Any electricians in the house?

[JasonB]

I just built a 12x16 outbuilding that I want to run electricity to. To get to it, I'm goingto have to run 150 or so feet of wire, probably 220 to the building and split it to 110 leads (unless 2 110 leads would be better?. The load there will be a 5hp air compressor, occasionally a 110 welder, and normal shop tools (tablesaw, etc. but never over 1-2 at a time). I will then run a lead from there (off one of the 110 leads) about 100' to put an outlet in the Carport I store my boats in to run a couple lights and battery charger.<br /><br />I plan on putting one of the shop type small breaker boxes in the building. What gauge wire shoud I use for the 220 and 110 legs? What size breaker to use in the house panel? I'll have to double check, but I'm pretty sure there is 60 or more amps of capicity left in the house panel. I will be using conduit to bury it in.<br /><br />I'll have someone with experience connect it to the panel, but I want to get it all buried before hand and ready for them to just hook up.

 

[heyttown]

Re: Any electricians in the house?

If you think you have the space for a 60 amp breaker, go buy a main breaker panel...probably have to buy 100 amp panel and replace the breaker with whatever size you feed it with.(Im not sure they sell a 60 amp main breaker sub panel)<br /><br />The best thing you can do is plan for the future,its better to go bigger on the wire size then smaller, that case being If you go the route of a subpanel(100amp) pull the correct size wire for 100 amp which I think off the top of my head is #4 thhn possibly #2 copper.<br /><br />Always oversize your conduit, its better to have overkill, then not enough freeair space and the conductors either wont pull through or will get extremly hot and burn.<br /><br />Im sure you'll get several good opinions on this site,as always choose what best fits your needs....I tend to go the extreme and try and plan as far ahead as I can.

 

[JasonB]

Re: Any electricians in the house?

Thanks Heytown. In my old shop, I had two 15 amp 110 leads, and they were ok. I was thinking about maybe a 40 amp lead so I would have two 20 amp leads, which would really be a minimum as 20 amp is what my two heaviest tools draw. Two 30's would be nice though. I have to be careful as there is one more 20 amp lead I need to pull if I have the capacity for a fish pump pong/future swimming pool.<br /><br />Any idea where one can find a chart for wire size/amperage/distance?<br /><br />Edit: found a calculator for it: http://www.powerstream.com/Wire_Size.htm

 

[sangerwaker]

Re: Any electricians in the house?

The only additional costs you will have if you go larger is the wire and slightly more for conduit and fittings. I would suggest a 60 amp sub panel. Put a 60 amp breaker in your house panel, run 1-1/4" conduit, and #6 AWG wire. Get a 8-12 circuit sub-panel, and put an additional 60 amp breaker in there. Feed into the 60 amp breaker at the new panel. That will serve as a disconnect means at the new panel. <br /><br />If you would ever upgrade to a 240V welder, this set up will have you covered.<br /><br />Your next decision will have to be whether to ground the new panel to the house panel, or drive a new ground rod to ground the new panel. If you ground to the house panel, you'll have to pull a 4th wire (doesn't need to be #6) inside the conduit to the new panel and use a gound bar inside the new panel to tie all of your grounds to. I'd recommend a #8 for that application. <br /><br />Is the person helping you a licensed electrician? I'd ask their recommendation if he/she is.

 

[crab bait]

Re: Any electricians in the house?

don't go below 60 amp.. but i'd go 100 amp.. <br /><br />you don't have to upgrade your house service even if'n it's only a 100 amp service..<br /><br />you overkill your shop..an never havta worry again.. as you grow ( an you will )your shop service will always be adequate.<br /><br />i think # 2 copper / # 1 aluminum for 100 amp.. but that mite be for 'free air' an not in pipe.. <br /><br />must have 3 wire an a ground for a sub panel.. like black,red, white ( for nuetral) an ground..<br /><br /> ( any panel after the main metered panel is a sub panel ) <br /><br />a property can only have one main panel but can have infinity sub panels <br /><br />get a 100 panel with 100 amp main breaker.. <br />an YOU MUST BUY (it's cheap ) BUT YOU MUST BUY A GROUND BAR for that panel.. YOU MUST..!!<br /><br />an screw it to the panel... <br /><br />all white wires go to the factory ( insulated from panel housing ) bus bar.. <br /><br />all grounds go to the newly installed ground bar..<br /><br /><br />by code..<br /><br />rigid gav conduit can be buried at 6 in depth.. <br /><br />pvc must be at 2 foot.. <br /><br />100 amp wire,, 1 1/2 dia. conduit.. <br /><br />off the record.. if you get 1 1/2 pvc down a foot,, you'll be good..

 

[sangerwaker]

Re: Any electricians in the house?

Crab,<br />I was always told you didn't need a ground bar at the sub panel as long as a seperate ground rod was driven and the sub was the only thing grounded to it.<br /><br />True or hogwash?

 

[JasonB]

Re: Any electricians in the house?

Thanks guys! This shop won't expand much if any as I plan to build a 2-3 car garage in a few years to become my permanent shop, just don't have the green to build the big one yet.

 

[JasonB]

Re: Any electricians in the house?

