Having trouble finding clear answers to what I think are basic questions.

[NoPressure]

I'm trying to do as much of my electrical work in my new shop as possible. I have a few questions that I can't find clear answers to.

1. How close to the power pole should my trench be dug and also how deep should it be? I'll be running 2" gray PVC.

2. What type of wire should I use for 220v welder, compressor, car lift outlets?

3. I've seen where some people use 14-2 and 12-2 for lights and regular 110v outlets and that others just use 12-2 for everything. Is there a big price difference in the two? If it's reasonable to run 12-2 for everything I'd rather do that just for the convenience of buying/using one type.

I've been trying to do my own research the last few days but can't find a source that has good general info in one place.

 

[kd3pc]

1. The folks who make the rules will tell you what they require. Power company is usually the best and easiest place to start.

2. Depends on current requirements (amps) and whether any of the loads are electric motors. Location of and requirements for disconnects can impact the choice of wire.

3. I use 12 for both lights and receptacles, again wire size is related to current requirements..

best of luck

 

[timgr]

12-2 will be more expensive than 14-2 for 15A circuits. $56 vs 36$ for 250' at the Home Despot. Also 14-2 is easier to work with IMO. Otherwise, no reason not to use 12-2 for outlets and lights. May as well make all your outlets 20A, if you run the needed wire.

I used 10-2 for my compressor and heaters, at 30A. Pretty sure you need to go to 8-2 for a 50A circuit. Check your welder specs for the required amperage. Most 220 welder cords need a 6-50R receptacle, which is rated 50 amps.

 

[Zeke]

I'm trying to do as much of my electrical work in my new shop as possible. I have a few questions that I can't find clear answers to.

1. How close to the power pole should my trench be dug and also how deep should it be? I'll be running 2" gray PVC.

2. What type of wire should I use for 220v welder, compressor, car lift outlets?

3. I've seen where some people use 14-2 and 12-2 for lights and regular 110v outlets and that others just use 12-2 for everything. Is there a big price difference in the two? If it's reasonable to run 12-2 for everything I'd rather do that just for the convenience of buying/using one type.

I've been trying to do my own research the last few days but can't find a source that has good general info in one place.

Have you considered reading?

You can buy an out-of-date version for as low as $0.20 on Amazon. There are some significant changes in the last decade but the basics remain the same.

 

[NoPressure]

Thanks guys

 

[NoPressure]

Have you considered reading?

You can buy an out-of-date version for as low as $0.20 on Amazon. There are some significant changes in the last decade but the basics remain the same.

I'll look into that. Thanks.

 

[Norcal]

12-2 will be more expensive than 14-2 for 15A circuits. $56 vs 36$ for 250' at the Home Despot. Also 14-2 is easier to work with IMO. Otherwise, no reason not to use 12-2 for outlets and lights. May as well make all your outlets 20A, if you run the needed wire.

I used 10-2 for my compressor and heaters, at 30A. Pretty sure you need to go to 8-2 for a 50A circuit. Check your welder specs for the required amperage. Most 220 welder cords need a 6-50R receptacle, which is rated 50 amps.

8/2 NM is 40A max.

 

[sberry]

The code is a poor diy manual. The main reason to use 14 is that it is a bit easier and great for all those fussy fixture wires, great for switch loops where they have little load. I use it for lights and separate a couple circuits for tools. The 15A recepts are fine on 20A circuits and a welder circuit can be tailored for the machine but the only one requires a wire larger than a 10 cable is 250A migs if they come with factory cord and plug.

 

[sberry]

Actually 8 is good for 100,,, just depends on how long you are going to run it.

 

[txvwnut]

I can answer question #1, right up to the pole. At least that's what I was told when I buried my service run.

For question #3 I ran 12/2 for all the 110v stuff as it's what my electrician buddy handed me. #10 for the 220v compressor and #8 for the welder. But the welder run is only 12" long.

 

[kd3pc]

I can answer question #1, right up to the pole. At least that's what I was told when I buried my service run.

In our area, the power company wants you at least a foot off the pole, so as to not upset it or loosen it.....too many backhoe "operators" can't tell when the bucket touches concrete or posts.

They then come out and scrape away what is left and give you a bit to lay in your PVC, if you are nice, they wait and finish. If you get too noisy, they will say see you in a day or two.

If they know the contractor who trenches, then you can go right up and lay the sweep where it should go. Inspection OK - then cover it and wait for the line crew.

 

[GarageGuy89]

I'm no electrician but this is how I understand it.

2)This varies per number 3 below

3)Wire size is determined by maximum amps on the circuit, ie the circuit breaker at the panel. Every gauge wire is rated for a maximum amperage, if you exceed that amperage the wire fails, ie burns up or other problems, thus the reason for the breaker. The breaker will flip before the wire burns up.

