Similar Shop Electrical Question
I’m doing the same thing Mr. T is. Running a line out to the garage for a subpanel.
I’ve got to cut through a poured concrete driveway to get there. Only a 15 foot run, but once I get there, where do I put the ground rods? Can I bury them in the trench with the conduit? If so, I’ve got the conduit coming out of the ground, into the garage and then the ground wire coming out of the garage and into the ground and then back into the garage again? I think I’m missing something. Excuse my ignorance.
Another question: I’m in one side of a duplex. The electrical panels are separated between the units, each with a meter base. There is no main shut off for either panel. How do I cut off the power in order to wire in the feed for the subpanel in the garage? Don’t say very carefully.
Thanks for the input.
Replies
I'm not an actual electrician, but every time I've done a sub panel it has fed through a breaker in the main panel rated for the size of the sub panel; i.e. a 60 amp double. So, you don't need to power down the whole panel to install it. Just turn off the main disconnect, wire the feed to the breaker and then snap it in. If you do have to shut down the whole panel, you just pull the meter. Not you personally. This should be done by your utility since the seal needs to be replaced. If you cut the seal and pull the meter yourself, you still have to call the power company to have the seal replaced. They're usually not happy when a homeowner does that. I have seen ground rods buried horizontally in trenches. I don't know how how deep they have to be, whether you need two rods, and separation to conduit.
cant you tunnel under the driveway instead.
I can't tunnel under the driveway because the original panel is on the side of the house with the driveway poured right up to it. Then some distance down the driveway is the garage. So, I need to go down from the panel into concrete and then travel to the garage wall which is also butted up against concrete. I could possibly cut two large holes on either end and try to tunnel, but feel it would be easier in the long run to dig it all out.
I know that I can bury the ground rods horizontally or at an angle as you have said. Just not sure of the distance from the conduit or how the ground wire travels. Out of the conduit into the garage, out of the garage into the ground and then back out of the ground into the garage? All of that exposed to the elements? I know it's not that important as long as there isn't a downspout right on it, but is this right?
I've got an electrician I can call on, but wanted to be able to call him in when I really get in a bind. Rather than in the planning stages.
Workinhard,
Have you cut and removed concrete before? You don't want to know how deep you're supposed to dig under a driveway.I'm just asking because it is a SOB,and even if you had to travel 6x the distance to go around it,it would still be a lot easier.Is an overhead feeder out of the question?
The size of the equipment grounding conductor you take out to the garage depends on the size of the overcurrent device ahead of the circuit.If you're feeding the garage with a 100 amp breaker you'd need a #8 ground,with a 60 amp feed you could pull a #10 ground.You should terminate the ground wire in your service panel on the equipment ground bar and the other end of it on the the equipment ground bar in the sub-panel in your shop.Under another screw on the the shop ground bar,take another ground wire,this one called the grounding electrode conductor, out to the ground rod(s).Where I live the inspector lets the second rod slide on a garage.I don't care for the idea of laying them in the trench,I would drive them(6' apart if you use two).The smallest size grounding electrode conductor you can use is a #8.This can be run exposed.You know you have to have the neutral isolated from the EGC in the sub-panel,right?
Barry
Yeah, thanks for the info. I'm aware of separating the ground from the neutral in the subpanel. Makes sense on bringing the ground from the panel out to the ground rods. I'm dealing with a backyard that's entirely paved. I mean every square inch, so I don't know where I would go that wouldn't be under concrete. The area I'm planning on cutting through wouldn't be where cars drive on (it's about a foot wide of the garage doors). So, I'm hoping I would dig about 12 inches deep and then fill and patch the concrete. I've got to check code - it's technically the driveway, but nowhere a car will go.
I don't know less about overhead feeds than I do about underground, so if you can enlighten me, I'd appreciate it. If I could run overhead, it would save a ton of labor.
I'm trying to run a table saw (rated at 5.6 amps @ 220v), Lights, and hand power tools around the shop. Maybe a Mig welder in the near future. I never have had occasion to run more than one tool at the same time, except a dust collector and whichever tool is running. I was thinking a 60 amp panel would be plenty. Make sense?
Try talking to your utility and your local inspector. You may be able to have the garage put on its own service, i.e., a separate meter for that structure.
I wish my backyard was concrete, I hate cutting grass.
Go ahead with a 100 amp subpanel. really not that more money and have plenty of power. like today I was running cracker box welder, grinder, fans, and the aircompressor kick on couple time, plus lights. winter might want some heaters.. It really only couple dollars more., just the wire and couple breakers.
I think for most home workshops,a 60 amp feeder will do fine.
As for the overhead feeder,you have to have 12' of clearance over a residential driveway.It might not be as pretty,but you could ask anybody that complains if they want to help you sawcut the driveway.
As for the parts,it's just like two services tied together overhead.Run up the side of the house with conduit and set a weatherhead and a porcelin knob.Do the same thing on the garage.Then run a piece of triplex (insulated conductors wrapped around a bare neutral conductor) between the knobs with strain relief fittings on each end.Then make your connections with split-bolt connectors and tape them up.Easier than it sounds.I'm pretty sure they would have all the parts at a HD or Lowes.
"Then run a piece of triplex (insulated conductors wrapped around a bare neutral conductor) between the knobs with strain relief fittings on each end.Then make your connections with split-bolt connectors and tape them up"
But what about the ground?
Is that available in "quadplex"?
Available with two or three insulated conductors.
Seems like aerial is the way to go for me. Probably only a 10 foot run overhead. Then the conduit to the box. Does the triplex (fourplex) run all the way to the boxes, or do I splice it on either side of the overhead run?
Use individual conductors(THHN/THWN) in your risers and coming out of the weatherheads 18".Leave the same amount on either end of the quadplex.As you make the splices leave drip loops so that water can't run back into the conduit/house.See Cliff Popejoy's description of making up split-bolts in his answer to Mr.T. I like to use 3M mastic pads for making up connections,then cover with Scotch 33 electrical tape.
If you're not sure about the strain reliefs that attach to the porcelin knobs,ask around.It grabs onto the bare conductor and will get tighter the harder you pull on it.The utility company may have one on the side of your house if you have an overhead service drop.
Edited 6/29/2004 10:16 pm ET by IBEW Barry