Largest Wire Through 3/4" Conduit?

[AndrewDouglasBird]

I'm renting a room in a house along with a detached garage. The garage is currently powered by a single 14/2 wire, which is not adequate for my needs. I have a 110v mig welder and with light/radio/whatever else might be on, welding will be a challenge.

The garage is wired via conduit from a 15 amp breaker in the panel in the house. The house was remodeled within the last 5 years, so all the wiring and panel are new.

What's the biggest wire I could pull through a piece of 3/4" PVC conduit?

I'd like to re-run this and put in a 30 amp breaker if possible with a small sub panel in the garage with 2 breakers. One 15A for lights, one 20A for outlets. Is something like this even to code?

I was thinking a box like this:

http://www.amazon.com/dp/B00RZZ9CHA/?tag=atomicindus08-20

Thanks.

 

[JunkBonds]

You don't own the place. You cannot do this work.

 

[ltusler]

look up conduit fill ratio

 

[maxwage]

You don't own the place. You cannot do this work.

Damn you're quick to shut him down, but given the limited info on the OP situation, this isn't necessarily the case.

I've lived in several rentals. Because of the nature of my employment at the time, owning wasn't feasible. I always rented a place with some type of shop space or garage. About half of them weren't adequate for a workable shop space, power-wise.

If you have a rapport with the landlord, ask them. I did this and offered to cover the expenses. In a few cases, they split the cost. It adds value to the property and makes for a happy tenant. A happy tenant generally pays on time and treats the place as their own.

It's not like your wanting to put 3 phase in to run an industrial lathe or machinery!

Ask for permission, and if granted, proceed from there.

People will say, "why waste your $, you don't own?" Well sure, if you only plan on staying there for a couple months. But I saw it as, it makes me happy, I get to do what I love, and potentially help someone else down the road use the space like I did.

 

[JunkBonds]

There is no way I would let any of my tenants do any work on any of my places. Especially electrical.

They screw it up and who's azz is on the line?

Try explaining that one to your insurance company after the tenant electrocutes himself or worse...someone else. Sir, he did ask if he could do the electrical work himself and I said yes. I had no idea he was a clueless, talentless person doing non-inspected work.

 

[Pwrgeek]

Almost all of the DIY contractor license exceptions are for the owner only. You'd almost certainly be outside the law doing this as a tenant. That being said you can get 4 x #6 in a 3/4 conduit which would get you a 50A 240V circuit. Probably more than you'd ever need in a hobby garage of this size.


Sent from my iPhone using Tapatalk

 

[rburke65]

It sure takes a while to get an answer to a simple question.

 

[AndyCBR]

I would suggest individual conductors.

You can pull 3 THHN #10 and one THHN #12 for ground in a 3/4 conduit.

Make a proper splice for the pulling head and use lubricant. Make sure a helper feeds the wire so there are no snags.

ETA: For a subpanel you will need a dedicated neutral and most places will require a dedicated ground rod at the detached structure.

Get help unless you have experience with this work.

 

[teamextreme]

You can pull 3 THHN #10 and one THHN #12 for ground in a 3/4 conduit.

Ya, you can also pull 3 #18, but he was asking for what the largest size you can pull which was answered by PwrGeek as 4 x #6, good for 50 amps. You can downsize one of those #6 for the ground to #10.

 

[Pwrgeek]

Ya, you can also pull 3 #18, but he was asking for what the largest size you can pull which was answered by PwrGeek as 4 x #6, good for 50 amps. You can downsize one of those #6 for the ground to #10.

You can downsize to #10 per code but I prefer full size (size of neutral) ground conductors for detached structures with four wire feeds. Since the neutral in the second structure is going to be isolated (because of a stupid code rule) that ground conductor is your only path for ground fault current back to the main panel.


Sent from my iPhone using Tapatalk

 

[alfredeneuman]

I would suggest individual conductors.

