# direct bury wire from house to garage??? help



## vinylman70 (Jan 19, 2010)

i have a double wide and a 30x40 garage my electricity to my house is under ground. on my box i have room to tie in to it. i will have to run wire to the garage 160 feet i am going to use direct bury wire but what kind? where do i buy it? lowes? all the wiring in the garage is done all i need to do is get the wire in the ground and hooked up at the house and garage. i will be useing a welder that needs 240v the most i will use at 1 time will be welder,lights and radio i plan on doing this in the next week or 2 so all the help would be nice thanks.also i have never done this so before i go trying to hook it up at the house do i just turn the main braker off that is out side? also will there be enough power to run the house and garage all at the same time because right now i have extension cords run out there right now and when i use a grinder it dims the lights in the house i am assuming it is because of the extension cords. thanks for your time and help.


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## kbsparky (Sep 11, 2008)

When I hear the term "double-wide" I think "mobile home".

If this is the case, then there should be an outside disconnect box with additional spaces for circuits to supply outbuildings, etc. This is where your feeder circuit for the garage should originate.

As for wire size, operating most welders would mean you need at least a 60 Amp feeder. I'd be willing to bet that many here would recommend a 100 Amp panel and feeder for the garage.

In any case, you can purchase a 4-wire underground feeder cable assembly called "URD" which would provide you with a 90 Amp capacity, if you bought the #2-2-4-6 Aluminum size. As for cost comparison, the #2 URD is probably less expensive than a #6/3-g type UF copper cable.

And, yes, it should be available at your local orange or blue home-horror store. :whistling2:


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## Scuba_Dave (Jan 16, 2009)

What is the service feed to the house ? 100a ? 200a?
Min I would do is a 60a feed, 100a is a good idea if you have a 200a service


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## vinylman70 (Jan 19, 2010)

yes it is a mobile home and the box on the house where we would tie in to is 200a and the box in the garage is 200a i have been told we want at least 100a to go to the garage and been told to go buy 3 peices of number 1 wire???? that will be rated to at least 100a does this sound right?? also the welder i will be running is 185a 230v..also i cant remember if i was told if this wire was aluminum or just wire and is this stuff direct bury or would it have to be in conduit if you all would like i can take a picture of both the outside box at the house and one of the box in the garage if you all think that would help us out so we are not guessing. thanks for the help


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## Scuba_Dave (Jan 16, 2009)

Detached garage you would need 4 wires:
2 hots, neutral & ground - ground wire can be smaller
Ground rods also required at the garage
#3 wire will give you 100a 7.6v drop over that distance (3.2%)
#2 wire will give you 100a 6v drop over that distance (2.5%)

So #2 copper would meet your needs
I'd use 2" PVC for ease of pulling, 1.5" would meet code


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## vinylman70 (Jan 19, 2010)

thanks scuba_dave so i need to buy 3 wires of number2 and 1 more wire for a ground what size would you recommend for the ground? and pvc pipe to put it all in. i should be able to do this all my self right without having to have the electric company connect it? reason i ask is because i have heard if the wire is to big then the electric company would have to do something with bus fuses or something. i dont plan on getting them or codes involved where i live is basically red neck country and people seem to go around them i know the garage is wired good because my dad did it and he now lives states away so im on my own now.only thing left to do in the garage is the plugs need screwed in but there are 2 copper wires just hanging in there do i just twist them together and be done.thanks


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## Scuba_Dave (Jan 16, 2009)

My understanding for ground is 2nd size smaller....so using #2, skip #3 & use #4 as the ground
Do you have fuses or breaker panel in the garage ?
Do you have a pci of what is in the garage ?
You do need ground rods if they were not run before

Here we are allowed to run sub-panels
But for "hot" connections to the meter the POCO & an electrician is needed
So if you have a breaker ahead of where you connect these & can shut the power off you are OK
You do not want to try connecting anything like this live


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## vinylman70 (Jan 19, 2010)

ok called the lowe's told them i needed a #2 wire to run from a house to a garage they said they had a 4 in 1 wire made with #2 copper wire. direct bury no need for pvc pipe. they said it was $1.82 a foot so i guess it will cost right at $300 does this sound like a good deal. then i guess i will still need a 100amp breaker to put in my conecting box on the house. so have i got this figured out or am i still missing anything?also will 12-18 inches underground be far enough i will be running it where nothing will ever run over it other than a lawn mower.thanks for all you help everyone..


