running a new line(s) and 100A subpanel, even though heater only requires 30A. I like the option of being able to run cable internet out there. Using a network extender now and will sometimes drop the connection.

The thought trying to pull existing through the conduit and then getting stuck isn't ideal obviously.

This is the heater info btw:

http://www.northerntool.com/shop/tools/product_595_595

I would say that is a very wise thing to do. It meets your current needs and it gives you plenty of power for future equipment should you need it.

 

[royalton10]

Don't do the 1" conduit. Go bigger. You could do a conduit for the sub panel, conduit for internet, and a spare. Overkill, yes! But you already have the trench opened. Use that to your advantage. Only 3 sticks of conduit for the trench.


Sent from my iPhone using Tapatalk

 

[zmaxmotorsports]

If you are trenching for a 1" tube then step up to at least 2" and then not have to worry later about how to get something else to the shop.
You already have the trench so the 2" pipe is only a small upcharge.

Definately.

 

[racingtadpole]

It's a code violation to pull the wire as you assemble the conduit. The conduit has to be assembled first, then the cable pulled.

Interesting, here, the cable is more often than not pushed through as the conduit is assembled.

I'm assuming the code violation is because the cable ends up glued to the conduit?

 

[CNGsaves]

+1 for . . . . . . Do It ONCE, Do It Right !!

Dig out portion next to house and garage to see what EXACTLY you have now. More than likely that 1/2" conduit it only useful for future low-voltage wires like CATV, Internet, Security, Phone, etc. Even at 1/2" it will be pretty skimpy. Eventually you'll need to remove that power, as garage can only have ONE source of power.

RE-TRENCH the 25' and put in 2" buried conduit for subpanel you'll add in garage. The "GJ economy" setup could include MHF (mobile home feeeder) aluminum 2-2-2-4 that will get you 90A at the garage at only $1.50/ft. Put in 100A subpanel with plenty of spaces for garage, and 90A breaker in house to feed the garage through MHF wire. Extra thing you need to do is also run the MHF wire in conduit all the way inside garage to the subpanel, along with conduit in house to main panel.

Sparky's will give you Copper option wire size as well.

 

[rburke65]

Do your self a favor and run the 2" PVC .....you will thank all of us here later.