Salty Cajun Folks With Electrical Knowledge

[swamp snorkler]

I want to run power to a work shop I built, it's 12'x20'. I'm going to put 4 sets of 4' flouresent lights with 4 bulbs each. I have a 2hp table saw, scroll saw, 1hp band saw, disc sanding station, air compressor, router table, a miter saw station and a table top drill press. Obviously all of that will not be running at the same time, at most possibly the air compressor, lights and another tool. My plan is to tie into my service panel 220 and run it to my workshop through the attic in my house. It's about a 100-125' run. I plan to use a 50 amp breaker and run it to a 110 sub panel then feed off of there. My question is what size wire do I need. Will 6/3 w/ground be enough or should I go to a larger gauge.

Could I use http://www.homedepot.com/p/Southwire...0002/202316279 and run it though conduit for about 8' from my attic to my shed?

[Reggoh]

If you are running a 120v sub panel you only need 3 wires (hot, neutral, gnd) and you will need a single pole 50A breaker.

If you decide to put 240v on the sub panel then you will need 4 wires (2 hots, neutral, gnd) and you will need a 2-pole 50A breaker.

#6 is the correct size for a 50A circuit.

[swamp snorkler]

So I only need 6/2 w/ ground?
That'll save some money.

Thanks Reggoh!

[paublo25]

Yeah only need a 6/2 w/ ground if you are only running 120V but I would recommend running the 6/3 w/ ground so you won't run into the hassle of trying to run an additional wire for 220v if/when you need it. I ran power to my shop last year and ran 2 power legs so that I could run my lights off one leg and everything else off the other leg. That way I KNOW that if I trip a breaker with a tool my lights shouldn't go out with it.


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[AubreyLaHaye458]

PM Marshrat on here. He's an electrician.


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[swamp snorkler]

Originally Posted by paublo25

Yeah only need a 6/2 w/ ground if you are only running 120V but I would recommend running the 6/3 w/ ground so you won't run into the hassle of trying to run an additional wire for 220v if/when you need it. I ran power to my shop last year and ran 2 power legs so that I could run my lights off one leg and everything else off the other leg. That way I KNOW that if I trip a breaker with a tool my lights shouldn't go out with it.


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Good point.

[MarshRat89]

Originally Posted by swamp snorkler

I want to run power to a work shop I built, it's 12'x20'. I'm going to put 4 sets of 4' flouresent lights with 4 bulbs each. I have a 2hp table saw, scroll saw, 1hp band saw, disc sanding station, air compressor, router table, a miter saw station and a table top drill press. Obviously all of that will not be running at the same time, at most possibly the air compressor, lights and another tool. My plan is to tie into my service panel 220 and run it to my workshop through the attic in my house. It's about a 100-125' run. I plan to use a 50 amp breaker and run it to a 110 sub panel then feed off of there. My question is what size wire do I need. Will 6/3 w/ground be enough or should I go to a larger gauge.

Could I use http://www.homedepot.com/p/Southwire...0002/202316279 and run it though conduit for about 8' from my attic to my shed?

By code you can't run Romex in a pipe. You would need to run 3 strands of #6 thhn and one strand of #10 green thhn wire if you want to run a 50 amp 220 volt sub service. 50 amp sub service should be plenty for what you are trying to run. You could even run a small welding machine if need be.


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[Lake Chuck Duck]

I just did almost exact same setup and run to my shop. I ran 6/3 to my panel in the shop just in case I ever need to add a 240 plug.

[latravcha]

Damn I must believe in overkill. I ran 3 stands of 2 to my shed. I had a ground rod already there so that saved me one run.

[Reggoh]

Originally Posted by paublo25

I ran power to my shop last year and ran 2 power legs so that I could run my lights off one leg and everything else off the other leg. That way I KNOW that if I trip a breaker with a tool my lights shouldn't go out with it.

It is a good idea to run all 4 wires and put in a 240v sub panel. This is why I suggested it in my original answer.
It leaves room to grow your future electrical needs and wouldn't cost much more.

With regards to putting all of your lights on 1 leg by itself... That is not necessary... if you trip a "breaker" only that breaker will shut off... if you overload 1 side (or leg) in your panel the entire panel will shut off at the main breaker in that panel or the 2-pole breaker that it was fed from.