You can pull 3 THHN #10 and one THHN #12 for ground in a 3/4 conduit.

A 30 through 60 Amp circuit requires a #10 ground conductor.
#10s would require a #10 ground, not a #12.

 

[AndrewDouglasBird]

Man, people sure do get their ******* in a bunch on the internet.

The landlord is a contractor and was the one who remodeled the house. He's already ok'd me making changes (this isn't the first, see my garage door gap thread) and would also likely be helping.

There is one caveat. They use the same conduit from the house to also split off somewhere (haven't determined where yet) and run power to the chicken coop. So currently there are (2) 14/2 wires in at least part of the conduit.

Is there a way to only pull 3 wires (two for power/neutral, one for ground) since I don't need 220? I was thinking I could just install a 30amp breaker in the house panel, then use this to feed the two breakers in the garage, no 2nd hot needed. I was thinking a breaker like this:

 

[CJ7VFR]

So currently there are (2) 14/2 wires in at least part of the conduit.

Is there a way to only pull 3 wires (two for power/neutral, one for ground) since I don't need 220? I was thinking I could just install a 30amp breaker in the house panel, then use this to feed the two breakers in the garage, no 2nd hot needed...

By saying there is two 14/2 two wires already in the conduit, do you mean two lines of romex, or something similar, like maybe UF-B?

I do believe that NEC code prohibits the use of "Romex" inside conduit that goes underground and outside. The Sparkies on this forum will have to chime in on that.

But with what you are saying, two lines of 14/2 in the conduit already means that at a minimum, there are six 14 gage wires in there, and that may already be pushing the capacity of what can safely be put into 3/4 inch conduit.

The circuit type you might want to look at running into the garage is a MWBC (multi-wire branch circuit) from the main panel.

This would allow you to run two hot wires with one neutral and ground into the garage off of a 20 amp double pole breaker in the main panel. This would give you one feed for your lights and one for your outlets.

Search this site for it. There is tons of info on how to do it.

Jim

 

[AndrewDouglasBird]

Yes, two pieces of romex. I'm not familiar with the different types, but it isn't standard, it's grey, maybe meant for direct burial or in conduit or something?

 

[wyliesdiesels]

I would suggest individual conductors.

You can pull 3 THHN #10 and one THHN #12 for ground in a 3/4 conduit.

Make a proper splice for the pulling head and use lubricant. Make sure a helper feeds the wire so there are no snags.

ETA: For a subpanel you will need a dedicated neutral and most places will require a dedicated ground rod at the detached structure.

Get help unless you have experience with this work.

U cannot downsize the EGC for circuits fed by #14, #12, and #10...

Man, people sure do get their ******* in a bunch on the internet.

The landlord is a contractor and was the one who remodeled the house. He's already ok'd me making changes (this isn't the first, see my garage door gap thread) and would also likely be helping.

There is one caveat. They use the same conduit from the house to also split off somewhere (haven't determined where yet) and run power to the chicken coop. So currently there are (2) 14/2 wires in at least part of the conduit.

Is there a way to only pull 3 wires (two for power/neutral, one for ground) since I don't need 220? I was thinking I could just install a 30amp breaker in the house panel, then use this to feed the two breakers in the garage, no 2nd hot needed. I was thinking a breaker like this:

Is this 14/2 NM-b aka Romex? If so thats not allowed underground or outside. NM-b is dry locations only.

Also, its gonna be a bear pulling wire through that conduit because of the existing wires.

 

[Zeke]

U cannot downsize the EGC for circuits fed by #14, #12, and #10...



Is this 14/2 NM-b aka Romex? If so thats not allowed underground or outside. NM-b is dry locations only.

Also, its gonna be a bare [sic] pulling wire through that conduit because of the existing wires.

Nigh impossible.

 

[wyliesdiesels]

Damn (DUMB) smartphones

 

[zmaxmotorsports]

So how many bends are in the conduit between point a and point b? That would make a big differance in what I would want to try and pull though it any way,Do a little bit of investigating first .