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## tpolk (Nov 7, 2009)

pull a small rope thru pipes as you connect them to your garage for pulling wire later


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## Scuba_Dave (Jan 16, 2009)

I never run direct burial except on smaller 20a runs
I always run PVC, much easier to replace a wire
And it protects it from damage & digging animals

You'll need to go down 24" to the top of the wire is what I see in NEC table 300.5
Wait........Possibly 18" - I see that for 1 family & only for residential use
As long as it doesn't go under a driveway


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## vinylman70 (Jan 19, 2010)

the box in the garage is a breaker panel it has a lot of small breakers for the plug ins and stuff like that and has some big ones to wire the welder and air compressor i think they are a 30 and 50 amp breaker. here is a pic of the box on the house it is hard to see but the breaker on top is a 200 which i think is the main to turn on and off the power and below that where i pushed in the blanks is where i guess i would put in a 100 amp breaker to wire the garage correct???


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## vsheetz (Sep 28, 2008)

I recently installed a sub panel in my 24x30 workshop/garage. Running 240v welder, grinder, drill press, lights, large 240v table saw, chop saw, etc. 120' wire run in conduit. 100a sub panel fed by a 60a breaker in the main panel.

I think you will find it cheaper, easier, and better to go wires in conduit rather than direct burial cable.

Here direct burial has to be 24" down, conduit only 18" - that makes a BIG difference when digging the trench, especially a long one... the bottom is the hardest to dig, and the deeper the bottom the more difficult. Conduit is better as you can add or change easily in the future. Conduit is cheap - use a size or two larger than minimum needed for future additions/change and to make it easy to pull the wires.


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## codeone (Dec 31, 2009)

vsheetz said:


> Here direct burial has to be 24" down, conduit only 18" - that makes a BIG difference when digging the trench, especially a long one... the bottom is the hardest to dig, and the deeper the bottom the more difficult. Conduit is better as you can add or change easily in the future. Conduit is cheap - use a size or two larger than minimum needed for future additions/change and to make it easy to pull the wires.


Remember these measurements per the NEC are to the top of the pipe or wire.


1.​​​​Cover is defined as the shortest distance in millimeters (inches) measured between a point on the top surface of any direct-buried conductor,​
cable, conduit, or other raceway and the top surface of finished grade, concrete, or similar cover
:yes:


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## Nicksin (Jan 20, 2010)

The wiring sizing is about right. But... Save yourself some money and get a #4 or #6 ground. There is no need for a full size ground to be run in the pipe. You will have to put a seperate ground bar in each panel for this. a Sub panel which is what you have in your Garage is required to have a seperate ground bar. As for the ground rods once again there is no need to run any bigger than a #6 to them. This will meet code although i am not quite sure ground rods are required. I will have to look in my code book and get back to you. :thumbsup:


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## Nicksin (Jan 20, 2010)

Also be very careful getting advice from lowes or home depot. I have fun going in there and telling them what i am doing and see what they tell me i need. Its actually quite amusing


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## codeone (Dec 31, 2009)

Yes ground rods ar required at a sub panel at a seperate building. And if you are under the 2008 NEC you also need an intersystem bonding bar/lug.