Your main or sub-feed breaker should be a 1-Throw breaker by code. If 1 side trips the other side will shut off with it because they are tied together.

A panel like this is what I put in my shop off of a 50A breaker in my main panel.
http://www.lowes.com/pd_105719-76863...ectrical+panel

[keakar]

last I was aware, the electrical residential wiring code called for only 3 wires, two main wires and a ground wire (often slightly smaller sized) so this is why everything 220v "inside" the house is running off or 6/2 with ground or 8/2 with ground romex.

for safety they use an extra main wire connected to the exterior panel ground lug is why you need 3 main wires when running under ground out to a shed or separate garage? its just extra safety in case there is a problem with the grounding rod for the shed or garage.

[swamp snorkler]

Appreciate all the input.

[keakar]

Originally Posted by swamp snorkler

Appreciate all the input.

by the way, running over 100 ft (if that's from where it exits the house) you might want to run three #4 wire with a #6 ground, especially if you think you might want to run a welder or something needing a lot of power. always go bigger then you need so you can expand later.and use one side for half of your power tools and put the other half your power tools on the other line so your not running everything off of only one wire. the ground shouldn't be more then one size smaller then the main wires.


the idea of running the lights separated is good but I would run the lights for one half the shop on one wire and a separate switch and wire to the lights for the other half.

the key is to keep your loads balanced equally on both wires as best as you can

just as an example I am running something like you with it feeding off my main panel on a 60 amp breaker feeding a 50 amp breaker box at the back of the house and running three #6 wires with a #8 ground running underground out to the garage that is only 30 ft away from where it exits the house and a total of 75ft from the main panel. it will just be for wall outlets and lights. once inside the garage it will connect to a 60 amp 4 breaker panel, two for lights and two for outlets, one each for each side

Originally Posted by AubreyLaHaye458

PM Marshrat on here. He's an electrician.


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this is the best advice ^^^^^^^^^^^^

its been a while since I was up to date on the latest wiring codes and you want to get this right.

with the tools you talk about running in your shop, the best idea might be to not go through the house at all and just run a completely separate 100 amp meter and service to the garage because the load on your house panel may not be adequate to run the garage even though you have space for the breaker.

[Reggoh]

Originally Posted by keakar

last I was aware, the electrical residential wiring code called for only 3 wires, two main wires and a ground wire (often slightly smaller sized) so this is why everything 220v "inside" the house is running off or 6/2 with ground or 8/2 with ground romex.

for safety they use an extra main wire connected to the exterior panel ground lug is why you need 3 main wires when running under ground out to a shed or separate garage? its just extra safety in case there is a problem with the grounding rod for the shed or garage.

The appliances in your home that you are talking about (hot water heater) are dedicated 220v and only require 2 hots and a ground... a sub panel in a garage or shop needs the 4th wire for a neutral so you can run 120v.

220v needs 2 hots and 1 ground
120v needs 1 hot, 1 neutral, and 1 ground

If you need help send me a PM... I'm not an electrician but I did stay at a Holiday Inn express last night.

(Just kidding... I am an industrial electrician so some of the residential guys may know a little more about code than I do but I'd be glad to help if I can)

[keakar]

Originally Posted by Reggoh

The appliances in your home that you are talking about (hot water heater) are dedicated 220v and only require 2 hots and a ground... a sub panel in a garage or shop needs the 4th wire for a neutral so you can run 120v.

220v needs 2 hots and 1 ground
120v needs 1 hot, 1 neutral, and 1 ground

If you need help send me a PM... I'm not an electrician but I did stay at a Holiday Inn express last night.

(Just kidding... I am an industrial electrician so some of the residential guys may know a little more about code than I do but I'd be glad to help if I can)

well yes but in 110v the neutral and grounds are both connected to the same ground bar feed by one common main ground wire so as far as feeding the panel you only need 2 hots and 1 ground weather you run 220v or 110 off of it. I know they changed the rules on indoor appliances so you run 3 conductor plus ground to driers and stoves and such so you have two dedicated grounds for 220v just like you have for 110v but not to attics or exteriors boxes like central heaters or outside power to a/c.
as far as main wires feeding the panel goes, when a shared meter and breaker panel is used to power an exterior building, I am only aware of using 3 conductor plus ground so that the third conductor acts as a main grounding wire in case the grounding rod for this exterior building should fail.

but I haven't done residential wiring in a long time so im sure they may have changes to things I am not aware of.

