[John Garrison]

There are two garages on my property and the closest one to the house my wife uses for her cars and I also use it as my workshop. We'll call this garage #1. Anyway on the back forty there is a garage that is closer to where I keep all my project rigs(wife likes them away from the house) and I'd like to start using this as a part-time workshop instead of a storage building for those days when I don't feel like dragging my works-in-progress all the way over to my leanto in the rain or snow to get worked on. This is garage #2. Anyway, this garage has power to it from the previous owners but it kind of has me scratching my head and wondering if it will be alright to use even as a part-time shop even though the previous owners were.
My electrician father and I upgraded my house from fuses to a 150amp breaker panel about 6 years ago but we did not hook up the wires that use to run out to garage #2 because he said he was going to fix it up the right way for me. He recently passed away and now that I'm kind of getting motivation back to work on projects I need power out in garage 2.
Garage #2 is setup up as follows: There is one 220V wire along with one 110V wire buried together in underground conduit going from house to garage. Those wires are currently hooked to nothing at the basement panel. When they enter the garage the 110V wire goes to an on/off switch which is daisy chained to 4 outlets, one of which has an overhead light plugged into it which seems fine unless I were to run a bunch of stuff at once. My concern is the 220(240, whatever) wiring setup. They just have the 220 wire come in from the ground and to a junction box in the garage and from there it feeds one outlet for a welder and that outlet goes to an outlet they had an air compressor hooked to. Does this seem acceptable to use part-time or should I install a separate breaker box in the garage that feeds each the compressor and the welder? Those are the only two things that are 240V I plan on running out there just as the previous owners did.
In the house where my father left those two wires from garage #2, should I just hook the 110 wire into it's own breaker and install a 60amp breaker in my breaker box for the 240V welder and compressor? Any advice is appreciated.

 

[KellyfromVA]

There are several factors to consider: What is the existing type and gauge of wire going between the house and Garage #2? Depending on the prior installation, someone could have buried Romex(tm) in the ground and connected it up to 220V. Romex is not direct-bury rated. If your garage panel is set up for 60A, then you should size the feeder line between a 60A breaker at the house panel with direct-burial or feeder in conduit rated at no less than 110% of the maximum load. When deciding what conductor size of feeder to use, make sure you include the distance between the garage and main panel. For the sake of discussion, lets assume you have a distance of 100' between the main house panel and the garage:

CM = (25*I*L)/V

CM = Circular Mils
I = Max Load Current
L = Length in Feet
V = Max voltage drop

Given that the max voltage drop should be 2% of supply or in this case 2.4 volts (120V on each 'hot' wire)
I = 60
L = 100
So the required CM = 26500
6 AWG is about 26251 (working backward would give V of 2.412)

In theory you should use AWG 4, in reality that circuit will never see 60A so AWG 6 is fine.

Remember, the higher the voltage, the lower the current draw. So an average air 30-60 gal compressor that is 220V single phase/single stage, would only draw about 20A. Depending on the size of your welder, you could draw between 20-30A. Lighting would be less than 15A and normal plug-in use would probably average about 20A, worst case. So a 60A breaker to a sub panel in the garage would be a good choice for average non-commercial use. Just remember to run both 220V, plus neutral and a separate ground wire between the main and garage sub panel.

 

[John Garrison]

The 120V wire looks to be modern plastic sheathed and so is the 240V. The wires are not directly buried, they are in conduit. The 120 is standard 14 gauge and the wire for the 240 is #10 AWG. The previous owner seemed to have no issue by just using a 60amp fuse in the house, running buried cable to the garage, and from there into a junction box and out to two different style 240V outlets. When the house was for sale I remember seeing the previous owner had about a 30 gallon horizontal air compressor(sears I believe) and a hobart 235 stickmate. After searching the net for stats on those specific items he had I found the welder is o.k. with minimum #12AWG wire and the only thing on the compressor I could find was that it should be a 5 or 5.5 horse that requires about a 20amp fuse. My equipment is almost the same size as what he had. I'm no expert when it comes to electrical work so I don't know if this current setup is waiting for failure or is ok how he had it.
My compressor is a 13.1amp 230V unit and my largest welder says it requires a 50-70amp fuse says input voltage of 230V as well. The way I was thinking about setting this up is by hooking the wires in my house into the service panel with a 70amp fuse and in the garage installing a subpanel with two circuits, one for the compressor(20amp) and another for the welder(60amp). The 120 wiring I was just going to leave as is since it seems ok and I don't mind walking to the house to flip the breaker if it trips. Garage #2 is only about 40 feet from the main panel. Does this sound like an ok setup? It's better than what the previous owner had and the house and garage didn't burn with his setup.