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## vinylman70 (Jan 19, 2010)

Thanks for all the advise but i am getting lost when you all say save money and buy a smaller ground wire. And yes i know what you mean about lowe's when they say you need something when you know you dont. But if they have a 4 in 1 wire with 2 hot wire's and 1 neutral wire and 1 ground wire all number 2 copper wire all in one for 292 bucks how does a man save money buying 4 seperate wires 3 number 2 and say 1 number 4 for a ground when the price per foot is .80 you x's that by 4 thats about $515 my father in law has a bunch of pvc pipe out back by the woods he said i can have so i guess if i use the direct bury i will also put it in that will that work. I dont plan on ever running more wire to the garage as this will be all i need as long as it runs a welder and lights at the same time i am happy i dont plan on running a welder,lights,grinder,and a huge air compressor all at the same time so this should work right? Thanks everone you all are a big help i cant tell you how much you all have helped me.thanks let me know


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## Scuba_Dave (Jan 16, 2009)

Many people have "saved" money by burying wire
Many people never have a problem
Many have also cursed it when they have to dig it up & buy & bury new wire due to some problem with the direct burial wire

Once you bury conduit you can easily replace the wire if there is ever a problem
You need to use electrical conduit - grey....not white


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## vinylman70 (Jan 19, 2010)

ok. i have also been in the search bar and what i have also read and like what you have said is for people to use 3 number 2 wires and a green number 10 wire for a ground. with 2 8'x1/2'' ground steaks at the garage right. if i do that what size pipe do i need to use. 1 1/2 all 4 wires go in the pipe right? also just wondering why do i read that people have trouble with the direct bury just wondering what kind of problems are with it. also if i do stick with the direct bury can i run it in the pipe so it can be replaced if ever needed?? reason im full of questions is because im on a budget and i have had my garage since march of 06 and really want some electricity out there while i do have some money.i had the trench dug in 07 and filled it in this year and now have some money so i already have to do this work again.


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## Scuba_Dave (Jan 16, 2009)

You would use (3) #2 wires & I think #4 ground - 2nd size down
2 ground rods with #6 wire Min running to them
I'd run 2" pipe....1.5" would meet code

You could run the direct burial in the conduit
But you would need much bigger conduit due to the fact it is a cable

Problems with direct burial:
Critter chews on underground
Lightning strikes
Rock pokes thru the cable
not sure what else...and again it may never happen

I ran (2) 20a buried circuits out front & still used conduit


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## vinylman70 (Jan 19, 2010)

ok dave all makes since tomorrow i will check on the price of 3 #2 wires and a #4 wire all 160feet and i guess price on 160 feet of the pipe and see what it will cost that way then add the price of pipe to the direct bury and see what it will cost that way to. with the direct bury in the pipe should add security to it though right and be just about the same?? do you know about what the pipe runs? on just wire i will need 2 black for hot 1 white for neutral and what color for ground? or am i wrong? or is it all the same


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## kbsparky (Sep 11, 2008)

WE'd use (2) #3 hots, (1) #4 neutral, and (1) #8 ground. All installed in a 1¼" conduit. Fully rated for 100 Amps. #2 wires are overkill.


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## vinylman70 (Jan 19, 2010)

can some one tell me a web site that shows this wire because when i google it all it wants to show is either electric fence wire and wire for amp's aint having no luck lowes web site dont even show it but i did find the conduit it was je eagle 2''x10' for $2.98


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## vsheetz (Sep 28, 2008)

vinylman70 said:


> Thanks for all the advise but i am getting lost when you all say save money and buy a smaller ground wire. And yes i know what you mean about lowe's when they say you need something when you know you dont. But if they have a 4 in 1 wire with 2 hot wire's and 1 neutral wire and 1 ground wire all number 2 copper wire all in one for 292 bucks how does a man save money buying 4 seperate wires 3 number 2 and say 1 number 4 for a ground when the price per foot is .80 you x's that by 4 thats about $515 _*my father in law has a bunch of pvc pipe out back by the woods he said i can have so i guess if i use the direct bury i will also put it in that will that work.*_ I dont plan on ever running more wire to the garage as this will be all i need as long as it runs a welder and lights at the same time i am happy i dont plan on running a welder,lights,grinder,and a huge air compressor all at the same time so this should work right? Thanks everone you all are a big help i cant tell you how much you all have helped me.thanks let me know


PVC pipe for water usage, and electric conduit are differing. Per code, proper electic conduit is required.