I do notice the large amount of tools he wants to run, while he says only one at a time, he might be better with a separate power supply NOT feeding off the same meter and panel as his house because the "potential" to overload the power supply coming through the meter and main house panel is there. if he were careful he would be fine as long as he doesn't overload it. I just don't know what the limits are before code requires a separate meter or not to be honest.

he really does need a residential electrician to asses if he has unused power to run everything in the shop he wants to and to determine the distance involved to properly make decisions rather then guys like us that know electricity but may not be aware of all the latest codes and requirements. I used to do residential electrical for new houses for 20 years and it felt like they come up with new rule changes for it every few years. at this point, everyone in this thread is just assuming he has the power available to tap into his house panel but just because there is an open breaker slot doesn't mean you wouldn't be overloading the panel by adding it.

[MarshRat89]

Originally Posted by keakar

last I was aware, the electrical residential wiring code called for only 3 wires, two main wires and a ground wire (often slightly smaller sized) so this is why everything 220v "inside" the house is running off or 6/2 with ground or 8/2 with ground romex.

for safety they use an extra main wire connected to the exterior panel ground lug is why you need 3 main wires when running under ground out to a shed or separate garage? its just extra safety in case there is a problem with the grounding rod for the shed or garage.

Code still requires you to carry a ground from the primary service.


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[MarshRat89]

Originally Posted by keakar

by the way, running over 100 ft (if that's from where it exits the house) you might want to run three #4 wire with a #6 ground, especially if you think you might want to run a welder or something needing a lot of power. always go bigger then you need so you can expand later.and use one side for half of your power tools and put the other half your power tools on the other line so your not running everything off of only one wire. the ground shouldn't be more then one size smaller then the main wires.



the idea of running the lights separated is good but I would run the lights for one half the shop on one wire and a separate switch and wire to the lights for the other half.


the key is to keep your loads balanced equally on both wires as best as you can

just as an example I am running something like you with it feeding off my main panel on a 60 amp breaker feeding a 50 amp breaker box at the back of the house and running three #6 wires with a #8 ground running underground out to the garage that is only 30 ft away from where it exits the house and a total of 75ft from the main panel. it will just be for wall outlets and lights. once inside the garage it will connect to a 60 amp 4 breaker panel, two for lights and two for outlets, one each for each side


this is the best advice ^^^^^^^^^^^^

its been a while since I was up to date on the latest wiring codes and you want to get this right.

with the tools you talk about running in your shop, the best idea might be to not go through the house at all and just run a completely separate 100 amp meter and service to the garage because the load on your house panel may not be adequate to run the garage even though you have space for the breaker.

He would have to be fully loaded up drawing 55amps and a power factor of .9 for a voltage drop to become an issue. From the sounds of it he's running less than 80% of that. #6 should be sufficient. It Depends on the type of lighting if he goes with say 2 LED high bays he's only drawing about 300watt. Also, Code actually allows you to step down your neutral one size and the ground two sizes. The price difference is not that significant though.


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[swamp snorkler]

Once again thanks for all the info.

[ski]

Originally Posted by latravcha

Damn I must believe in overkill. I ran 3 stands of 2 to my shed. I had a ground rod already there so that saved me one run.

You need a low impedance path to ground. Your setup might just burn up. Ground should run back to the electrical service so that your breakers will trip properly. Check into it so you don't have serious problems. Neutral and ground can only be bonded at the point of service in Texas.

[keakar]

Originally Posted by ski

You need a low impedance path to ground. Your setup might just burn up. Ground should run back to the electrical service so that your breakers will trip properly. Check into it so you don't have serious problems. Neutral and ground can only be bonded at the point of service in Texas.

good catch, its the same here and he isn't up to code

nobody else caught where he said he didn't run a ground to the main panel.