i would like to know if this is correct i plan to wire my shed it is about 100 feet from my house i plan to use a 30amp 2 pole breaker in the house and run 10/3 with ground out to a 70 amp max (got this for free) box this box holds two breaker slots i plan to use both . i want to put 2 - 20 amp breakers in the box to establish 2 circuts one for lights and one for four recepticles is i plan to run a ground from the box to the ground i dont plan on using anything big just some simple power tools and a couple small saws is this right

 

If the shed is detatched from your home, then you will need a disconenct at the shed (usually a main breaker in the remote panel), a ground rod at the shed, and keep the neutral and ground electrically isolated. For a 30A 100' run you should be ok with #10 but you might choose to go with #8 copper to reduce voltage drop.

 

Since you only plan two breakers (i.e., six or less), I believe that these two breakers can serve as the disconnect, without a main breaker in the shed.

 

john and ron thankyou for your input about my shed i think i made a mistake on the distance i needed to go i think it is 125 feet not 100 like i stated earlier would i still be able to use 10/3 with a 30 amp double pole if i had to go with 8/3 would that change the breaker size i need in the basement or the shed

 

What type cable are you planning on using ?

 

Two factors influence wire size: (1) breaker size, and (2) voltage drop. The code regulates the first, but only your common sense and good design principles govern the second. From code and safety points of view, 10-gauge wire is all you ever need on a 30-amp breaker, regardless of distance.

So now let's look at voltage drop. Good design principles say you should have no more than a 2% to 5% voltage drop (depending on who you listen to, and what kind of loads are involved).

125 feet of copper wire with 20 amps on each leg will have a 2.2% voltage drop, and only that much if you max out the two 20-amp breakers. If you add more later and use the full 30 amps, you still will only have a 3.3% voltage drop -- still acceptable by most standards.

So I'd say only increase the wire size if you think you'll ever need more than 7.2KW of power there.

 

john thankyou very much for your help i think ill just stick to 10/3 if i ever overload either of the two 20's it will trip the breaker in the shed only right and i forgot to ask do i need to go very far under ground with my wire its uf and nothing heavy is going to run across it i also did what you said and went out and got a grounding bar to keep the neutrel and the grounds seprate in the box in the shed i think i will also come off that grounding bar to a grounding bar ioutside the shed thanks for all your help wish me luck

 

I know this isn't what you want to hear, but you must bury that cable at least 24 inches deep.

 

john does it matter im using uf i really didnt want to go that deep and there will be no traffic on it

 

Yes, I know you don't want to go that deep. But you must.

Direct burial: 24"
In rigid metal conduit: 6"
In PVC conduit: 18"

Take you pick. Rent a trencher.

 

hey john ihave to wait 3 days to dig up my ground (call before you dig thing) so i thought i would start the inside first i want to put all three switches for three seprate controled lights in the same box can i attach black jumper wires on each of the three switches then wire connect them to the incomming black wire connect all my whites together and then connect each black wire from my outgoing cables to the remaining screws on their respective switches will this make each switch control its own respective light

 

Yes. Don't forget the grounding connections too.

 

ok i think i broke the golden rule i dont think i bought enough wire for my run is there any way i can put a junction in the basement and can i use regular 10/3 to finish going to my breaker box

 

No problem. As long as you make the splices in a permanently accessible junction box. Good to finally get some good news for a change, huh?

 

JOHN you should be getting paid for this the way you explain things down to our level is comendable one more question if i may how the hell do you get the wire through will that pcv gule hurt uf iplan on putting the wire through then glueing does that lube stuff really work oh by the way it only took me 8 HARD hours to shovel my required 18 inches 100ft long very tired oh well at least i know its done right thanks to you thankyou i would recomend you to anyone my wife thinks your a saint

 

Russell, I'm going to let somebody else handle that. There are people here with a lot more experience pulling wire through conduit.

But if I had spent 8 grueling hours with a shovel, I think I'd bury 2" conduit, with gentle sweeping bends, to make sure I never had to do it again.

 

Russell,


No the Pvc glue does not hurt the wire.

YESSSS the wire lube can be worth it's weight in gold. Use plenty!!! It also helps to Have a good helper keep the wire trained as it goes into the pipe (don't let it twist too much) Twisting doesn't hurt the wire only makes it harder to pull.
Good luck

 

I concur with John on the 2" pipe, it cant hurt. It will also make the pull a breeze.

 

HEY SPARKEY THE LUBE WORKED GREAT THANKS I HAD TO WORK IN BETWEEN RAIN DROPS BUT THE HARD PART IS OVER ON WITH ON WITH THE WIRING MARCERIN I WISH I WOULD HAVE WENT WITH THE 2 INCH OH WELL LIVE AND LET LEARN

 

I have a question on the same thread for shed wiring.

As I understand from the posts that for an outbuilding subpanel, the ground and neutral must be separated and that a ground rod must be used and connected to the equipment ground lug in the shed panel.
The question is; should the ground wire coming from the main power panel (e.g. from the house main panel supplying power) be connected to the ground lug in the shed panel? Essentially, this is setting up a ground 'loop'. Is that ok?

I have another question related to pulling cable through PVC. Can silicone spray be used on the cable jacket to ease in pulling or will silicone damage the jacket?

