So those of you that know me I sold the chickens and coop. You may remember the deal running electric to it..

Well anyway I have that breaker left empty that went to the coop. There are 2 20 amp breakers in this box. I would like to change the old coop one from a 20 amp to a 30 amp. Is that allowed?

Note: In the home is a 50amp GFI breaker powering this box at the shed..



I then want to run conduit outside along on top of the railroad ties I have boardering the shed and garden all the way to where the camper is parked.

Is this possible?






Its a total of about 75 ft.

I assume I can run 12 gauge wire instead of 10?

 

Yes..... you can change one of those breakers to a 30A breaker but you need to use #10 wiring since you are protecting the circuit at 30amps. The #10 will keep the voltage drop to a minimum also.

I'm not sure about the PVC at ground level. I think in your case I'd consider using schedule 80 PVC for max protection.

 

I thought I was allowed up to 10% voltage drop by code? 12 gauge @ 75 ft comes to 7.5% I think with a 30 amp load.

I dont understand this...?

 

There are two calculations, done independently of each other, for wire size. First is the voltage drop calculation which depends on length of the run (round trip) and amperes among other things. I think 5% voltage drop is the figure to shoot for. Second is the heat dissipation calculation, or in most cases picking the wire size given the circuit amperes rating from a table in the NEC. The latter yields 10* gauge for 30 amps.

You use the larger of the two sizes you come up with.

* When many wires are running parallel in close quarters, there is an additional sub-calculation which can point to a yet larger needed wire size, for use in the heat dissipation calculation but not needed for the voltage drop calculation.

 

I thought NEC assumes 167F..?

Where is this table? Does not the voltage drop of 7.5% supersede the chart? Im below 10%..

But I am not an electrician and you need to show me or speak in layman's terms somewhat...

 

Schedule 80 PVC and #10AWG THWN conductors. I would run the pipe up the end of the shed, then go around the corner and attach it above the door over to the garden end.. I'd also use two-piece straps fairly close on each side of the hubs to keep it from flexing there.

 

It's Table 310.15(B)(16) (formerly Table 310.16) Allowable Ampacities of Insulated Conductors Rated Up to and Including 2000 Volts, 60°C Through 90°C (140°F Through 194°F), Not More Than Three Current-Carrying Conductors in Raceway, Cable, or Earth (Directly Buried), Based on Ambient Temperature of 30°C (86°F)* in the 2011 NEC. Here's a copy from an earlier cycle that's still close enough to work from: NEC Table 310.16

Don't forget to read the footnote.

No. Nothing supersedes Table 310.15(B)(16). There are enough ancillary calculations and exceptions to make your head spin, but none of them applies to what you're planning to do.

 

In addition to what Nash wrote the NEC specifically limits #12 copper conductors to a maximum of 20 amperes regardless of any other factors. #10 is limited to 30 amperes and #14 is limited to 15 amperes. Larger than #10 is where temperature calculations are normally considered as well as other factors.

As for voltage drop...the NEC does not specify any maximum voltage drop but does recommend a maximum of 5%. Read this for more information than you really want. Mike Holt Voltage Drop Calculations

And definitely use the schedule 80 PVC conduit if you run it above ground. I personally would rather see it underground and even then use schedule 80 where it emerges from the ground.

 

The voltage drop calculation supercedes the table when it would call for a yet larger conductor. But this is a recommendation (the technical term is "should"), not a mandate (the technical term is "shall").

 

The foot note on that table notes small conductor.. Whats that mean...


But OK.. #10 wire it is...


Now its may be easier for me to run external.. But I was thinking of running from the box, then back into the shed with #10 romex. Right now for the shed circuit I have loose wire running into the shed to a box inside. Then its converted to romex for an outlet and light.

Do I run loose #10 into that same box, then come out of that box with #10 romex to the other side of the shed?

I would then put a box outside on the otherside of the shed and feed the romex through the hole and into the box?

From there I will run conduit as stated.. (Then it will be 50 ft to the camper)


I would like to run underground cable but its pricey. Plus I dont want to dig a trench 50ft long 18" deep...

 

Voltage drop on this is a non-factor. Your not even close to a distance that will have a significant effect.