 

[Fallon]

http://www.electrician2.com/calculators/rf_calculator.html will answer your fill questions. However you probably want to listen to everybody else about their ideas on what type of wire is permitted in conduit & the fact it's almost impossible to pull additional wire through (really, you need to pull that wire out, then pull it back with the new wire at the same time).

 

[zmaxmotorsports]

Almost all of the DIY contractor license exceptions are for the owner only. You'd almost certainly be outside the law doing this as a tenant. That being said you can get 4 x #6 in a 3/4 conduit which would get you a 50A 240V circuit. Probably more than you'd ever need in a hobby garage of this size.


Sent from my iPhone using Tapatalk

The fact its a rental property normally throws the home owner being able to pull his own electrical permit out the window around here anyway.

 

[wyliesdiesels]

The fact its a rental property normally throws the home owner being able to pull his own electrical permit out the window around here anyway.

Same here. Home must be owner occupied...

But supposedly the owner is a contractor so this is a moot point.

 

[zmaxmotorsports]

Same here. Home must be owner occupied...

But supposedly the owner is a contractor so this is a moot point.

Well if hes a general that doesnt mean he can pull electrical/plumbing or hvac permits though.

 

[AndrewDouglasBird]

There are at least (3) 90° fittings, so it's looking like this just isn't feasible. Pulling the other wire out first is a big undertaking as it is at least twice as long as the run to the garage.

Somewhere, likely buried, is a Y or T connector as well because two wires go in and each comes out at a different location.

 

[mike93lx]

Can you just use a 10 gauge extension cord from the house when you need the welder?

 

[AndrewDouglasBird]

Can you just use a 10 gauge extension cord from the house when you need the welder?

This is probably what I will do. There is an exterior outlet on it's own circuit 30 ft in front of the garage.

 

[JPinSTL]

Look at this problem another way. Do you have an electric dryer with a 4 prong plug? Is that dryer outlet reasonably close to the garage? Buy some #8 or #6 SO Cord and make an extension cord with a small breaker box attached. Wire in a few GFI Outlets in Boxes on the side. Square D makes a 6 space 100A panel for around $35. Or look at the temporary power distribution panels with outlets included for $100+. You can take this with you after you leave that rental and you'll then have a nice extension cord for that larger welder you will buy eventually.

Or look around Craigslist for a spider box which is essentially what you would be building, but new they are crazy expensive.

 

[AndrewDouglasBird]

The washer/dryer are in the basement probably 100ft. form the garage, so that is a no go.

 

[Charles (in GA)]

Along with all of the conduit issues, you would have to install a ground rod (two actually) as the single circuit to the detached is allowed under rules that dont require a ground. As soon as you install a subpanel or multiple receptacles, things have changed.

Charles

 

[bubinga]

Right, my landlord said I could wire what ever I wanted to(on my dime.....)

Sent from my MotoG3 using Tapatalk

 

[CNGsaves]

. . . . . IF . . . you plan on staying there a long time . . . .
. . . .
. . . . . . . then, Do It Once, Do It RIGHT !!!

As GJ Sparkies have said, use the individual wires to get most you can to a subpanel out in detached garage. You can only have ONE power source to detached garage and yes you'll need 4 wires, along with ground rods outside garage near the subpanel.

I'd try for 40 or 50 amps if you can pull large enough individual wires for that and put in subpanel (if over 6 breakers then it needs main shutoff on subpanel). A 20 space panel is what I'd recommend so just get 100A of same brand as what you have in house. The house breaker feeding the garage will need sized appropriately for wire you have running to detached garage. Good luck.

P.S. Forgot the chicken coop - - - - run new buried conduit instead from the detached garage over to chicken coop with proper underground wire. Abandon the old buried conduit after you remove the incorrect wire. So chicken coop will be it's own circuit off the detached garage subpanel.