Thanks in advance.

 

YOU MIGHT WANT TO ASK JOHN ABOUT THAT ONE BUT IF I READ YOUR QUESTION RIGHT YOUR GROUND AT THE HOUSE SHOULD BE GROUNDED AT YOUR HOUSE WHEN YOU RUN YOUR LINE FROM THE SHED YOU GROUND IT TO THE GROUNDING BAR IN YOUR MAIN BOX WHICH IN TURN IS GROUNDED THROUGH A WATER LINE OR WHATEVER WHY RUN ANOTHER GROUND BACK TO YOUR SHED IF SOMETHING HAPPENS INBETWEEN MY SUBPANNEL IN THE SHED AND THE THE HOUSE THE GROUND IN THE HOUSE WILL TAKE IT IF SOMETHING HAPPENS FROM THE WIRES IN THE SHED TO THE SUBPANNEL THE SUBPANNEL GROUND WILL TAKE IT IM NOT GOOD AT EXPLAINING THINGS SO MABYE SOMEONE ELSE CAN EXPLAIN IT BETTER

 

Yes, the ground loop is okay.
Use cable lubricant.

 

HEY JOHN COULD YOU EXPLAIN WHAT NOSHOCKS MENT BECAUSE THE WAY IM DOING IT DOESNT SOUND LIKE A GROUND LOOP IM HOOKING THE GROUND WIRE FROM THE 10/3 IN THE SHED ON THE GROUND BAR IN THE SUB PANEL THEN THE GROUND FROM THE 10/3 IN THE HOUSE GOES ON THE GROUND BAR IN THE MAIN PANEL I STILL WILL RUN A GROUNDING ROD FROM MY SUBPANNEL INTO THE GROUND WHAT IM TRYING TO SAY IS THAT OK NOT TO HAVE A GROUNDLOOP WHY WOULD SOMEONE RUN A GROUND BACK OUT TO THE SUB PANEL THAT WOULD BE LIKE RUNNING WIRE WIRED AND GROUNDED FROM THE MAIN PANNEL TO AN OUTLET WIRE AND GROUND IT THEN RUNNING A GROUND FROM THE MAINPANNEL BACK TO THE OUTLET

 

I don't really know what noshocks meant. noshocks asked one of those questions that you don't need to understand in order to answer.

I have no idea if noshocks has a "ground loop" or not. All I'm saying is that it's okay if he does. I assumed that noshocks was referring to a situation in which there is a metallic path between buildings (e.g., a water pipe) plus a grounding wire. Essentially, the grounding wire and the water pipe might form a loop (or parallel path), if the panels were grounded to the water pipe at both buildings (as they should be).

If he is assuming that the earth (i.e., dirt) is part of the loop, then he's giving the dirt too much credit. It's not a very good conductor of electricity.

 

Sorry about the confusion.

I guess what I meant was (and typed it without thinking) was that if a ground wire were run between the house ground and the shed ground, the loop that's set up is indeed with the earth. I wasn't thinking of the earth as a particularly good conductor but that the shed ground potential is different than the house ground potential. Ground potential can be different from one point in the earth to the next. This difference of potential sets up the 'loop' as you now have a circuit.

I didn't mean to go so 'deep' here. I was just wondering what the accepted practice was for connecting grounds between buildings. Someone said it is ok to connect the 2 grounds (house ground with the shed). Do you concur?

 

in a 4-wire feed to a subpanel. Keep them isolated from each other. Neutral wire goes to the neutral bar (which is not bonded to the electrical enclosure) and the ground wire goes to the ground bar (which is bonded to the electrical enclosure). Ground rod is connected to ground bar in a detached building set up.

 

JOHN THIS SHOULD BE MY LAST POST FOR THIS SUBJECT I JUST WANT TO LET YOU KNOW THAT EVERYTHING IS UP AND RUNNING GREAT THANKYOU FOR YOUR ADVICE ON EVERYTHING I ONLY HAVE THREE MORE QUESTIONS TO THROW AT YOU FIRST WHEN I TOOK THE FACE OFF THE MAIN PANEL IN MY HOUSE I HEARD A FAINT BUZZ THEN IT STOPED THEN I HEARD IT AGAIN IS THIS NORMAL SECOND DO THE NEUTRAL AND GROUND HAVE TO BE SEPRATED AT THE MAIN PANEL WHEN I WENT TO WIRE IN THE MAIN PANEL I FOUND NEUTRAL AND GROUND TOGETHER THIRD I HAVE A 100 AMP SERVICE IN THE MAIN PANEL MY BOX IS NOW FULL I HAVE SEVERAL 20,15 AND FOUR 30 AMP BREAKERS IS THAT TOO MUCH FOR MY BOX I HAVE NEVER TRIPED THE MAIN WHEN SHOULD I UPGRADE MY BOX THANKYOU FOR ALL YOUR HELP GOD BLESS

 

1. Faint buzz is not uncommon. Check to see if all connections are tight.

2. Neutral and ground must not be separated in the panel with the main disconnect.

3. What is "too much" for one box cannot be determined by listing the breakers in the box. It is determined by other factors. Do you want to pursue that?

4. To release the caps lock, hit the "Caps Lock" key just above the left hand shift key. The period is just below the ring finger of the right hand.