#10 wire is required for your circuit because of the footnote already mentioned pointing you to 240.4(D) which lists maximum overcurrent protection for #12 copper wire to 20 amps, and #10 copper wire to 30 amps.

You can run either run #10 THHN or #10 Romex from your outside panel back into the shed. The THHN will need to be in a raceway while the Romex does not.

Inside the shed you can run Romex as long at it is not subject to physical damage, between studs or along the rafter framing. Then you will need to convert it back to THHN and conduit in a box, either inside or outside the shed, and run your PVC out to the RV.

Other options on digging is to install Rigid steel conduit. That you only have to bury 6" but also be a bit pricy. I think running through the shed is a good option.

 

OK so do I have to run loose #10 THHN from this box into the shed? ( In the shed there is a box.)




Once in here run # 10 romex to other side of shed?

 

No, You don't have to. But looking at your pictures you have no raceway between the inside box and the outside panel, or your missing a connector. That should be fixed as you have single wires running through there now.

I also recommend changing out the inside box to something larger. Either a 4"x4" box, or 4 11/16" x 4 11/16" (Also, called an 11b).

You also need a staple on your 12/2 Romex within 12" of the box. (pick,pick,pick)

 

Optionally you could run the #10 Romex from inside directly through the wall and into the box on the other side (the outside). Getting across the shed on the inside the Romex needs physical protection, typically you would staple it to studs at least 1-1/4" in from the stud inside and outside edges, up to the ceiling, then on or through joists at least 1-1/4" away from the top and bottom edges, etc.

 

I put a raceway. The second pic is old. You see in the first pic there is that plastic wire protector.. ( I forgot what I did inside but I believe there is a threaded fitting right into the box...)

OK I found the pics.. ( here is what I did.)

 

OK, here's the footnote:

The footnote reference mark - the single asterisk - is in the table at #14, 12 and 10AWG. Correction factors for ambient temperature and number of conductors (in a raceway) will require larger wire under certain conditions. They never allow smaller wire. The same is true of a voltage-drop calculation.

The W is important. It denotes water resistance. The good news is that almost all individual conductors are labeled THHN/THWN. Just double check.

I like your idea of running Romex through the shed to an outside box on the other end. Neater, cleaner, easier and less expensive - what's not to like?

Is it pricier than the same length of conduit plus three individual #10 conductors in three different colors?

Ah-ha! But don't you do trenching on a regular basis? I thought you either owned or had ready access to a trencher or back hoe.

 

Cobbler's children go barefoot! My Boss (Electrical contractor) hates to do wiring. Go figure!

Good to see you have the nipple installed. I still suggest you change that handy box to something larger. Adding 5 #10 wires will likely over fill that box.

 

Or can I run romex into it? If so then the romex will run in then out of the inside box...

 

Yes. If the cable just goes through without any connections in the box then you don't have a box fill issue. To make sure the box is grounded you can just run a separate ground wire through the nipple, if you didn't already do that.

 

What would that be? Right now just THWN goes from the other breaker into the inside box. Then wirenuts to romex and goes to the shed electric.

I am wondering why I ran THWN into the shed from the breaker in the first place if I could have run romex right to the breaker...

Confused to say the least.. But id like to stay consistant..

 

Wires that are terminated or spliced inside a box have to be added up and calculated to see if the box has enough volume to safely accommodate everything. Wires that pass through and are shorter than twice the longest dimension of the box don't have to be counted.

And it's #12, right? #10 requires more space.

If you're going to keep that wiring in the box and add the #10 passing through, you definitely need to change the box to be a deep 1900 or an 11b.

IDK, but that got you a bondable ground wire, didn't it? Maybe that was why.

 

Yes it did..


Yes it is..

Can I remove the inside box completely and just run the romex through the nipple? #12 for the shed and the new #10?

If not what is an 11 lb box? I assume I cant use the single gang box I have there now? I need a double? Even though the only change will be # 10 passing through?

Raco 2-Gang 30.3 cu. in. Square Box-8232 at The Home Depot

Thats metal. Do they Make a PVC one?