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## vinylman70 (Jan 19, 2010)

just so you all know there are no codes involved here it will never be checked. where i live at it is basically do what you want to do. it's more less a red neck town. you go a county away it's like beeing in a city and you must follow code there is a big diff. between my county and the rest of tennessee. if anything were to ever go wrong it would just throw the breaker at the house i mean im confussed i have never done this my dad is a electrician he wired the garage and was suposse to do this to but he more less bailed and moved away so now it is up to me he said i need number 1 wire that will draw at least 150 amp then i have been told number 2 wire and in a more recent post it has been said use 2 #3 and a #4 and #8 and dad also said the direct bury from lowes would work as long as i dont try running everything at once at the most welder and lights. all i know is we are allowed to do this 1 time where i live to join on to the extension box off the house and run electric to a garage or what ever it be but we cant do it time and time again. or do it as a living unless you are licensed to. anyways thanks for all the help i just need to know the right wire to use so i dont waist my money. im not saying i wont buy the #2 wire but if i can save money and buy a cheaper wire that will work please let me know. if the guy that said #3,4,8 will work what does everone else think. thanks right now im pretty well thinking #2 and #4 or direct bury in conduit this is a great board and i appreciate every ones help greatly please dont take this reply wrong im just saying what i have been told and what little i know i already have $600 invested is just the wiring in the garage yes it was to dad 3 years ago but i still love the man even though i got the raw end of this


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## kbsparky (Sep 11, 2008)

The wire we use for this is type THHN-THWN-2. Most places call it THHN, although it is dual rated. This is copper conductors, and it is required to install it in conduit.

The direct-bury stuff would be commonly called #2 URD. This is an assembly of 4 aluminum conductors twisted together, with the neutral and/or grounding conductors reduced in size. I've seen it configured as either 2-2-2-4, or 2-2-4-6. 

While a 3-conductor version of #2 URD may be available, you need 4 conductors for this project.

Places like Lowe's and the Home Depot sell it as 100 Amp mobile home feeder. 

You can use a 100 Amp breaker, and directly plug it into the blank spaces in your main disconnect box.

If you use the direct-bury URD cable, you still will need a short section of PVC conduit to sleeve the wire where it emerges from the ground, for physical protection.

Does that help?


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## vinylman70 (Jan 19, 2010)

thanks kbsparky i understand thanks for all the help.


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## vinylman70 (Jan 19, 2010)

ok i went and seen our main man of our town that calls all the shots he also owns his own hardware store and has been building some nice 150,000+ new homes down the main highway. he said we needed to do direct bury and he has never had any problems with it for 17+ years he said we would use #3 aluminum wire. he said there was no since in having a 4th wire for ground at all and said it would pull every bit of 100 amps all this at $1.20 a foot so it looks like this will be less expensive than i thought. and said they would also do it for me for $200 thats digging a new trench and hooking it all up:yes: he also asked if i wanted codes to inspect i said na he said thats fine........................


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## Scuba_Dave (Jan 16, 2009)

A 4th wire is required for safety & to meet current code
#3 Alum is good for 75a max


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## vinylman70 (Jan 19, 2010)

i see what your saying scuba dave i guess there must be big diff. between our regions. anyways the welder shows it has the amp range of 25-185 and is 230 volt so do you think the 75 volts that you say i will only get run that welder and lights at the same time remember i will not be running welder,lights,and a 230v air compressor and small tools at one time at the most just welder and lights when i asked him about the #2 direct bury wire he said no one ever uses it because it is expensive and that every body just about uses this direct bury aluminum wire and it is very popular and said it would pull 100 amp unless we hit the 200 foot mark and it would be all i need. he said just about every one was useing this same wire around here??????????let me know.


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## Scuba_Dave (Jan 16, 2009)

There is no difference
The fact that some people choose to ignore the *National* *Electric Code* (NEC) & risk a fire, or possible eletrocution should be a crime

With voltage drop you are down to about 50a at full voltage
If you never pull over 50a 240v you won't have a problem
If you have a motor or something else that does not like voltage drop you will probably have a problem


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