I was looking at something loke this for the shop: <br /><br /> http://www.lowes.com/lowes/lkn?action=productDetail&productId=34526-76863-TLM812SCUD&lpage=none <br /><br />OR this since my main box is Cutler-Hammer:<br /><br /> http://www.lowes.com/lowes/lkn?action=productDetail&productId=95541-82364-BR816L125SDP&lpage=none

 

[heyttown]

Re: Any electricians in the house?

Even though you dont plan on expanding, the 2 or 3 car garage would be enough to eat up a 100 amp panle right there........So like I said go with the 100 amp panel and when you do have the green to build the garage the power will already be out there......I would go with a 60 amp panel at least, but for the price you can get a 100amp main breaker panel for around 40 bucks at you local do it yourself shops(lowes/homedepot)<br /><br />As stated anything after your first "main" panel (in the house) anything after that has to have seperate grounds an neutrals through the entire panel.<br /><br />Even though you may only need 2-20 amp circuits now, you will need more in the future, and plus having a subpanel in the shop/garage helps to resell the house if that were to ever happen.<br />I have a 2 1/2 car garage and I put a 30 space 100amp main brkr panel in and its more then half full already,but at least I have room for more expansion.<br /><br />EDIT: I wouldnt put metal conduit in the ground to save time not having to dig as far......eventually that metal conduit will rust through and create more problems then they are worth....Go with PVC,easier to work with and faster (after the trench is dug of course)

 

[JasonB]

Re: Any electricians in the house?

I'll be going PVC and renting a trencher for sure.<br /><br />The separate ground is no problem.

 

[crab bait]

Re: Any electricians in the house?

yeah,, natl' elec code says you CAN'T have multi/more then one ground rod seperate of one another.. <br /><br />you can have a zillion rods driven.. but they all must be bonded together by an adequate wire jumper.. <br /><br /> i'm not up on the lastest code changes..<br /><br />guy at work is..we were talkin' oneday,,i said i have a rod driven at my shed..an ofcourse an exsiting one at the house..<br /><br /><br />side note::<br />main panel at house.. 3 wire an a ground ran to shop..<br /><br /> one end of ground wire connected to main panel ground bus/bar.. <br /><br />the other end ,, to the subpanel ground bar.. separate ground wire of the same size from subpanel ground bar to the shop driven ground rod.. i.e. one ground rod system cause there both bonded electricaly together.. <br /><br />he says the code now wants/only requires one ground rod per house,, now..<br /><br />no need or want to drive another ( shop) rod, code says.. cause they want all faults to go exclusively back to the main panel ground.. <br /><br />so in short.. no need for a secondary ( shop ) ground rod.. <br /><br />WHEOW..!! I'M WORN OUT..

 

[sangerwaker]

Re: Any electricians in the house?

Thanks crab! That must be one of the 2005 updates and I was not aware of it either. Looks like I'll be selling more ground bars!

 

[CalicoKid]

Re: Any electricians in the house?

Code is a bit different from state to state depending on what's been adopted. Here we drive TWO rods at the main panel and one additional at each outbuilding, all bonded of course. The reason is possible potential differences in the ground at seperate buildings. Also here we bury PVC conduit at 18 inches and UF cable at two feet. Make sure you're following the local rules.

 

[heyttown]

Re: Any electricians in the house?

Wow 18" isnt very deep if you have a frost line deeper then that.......Jason it wouldnt hurt to make a call to your local inspectors(if you have them) or find what the local code is. it could save you some time on the trenching and cost of extra ground rods.

 

[JasonB]

Re: Any electricians in the house?

I'll check the local codes.<br /><br />Frostline isn't a problem here. We bury pvc water lines at 12"-18" and I haven't seen one freeze in my lifetime, even where the last one we did was only 6" at one spot.

 

[Bondo]

Re: Any electricians in the house?

I'm Not an Electrician,..........<br /><br />So,... My Question is;...<br />How are you going to run a 150amp Welder on a 60 or 100amp circuit ??????

 

[heyttown]

Re: Any electricians in the house?

A 150 amp welder doesnt use 150 amps to operate....Read the nameplate on the welder and it will list the Current Draw or ampacity of the welder.

 

[Paul Moir]

Re: Any electricians in the house?

Exactly. A friend of mine has a shop in his garage powered by a 30A sub-panel. One of the tools is a 150A stick welder. Actually, there's some pretty serious woodworking tools in that shop - 240v table saw, jointer, planer, etc, plus probably 1000w or so of incadesent lighting. It's never a problem since there's never more than one or two tools running at a time. Or no other when the welder is running. <br />I think the only reason he went with 30A is that direct-bury (NMW) #10 is easy to find and his run was short.

 

[JasonB]

Re: Any electricians in the house?

The welder generates a max of 90 Amps and has a rated input requirement of 115 volt, 15 Amp, single phase. It is a small, inexpensive wire welder I have to play/learn with.<br /><br />My guess is that my 5.5hp, 27gal air compressor has a higher sustained load than the welder.

 

[90skichallenger]

Re: Any electricians in the house?

If you do as these guys suggest you will be right on.. One thing though. In my state items installed by the homeowner do not have to have a permit. However your state might require a permit to do that kind of work, check into it wouldnt want ya to get hung-up.<br />Later