 

An 11b is a 4 11/16 x 4 11/16". Your link is a 4"x4". Either would work and both are available at HD. They make very few plastic boxes with KOs in them. I would stick to a metal box.

You could just skip the box and run the two NM cables to the panel, but if it was me, I would keep the J-box on the inside. J-boxes are nice to have around for later use, like what you are doing now. If you do just run Romex through the nipple make sure to install a bushing on the end of the nipple.

 

I'm going to disagree with Tolyn on this one. To me, doing that creates an open chase into the outside breaker box, and you no longer have a complete enclosure.

If I were inspecting this (no danger), I would insist on a box with a cover on the inside end of that nipple.

Not a double or a 2-gang. HD mislabeled that box. It's a 4x4, or 1900, which is one option. The other is an 11B box. Here are some at Steiner, and here's one at HD. I have No Idea why HD keeps sticking "2-gang" in their descriptions of boxes that aren't!

Here are a couple of 2-gang, or 2 device, boxes at HD. They have a mounting bracket which you don't need. But that's OK, because you don't need this box anyway.

 

Im sorry. I am not understanding.

What is wrong with the single box I have now? Code wise?




And if I cant use that what exactly do I need? Code wise>

I show a 4x4 in that one link. Why was an 11lb suggested then? Why not just say a double size box?

 

It isn't big enough.

A 4x4 or an 11B.

11B boxes have lots of room so they're nice and easy to work in.

Never heard of one. What is that?

 

LOL... To the plumber any box that looks like it can hold one light switch is a single box. One that could hold two is a double size box...


I realize that some boxed have the screw holes for said switches or outlets and some dont...

So this is OK? Depth is pretty standard I assume?


Next item:......

OK with that said, after I run the #10 to the other side of the shed I will drill a hole, and

1. Do I need another box inside over there? Single size?
2. Then outside I assume a weaterproof type?

Shop CARLON Old Work Plastic Electrical Box at Lowes.com


3. Then if I bury run conduit under ground 18" with an ell on the end. Then run underground cable. ( Do same for camper side)
4. or, Run conduit with THWN along the RR ties. Is code sch 40 or 80?

 

Also this is going on camper side attached to a 4x4 post in the ground.. Anything to know here?

Shop Eaton 30-Amp Overhead or Underground Temporary Power Panel at Lowes.com

 

I've installed the 50A ones of these and they install easily.

 

On the other end of the shed, you could just run the Romex into the back of a box that you posted (although I suggest one with 3/4" hubs, If you can't find one get a metal weather proof box with 3/4" hubs), or do a box on the inside, nipple through the wall, and an PVC LB on the outside and do your splicing on the inside of the shed. Obviously, I suggest running 3/4" conduit to your RV box. I also suggest using stranded THWN wire in the PVC for ease of pulling.

If you run cable it needs to be down 24". PVC conduit you can go 18"

Sch 40 should fine as long as it is not subject to physical damage. If this is a driveway is some place that might get hit by a weed wacker, snow blower, or mower, I would go sch 80 then.

Your RV box should be pretty straight forward.

 

No way then with the burial cable then.....

OK last question...


Can I actually run electrical conduit along the ground on those RR ties by code?

 

Mike!

There is potential for a serious "overall" design flaw in this plan!

An RV in your driveway?
Who will help us with our plumbing disasters while you are out enjoying the open road?

Is there internet access in that RV?

 

Yes. PVC, EMT, IMC and Rigid conduit is all approved to be run exposed outdoor with approved fittings. Heck, you can run sealtight if you want, but that would look like hell and would be very expensive!

 

Only when its in the driveway... The few camp sites I been had nothing... Just wilderness and woods. Just how I like it.. Although my older kids hate it..LOL..


OK I decided I will do the metal conduit bury,, I will pick ax along the railroad ties. I will try to get at least 12". Although I roto till the garden I stay away from the RR ties as I have my irrigation there.




Can you tell me what to use?

I saw this, but metal stuff is way cheaper. I assume I need to water tight the metal stuff somehow?

Shop Southwire 1/2-in Metal Liquid Tight 50-ft Conduit at Lowes.com

 

If you plan to bury it you can not use EMT. The other three options (PVC, IMC, RMC) are still an option. Conduit in the ground is more "water resistant" than "water proof". This is why we always mention that the wire has to have the "W" rating in THWN. The pipe will get some water in it with condensation.