 

[Tencubed]

I'd suggest protecting yourself, your insurance and your buildings.

Different insurance companies, inspectors and building departments require, or interpret codes, differently. You would do well, in my opinion, to have a licensed electrician check this out. It probably will not have to be inspected since it's just a re-do of previous work.

Hopefully you and your Dad had a permit to change the fuse/breaker box.

Mike

 

[John Garrison]

Of course we did since he himself was a liscenced electrician and we did everything by the book. That is why he left the wires disconnected from garage #2 until he could get a chance to upgrade it with me according to code. It worked the way it was before but he liked to have everything up to code. But to answer my question regardless of code, does that sound safe the way I planned on wiring it based on my compressor and welder stats I gave you? My welder draws more amps than my compressor and the welder requires a 50-70amp fuse so shouldn't a 70amp fuse at the house to a subpanel with a 20 and 60amp fuses for the said equipment be sufficient? I know codes vary but based on requirements for function alone, doesn't that sound like it would work? These units won't be on at the same time nor would they be taxing their duty cycles.

 

[jdrobison]

look at it this way, # 10 wire is good for up to 30 amps, and 14 is usually rated at 15 amps. I would not fuse the # 10 any higher than 30. if you put a 70 amp breaker on it you will burn up the wire before you trip the breaker if you ever exceed 30 Amps for long periods of time.

If the conduit is big enough pull # 3 wire to the shop and use a 100 amp breaker at the house and a 100 amp sub panel in the shop. if its no more than 40 or 50 feet this would be fine.

 

[vartz04]

You can only have 1 power feed to an out building. Welders can generally be breakered at half their rating (60amp welder gets 30amp breaker)

If you don't want to replace all of the wire run the 10ga to a small subpanel. Then you can run a light circuit a outlet circuit and a 220 outlet. Hook the 10ga to a 30 amp breaker in the house

Sent from the MTF Free App

 

[OKIE BILL]

I would probably use the wires already there and build a 30 amp sub panel. The thing is you can't power a sub panel the same as your 220 ckt. To power a sub panel safely you need four conductors. Two hots, a neutral and a ground. I would use the existing 14 ga. twisted together for a neutral, and the ground in the 220 ckt and the 110 ckt. twisted together for a ground. Remove the strap between neutral and ground in your new panel, and don't wire a second driven ground at the garage. I don't know what the inspector would say about my method, but it's as safe as can be and will do all that you need until your compressor kicks on while you are striking an arc.

Bill

 

[WNYTractorTinkerer]

So a one wire 220V feed? unusual.. :swow:

Usually single phase 230 V is acheived by hooking two 115 V wires (line to line) Each wire measured to ground is 115 V.. It's unusual in a residential setting to have such an electrical set-up.. It's more likely that the 220 V is the two wires and the ground is the 3rd wire. Get a electric tester and check it out or get someone who knows what's up.. :hide:

You will need another Ground stake @ the outbuilding along with a Neutral Stake for the 115 V (most likely- check local codes)

Something seems amiss.. Unless I'm missing something..:hide:

 

[John Garrison]

So a one wire 220V feed? unusual.. :swow:

Usually single phase 230 V is acheived by hooking two 115 V wires (line to line) Each wire measured to ground is 115 V.. It's unusual in a residential setting to have such an electrical set-up.. It's more likely that the 220 V is the two wires and the ground is the 3rd wire. Get a electric tester and check it out or get someone who knows what's up.. :hide:

You will need another Ground stake @ the outbuilding along with a Neutral Stake for the 115 V (most likely- check local codes)

Something seems amiss.. Unless I'm missing something..:hide:

I think you missed something. It's not one SINGLE wire for the 240V it's one #10 AWG cable and inside that cable is the FOUR wires for the 240.
I always thought that #10 cable should be used with a 30amp breaker so that is why I'm confused.
My manual for my welder says:
235amp A/C welder

-Input voltage: 230

-Input amperes at rated output: 47.5

-Max recommended standard fuse rating in Amperes: Time Delay-50A
Normal Operating-70A

-Minimum input conductor size in AWG: 12

-Maximum recommended input conductor length in feet: 87

-Minimum grounding conductor size in AWG: 12

So why would they recommend setting this up on a 50-70AMP breaker with a minimum #12AWG if #10 is only good for 30 amperes?