You can't put smaller wire on a higher rated circuit for this reason, but you can put bigger wire on a smaller circuit.

The bigger wire on a smaller circuit comes into play with voltage drop. So, the longer the run the more voltage drop. The smaller the wire the more voltage drop. You mitigate voltage drop by increasing wire size.

 

[ard]

I am going to also opine that 'reading the code' is not going to be helpful. I recall when I was first learning, I had little tags of paper (before stickies) that Id tape in place to help track the stuff in the code book... it is convoluted to say the least.

There are some decent books, I remember getting the first edition of Wiring Simplified.. (currently in 44th edition...yikes huh? This focuses on JUST residential- not movie theaters, slaughterhouses and nuclear power plants.

Personally I just run #12. It isnt enough money to be worried about it for a one-off job. Plus, in the future you need to drop a receptacle somewhere, or whatever, you have #12 and 20A circuits everywhere.

 

[bczygan]

And you can read the current NEC for free online.

And:
https://www.google.com/search?q=basic+electrical&ie=utf-8&oe=utf-8#q=basic+electrical+wiring

 

[zmaxmotorsports]

As far as depth is concerned 18" is normally considered the minimum,but I tend to go more like 24-30" to allow for grading work.
It doesn't take much for a guy finish grading a yard with a skid loader to take 18" down to less than 10" if he's not watching what he's doing.
As far as the 12g versus 14g goes I generally see no reason to use 12g wiring for lighting circuits in a garage,it's not the price so much as the fact that 12/2 is so much stinking harder to work with than 14/2 (especially overhead)
For your outlets I'd run everything in a shop with 12/2,furnace circuit can be 14/2.

 

[alien]

NEC Handbook is a good resource

HANDBOOK

 

[txvwnut]

In our area, the power company wants you at least a foot off the pole, so as to not upset it or loosen it.....too many backhoe "operators" can't tell when the bucket touches concrete or posts.

They then come out and scrape away what is left and give you a bit to lay in your PVC, if you are nice, they wait and finish. If you get too noisy, they will say see you in a day or two.

If they know the contractor who trenches, then you can go right up and lay the sweep where it should go. Inspection OK - then cover it and wait for the line crew.

Trencher to within a couple feet then hand dug the rest of the way then I had to run pipe up about six feet, as per the poco.

 

[NoPressure]

Thanks for all the replys. Very helpful information here. As for the trench I will call the utility company next week and ask them directly about how close to the pole to go. I assumed they would want me to stand off at least a foot or two to avoid disturbing the pole.

As for the wiring I think I'll run the lights with 14. I will have about 20' of scissor trusses so it sounds like 14 will be easier to work with in those spaces. I'll do all the 110 outlets with 12.

Still not sure about welder and compressor. The shop will be 34' wide x 26' deep. The breaker box will be in the front left corner. The compressor will be outside the back right corner. So about 60' from the breaker box not counting for the bends the wire will make to get there. I want to have four 220v welder plugs on the same circuit. Only one would ever be used at a time. I just want to be able to get any where in the shop. 1 plug in the center of each side wall (26' walls) and two plugs evenly spaced in the back 34' wall. So the furthest plug from the breaker would basically be on the opposite side of the shop from where the breaker box will be. I hope that makes sense. I would have drawn something out but I'm posting from my phone.

 

[timgr]

Wire gets expensive as the conductor diameter goes up. 10-2 you can buy at the Home Depot in a coil, and the price is reasonable - that's probably what you need for your compressor. You may want to put one centrally placed welder receptacle and buy an extension cord. A 50' extension cord is more than $100, but I expect it will be considerably cheaper than running #8 or #6 wire around the perimeter of the building, plus the three receptacles and boxes (easily an additional $50).

 

[wyliesdiesels]

I'm trying to do as much of my electrical work in my new shop as possible. I have a few questions that I can't find clear answers to.

1. How close to the power pole should my trench be dug and also how deep should it be? I'll be running 2" gray PVC.

2. What type of wire should I use for 220v welder, compressor, car lift outlets?

3. I've seen where some people use 14-2 and 12-2 for lights and regular 110v outlets and that others just use 12-2 for everything. Is there a big price difference in the two? If it's reasonable to run 12-2 for everything I'd rather do that just for the convenience of buying/using one type.

I've been trying to do my own research the last few days but can't find a source that has good general info in one place.

1) depends on PoCo. Call them. U wont find this anywhere but either on the PoCo's site(if they have one and have that info there) or in their "blue book"

2) Wire for all of those is sized differently

wire for compressor circuit will be sized based on HP rating on motor and if the HP is over 3HP then it will need to be hardwired(no outlet) unless expensive pin and sleeve plug and outlet is used or similar that has a HP rating equal to or greater than the HP rating on the motor.