Your last link is Sealtight (trade name) I mentioned. You could use that but only if it is marked for direct burial. I have never used it in that way so I do not know if it is or not. I would use IMC if available. Otherwise RMC is good too.

IMC and RMC is very similar to galvanized piping. (different pipe though) You only have to bury IMC and RMC 6" down but any deeper is fine too. It should be installed similar to other threaded piping installation I'm sure you have done before, just don't use any thread dope. You should be able to get 2 #10s (or 3 if you want to pull a ground, the steel pipe can be your ground) in 1/2" IMC or RMC. If you use steel I would recommend your boxes mentioned earlier to be steel.

 

Dont know what thats is.. Ill have to look online...

 

RMC is Rigid Metallic Conduit and it is almost (but not quite) the same as galvanized water pipe. IMC is Intermediate Metallic Conduit and it has the same outside dimension as RMC (and galvanized water pipe) but a much thinner wall. Both of the metal conduits are about five times the cost of schedule 40 PVC conduit or about $5-$8 a ten foot length in 1/2 or 3/4 in nominal size.

 

No buried conduit will remain watertight. That's why THWN conductors have to be used in it.

Buried metal conduit needs to be either rigid metal conduit (RMC) or intermediate metal conduit (IMC). RMC is the one I use because it gets threaded with standard threading heads. IMC requires special ones.

Mike, here's a thought -- is that your fence? If so, what would you think of running the conduit on it? I'm thinking you could trench from the corner of the shed across your garden, pop up next to the fence, come up 3 or 4 feet, set a box, and run along the center cross-piece to your driveway. Then you could mount a NEMA 3R box with your RV receptacle in it and be done. Or you could go back underground to get to wherever you'd like to plug in.

Yeah, no Joke? They think a lot of that stuff. As Tolyn just said, Hot tip: only buy that stuff at a supply house.

Besides that, IDK if that stuff is rated for burial. You'd have to check that out. As far as I can tell, Southwire's Titan line isn't. It's really designed to be used where you need a flexible conduit in a wet environment, above ground. Feeding the condensing unit for a central A/C system is one popular use.

BTW, I wouldn't consider running this in anything less than 3/4", as Tolyn said earlier. You can buy Southwire's Ultratite conduit, 3/4", at Lowe's for "only" about $35 for 50'. And then you have to pull a ground (you don't in Titan, but the connectors are more expensive for that too).

Unless you use metal all the way. Then you would only have to pull one hot and one neutral. Using stranded wire, that should be fairly easy to do in 1/2" pipe.

TMI?

Which way are you leaning now? What would you like some clarification on? Anything?

 

My head is spinning...


Why 3/4? Why not 1/2 "?

This liquid tight stuff says for direct burial on the box. Is that in the code and is it allowed in NJ? I can bury this 6"???

Shop Southwire 3/4-in Liquid Tight 50-ft Conduit at Lowes.com

or this

Shop Southwire 1/2-in Metal Liquid Tight 50-ft Conduit at Lowes.com

And if this is the rigid threaded stuff... forget it... Its not any cheaper. Plus it will be like doing plumbing and I dont want that. I am trying to pretend I am an electrician here!!!!

Geez why does that direct bury cable have to go so deep for... uggg...


The fence may not stay is why I am not running it there. Plus that may look more hokey!!!

Since the liquid tight is flexable I will only need these at each end..

Shop Southwire 3/4-in Liquid Tight Connector at Lowes.com

 

Ah, so the Titan conduit is OK for direct burial.

All codes are local. Ask your inspector.Doubtful, but again, ask your inspector.

Yep, one connector on each end.

One day one of our other foremen and i and a green helper were trenching a supply in. I don't remember for sure, but I think about 250' x 3' deep x 2' wide. something like that.

The helper didn't seem too happy. The other foreman asked him what was up.

He said that he wanted to know when we'd get to the "real" electrical work. The other foreman replied "Son, it doesn't get any more real than this."

The helper didn't come back the next day.