I think I should add that this is only a 20% duty cycle welder.

 

[WNYTractorTinkerer]

Sorry I missed that 'cable' part- Here's what I read:
Garage #2 is setup up as follows: There is one 220V wire along with one 110V wire buried together in underground conduit going from house to garage. Kinda confused me.. :dunno:

You have to wire the equipment to handle the highest power needs of the equipment or you run the risk of overloading or heating up the wires.. Even though you may never actually use that much power ever when you do use it, there IS that possibiliy.. The great thing you have going for you is the fact that it is buried in conduit and you should be able to pull some larger wire through as long as the conduit is large enough for the wire's size.. A 60 amp sub-panel should handle everything you need to use in the shop.. Plugs, Lights, Compressor, Welder, etc..

What size is the conduit you have buried? You just may have to keep the welder in Garage #1 and everything else can go out to #2 if it's too small.. As was said running two power circuits out to your garage #2 is just an accident waiting to happen.. Don't tempt fate.. JMHO :dunno:

 

[John Garrison]

Sorry to cause confusion and no offense, but I didn't think anyone was going to think I meant ONE single wire was ran to complete a 220 circuit seeing as how that is impossible. I am aware of the basic fundamentals of wiring such as the wiring needing to be of proper size and rating as the devices you intend to run on such a circuit. However, with the stats I gave about my welder, I find the information to be confusing. I don't imagine a company would give harmful information in an owners manual that could potentially lead to injury or loss of life and risk the lawsuits that would follow such a situation.
As for the dangers of running two circuits out to my garage, I'm not sure what danger you are refering to? I mentioned that there was one 120V wire(#14 cable) buried in the proper conduit and then there was another #10 cable in the same conduit with it. Both of these wires were wired into the house fuse box into SEPERATE circuits. The 220 was not achieved by hooking two seperate 110 circuits together. I don't see how a 110V cable properly fused at the house and ran out to the garage and a seperate 220V cable fused at the house and to the garage in the same conduit is an accident waiting to happen?
If anyone with extensive electrical experience would respond to the information I listed about my welder and the current wiring I have I'd appreciate it. My thanks to those who have taken the time so far to help.

 

[vartz04]

That rating is for welders only. You can't figure regular circuits like that. A welder circuit s usually 2-3 times the breaker size you would normally have on that size wire. That is because of the duty cycle of the welder. Wires need the current to be too high for some time to cause damage so they figure that into the welder breaker sizing.

As far as the two power feeds it's against code. Also dangerous if someone thought they shut off all power to garage but a second feed was still live.

I suggest you install it to code or pay someone else too. I've been shocked too many times working in houses where some hack thought they might know how to wire something halfway right. You really need to pull 2 #6 and 1 #10 depending on the distance. Then you can use that to feed a 60 amp sub panel. From there Install a light circuit (15amp) an outlet circuit (20amp) and a circuit for your welder.

Sent from the MTF Free App

 

[OKIE BILL]

John, Forget about my conductor sharing scheme. I didn't realise you already had a four wire 220 ckt, was thinking three wire. Your confusion in conductor size comes from comparing two different items for minimum and maximum on your welder. You wouldn't use use the minimum conductor size 12ga. with the maximum breaker size 50 or 70 amp together. You have enough copper for a 30 amp sub panel. Use the 14 guage for a phone or intercom ckt. Around here the rule is one driven ground per meter, at the meter. If you don't want to get an inspector involved, go check out someone else's sub panel.

Bill

 

[John Garrison]

I have also been gathering supplies to build another workshop. I have been thinking about just leaving garage #2 for storage and just building a 12x12 building strictly for work(no storage I hope) near the back of my house about 15-20ft. from the main service panel. This way I can just leave the previous owners 220V wiring unhooked from my main breaker but hook the 110V wire into my panel so I can at least have lights out in the storage garage #2 so I don't need a flashlight every time I go out there.
So, forgive my ignorance but what all should I need to run my compressor and welder in a building that is about 20ft. away given the equipment stats I listed?