If compressor will be hardwired u will also need a disconnect if more than 50' away from and not within sight of the electrical panel.

Wiring for lift depends on motor and what manufacturer calls for.

12-2 will be more expensive than 14-2 for 15A circuits. $56 vs 36$ for 250' at the Home Despot. Also 14-2 is easier to work with IMO. Otherwise, no reason not to use 12-2 for outlets and lights. May as well make all your outlets 20A, if you run the needed wire.

I used 10-2 for my compressor and heaters, at 30A. Pretty sure you need to go to 8-2 for a 50A circuit. Check your welder specs for the required amperage. Most 220 welder cords need a 6-50R receptacle, which is rated 50 amps.

What is the HP rating on the compressor?

and 8/2 NM-b is limited to 40a.

I'm no electrician but this is how I understand it.

2)This varies per number 3 below

3)Wire size is determined by maximum amps on the circuit, ie the circuit breaker at the panel. Every gauge wire is rated for a maximum amperage, if you exceed that amperage the wire fails, ie burns up or other problems, thus the reason for the breaker. The breaker will flip before the wire burns up.

You can't put smaller wire on a higher rated circuit for this reason, but you can put bigger wire on a smaller circuit.

The bigger wire on a smaller circuit comes into play with voltage drop. So, the longer the run the more voltage drop. The smaller the wire the more voltage drop. You mitigate voltage drop by increasing wire size.

This is true for general use/purpose circuits but not for motor circuits which can have wire sized smaller than the breaker rating.

 

[sberry]

Find 1 good place for a welder outlet. If it doesn't work out move it. Do you really need to weld in every corner?

 

[NoPressure]

Find 1 good place for a welder outlet. If it doesn't work out move it. Do you really need to weld in every corner?

Short answer, yes. Long answer, right side of the shop will be where my welding table is set up. Middle of the shop is where cars will be parked for any in car fabrication work (roll bars, cages, tin work, etc.) Left side of the shop will be where the lift is and will see the least amount of welder action but in theory I would also need it over there from time to time.

I've considered one plug and a long extension cord but couldn't figure up the price difference between that and actual plugs since I didn't know what wire I would be using.

All this has been based on the assumption that it made the most sense to bring the power into the shop on the front left corner because this is the closest and straightest shot to the power pole, but the majority of my tools and equipment will be on the right side of the shop which is opposite of the breaker box. Would it be cheaper to run the power in to the front right corner because I would have much shorter runs of wiring to the outlets on that side? I'll have several more outlets on this side of the shop. The compressor will also be on this side. Basically the only thing on the left side of the shop as far as wiring will be a couple outlets, power to the lift, and lights.

I'm not sure if I would be able to make a straight shot from the right side to the pole. Depends on how deep the trench needs to be. I'm just thinking out loud at this point. I'll try to post a picture of the layout because I doubt I'm explaining this very clearly lol

 

[OccupantRJ]

Could you mount a welder receptacle on the lift post closest to the center of the shop?

 

[wyliesdiesels]

Yes it is usually cheaper to put the panel in a spot that will reduce the amount of wire used for branch circuits.

What model welder will u have?

Keep in mind some jurisdictions dont allow more than one outlet on a 240v circuit.

 

[NoPressure]

This is v1.0 in sketchup. This is a couple months old and no longer accurate, but the only difference is walls will only be 10' 5 1/2" and roll up doors will only be 8' high. In this picture the walls are 12' and doors are 10' tall. Anyway, the front left corner is the closest point to the power pole. Left garage door is where the lift will be, right garage door will be the open bay for in car fab work, and the remaining space on the right side is where the welding table, benches, tool boxes, tools, etc. will be.



Here's a rough idea of the layout inside

 

[NoPressure]

Yes it is usually cheaper to put the panel in a spot that will reduce the amount of wire used for branch circuits.

What model welder will u have?

Keep in mind some jurisdictions dont allow more than one outlet on a 240v circuit.

Ok so I will probably bring the power in on that front right corner. So would it be considerably cheaper to just have one welder outlet on the right wall and a long extension cord? Versus a plug on the right wall and one on the back wall?

At the moment I have a miller 251 mig and an AHP tig. The AHP can run on 110 but it's not ideal. I also have a miller 140 mig which is a 110 unit.

 

[bczygan]

I would want a welder outlet at the front doors so I could work outside.

 

[AntonLargiader]

Our welder has a 20'+ cord on it, and then the gun itself has a 10' or so cord on it, so we can go pretty far with just one outlet. If I (with that long cord on the welder) were in your shoes I'd start with an outlet in the lower right edge of the diagram and then see what else you really need.

 

[NoPressure]

Our welder has a 20'+ cord on it, and then the gun itself has a 10' or so cord on it, so we can go pretty far with just one outlet. If I (with that long cord on the welder) were in your shoes I'd start with an outlet in the lower right edge of the diagram and then see what else you really need.

I think that's what I'm going to do. I can always add an outlet somewhere else if it becomes a problem.

This thread has been extremely helpful. With all the help I've gotten here I think this plan will be far more simple and less overall wire than what I was thinking about to begin with.

 

[75gmck25]

Also consider areas where you might use 14/3 or 12/3 cable to reduce the number of cables you need to run. For example, with a 14/3 run you can use one NM cable run to switch two different sets of lights in the ceiling, or a light and a fan. With a single 12/3 cable you can also connect your wall receptacles into two different circuits, usually alternating the connections so that every other 20 amp receptacle is on a the opposite circuit.

Bruce

 

[tyme2par4]

I would want a welder outlet at the front doors so I could work outside.

That's what I was thinking. Put the outlet either between the 2 doors, or between the entry door and garage door. With a 20ft power cord, you would reach most of your shop from there.

 

[NoPressure]

That's what I was thinking. Put the outlet either between the 2 doors, or between the entry door and garage door. With a 20ft power cord, you would reach most of your shop from there.

I thought about that but probably 75-80% of my welding will be done on the right side, on the table, so I'd like to have the plug over there that way I don't have to use the extension cord the majority of the time.

I made sure the shop and doors were big enough that I could get anything I own inside to work on. I'm not saying the need to weld outside will never come along but I've never needed to in my current attached garage that is only 24x24ish with 9x7 doors. Worst case scenario I could borrow a generator and use my 110v mig or run the tig on 110v.

 

[NoPressure]

Also consider areas where you might use 14/3 or 12/3 cable to reduce the number of cables you need to run. For example, with a 14/3 run you can use one NM cable run to switch two different sets of lights in the ceiling, or a light and a fan. With a single 12/3 cable you can also connect your wall receptacles into two different circuits, usually alternating the connections so that every other 20 amp receptacle is on a the opposite circuit.

Bruce

Good advice. Thank you

 

[GarageGuy89]

No Pressure:

My garage is the same setup as that, dimensions almost the same as well. Two garage bays with a shop area on the side. Mine has the shop area on the left though, and there is a wall that separates the garage bays from the shop area. My breaker box is located in the upper right corner, but that is because it's only about a 20' stretch to the utility pole from there, and I wasn't the one who built it. I like to have the breaker where I can easily access it for adding circuit and what not, somewhere I don't have to move/remove drywall etc, all the time to add stuff.

I went throughout the same conundrum as you though, with wanting a bunch of welding outlets for versatility and placement of the welder. What I ended coming to the conclusion on is to place the outlet between the two garage bays (centrally located) and be done with it. After doing research there is too much confusion with having multiple 50 amp outlets on the same circuit and by the time your all said and done an extension cord will be able to reach all points of the shop and be cheaper. By having it between the two garage bays I can use the extension cord to stick weld outside on the pavement where I don't want sparks flying in my shop, and the tig welding could be done inside just about anywhere. A 25' or 50' (50) amp RV cord can be had for less then $100. That in itself is cheaper then the big #6 wire. Add the receptacles boxes, etc...and multi outlets becomes more expensive then one good placed outlet with an extension cord.

 

[bczygan]

Since your equipment will be on the right side, that's where the panel should go.

This also means that the welder outlet would be right close to it, so you could afford to run a separate circuit for another outlet between the OH doors. Still a bit more $, but very flexible. And you could do it later.

 

[handymancanfixit]

Actually 8 is good for 100,,, just depends on how long you are going to run it.

Just curious....where did you see that 8 awg wire is good for 100 amps?

 

[Crazyjake8493]

I use 14/2 for lighting-only circuits, but if you only wanted to buy one you could run 12/2 for everything. Last time I bought a 250' roll it was $30 for 14/2 and $41 for 12/2

 

[sberry]

Just curious....where did you see that 8 awg wire is good for 100 amps?

Its short circuit is 100, a 200 synch welder allows number 8 in pipe and 100A breaker. But to follow the letter here the 251 needs a 6 cable and a 50A breaker. It comes with a heavy cord. You wont use the power but the machine is capable given a different wire and gas than most garages of this nature use.
I use a 10 cord on mine on the rare occasion its away from its home port. I only run it half throttle and only 50%, never overheats the wire.

 

[ard]

Just curious....where did you see that 8 awg wire is good for 100 amps?

"good" as in "I had it to 100Amps for a bit and it didnt melt or brun"

not "good" as in "Per code you can run 100A in #8 in your walls"





NoPressure...like the dawgs in the layout!

 

[sberry]

No you can't run it in the wall. That is for single circuit in pipe hard wired to the machine.