This is what I think I'm going to need:
-60amp breaker in house main breaker panel
-about 25-30ft. of #6-4 wire(must be water rated) to connect the main panel to a sub panel in the garage.
At the sub panel:
-1 50amp two-pole breaker for the welder
-#10AWG to run from 50amp breaker out to my welder outlet(my welder manual recommends at least #12 wire so #10 should be fine)
-1 30amp two-pole breaker for compressor
-#10AWG to run from 30amp breaker out to my compressor
-I will then just add some 110V with 15 or 20 amp breakers in sub panel so I can install some outlets and have some lighting.
-#6 ground wire from sub panel to grounding rod at garage
I didn't mention the parts list but I will be sure to bury the cable in the right conduit, at the right depth, and use the proper connections to make my install weather tight and up to code.
I have a relative who is a liscenced electrical inspector who can sign off on my work. I would have just asked him but I can never get ahold of him since he is always in the Bahamas, Hawaii, or some other place warmer than here.
Does my list sound about right?

 

[WNYTractorTinkerer]

Please don't take it that I was 'dissing you' but I was trying to understand clearly what your dad had done there.. :hide:

BTW- You can transform incoming power to 440 V single phase or 220 V per leg.. (one wire) You can do just about anything you need to do with electricity via transformers- OK? It is an option and is possible! :dunno:

For instance- If you use a 480 3 phase wye transformer you will have 277 V to neutral on each leg but 480 V 3 phase with all three hooked up..

Looks like you are on the right track with your information above..

 

[John Garrison]

Please don't take it that I was 'dissing you' but I was trying to understand clearly what your dad had done there.. :hide:

BTW- You can transform incoming power to 440 V single phase or 220 V per leg.. (one wire) You can do just about anything you need to do with electricity via transformers-

I'm aware of the possibilities of transformers and have played with them over the years but I have no interest in doing that in this case.
So to beat a dead horse, I was planning on installing a 100amp subpanel in my 12x12 shed(once I build it!). I already have a 100amp Square D subpanel(this has no spot for main breaker) so that is what I plan to use. Anyway, the most power at once I will be using would be a 20% duty cycle welder that requires a 50amp fuse and maybe a fan and some lights at the same time. I will also be installing another 220V 30amp breaker for my compressor but that wont run at the same time as my welder so my power needs are not that extreme. Since I'm only installing this 20ft. max from the main panel and I won't be drawing that much current, I figure #6 gauge cable will be sufficient for connecting the main panel to the subpanel in the garage. However, a few sources I've talked to(none were licensed electricians BTW) all hear that my subpanel is a 100amp box and they all insist that 100amp box=#2 gauge wire and they insist #6 will burn up. Yes the box is 100amp 6 circuit capable but that doesn't mean I'm going to have a 220V welder, 220V compressor, numerous power tools, and all my lights on at the same time. With a 60amp breaker in my house main panel feeding my garage subpanel to a 50amp breaker for welder and a 30amp breaker for compressor, I don't think I'll be taxing anything. Sorry to keep this going. I know some of you are very experienced on this topic and it must seem like I'm fairly ignorant but I can assure you I'm skilled in many other fields but wiring is something I require visual instructions.... or else written instructions that are clear and exact.
Can someone let me know if my route will be fine or should I consider the #2 wire route?

 

[WNYTractorTinkerer]

A 60A breaker in the feeder and #6 should work fine.. (It's exactly what I have in my set-up in my shop!

 

[John Garrison]

I found three potential wiring options and I was wondering which is the best?
Way out here in the boonies there aren't too many stores available so the nearest one that carries electrical supplies is going to have to be my only option if I want to get this done quick. I found 6-3 UF(underground feeder) which will work fine but it's $4.30/ft. My other two options are 6-2UF for $2.85/ft. and 4/0-4/0-2/0 URD for only $1.90/ft.
I don't really know why the heavier gauge stuff costs LESS but since it is, shouldn't I just install the heaviest stuff I can? My main two concerns are, should I run the heaviest wire for the money and will the larger wire for $1.90/ft. be too large to wire into a 60amp fuse in the main panel?

 

[John Garrison]

So I ended up finding some 2-2-2-4 URD for $1.42/ft. so I went that route. It may be overkill for how little amps I'll actually be drawing but it's better to go bigger now in case I want to upgrade later. I just got the lug adapters to fit the #2 wire into the ground bar and neutral bar and bought some 1-1/4" PVC conduit to bury it in even though it's direct burial wire. If it'll ever stop raining I'll start augering some holes and dropping in some poles to start this workshop project. Now that I got the electrical parts I need, that will give me all the more motivation to knock this project out of the park.