I am putting a concrete pad in my back yard where I can park my trailer, and also put up a shed for storing my lawnmower and garden tools.
I would like to mount on a 4x4 post a 30A outlet for the trailer and also a 15A GFCI outlet on the same post. Also I would like to run a 15A line from the post to the shed for a light and outlet there.
I know I can run a 30A line from my breaker box to the pad using 10 ga. wire (in conduit of course). Is there such a thing as a small breaker box that could be mounted on the post where I could put a 15A breaker, or do I need to run two separate lines from the house?
I think I have seen breaker boxes like this in campgrounds and other places, but I’m not even sure what to ask for. Would Home Depot carry something like this, or would it have to be special ordered (if it exists).
Not sure if that would do what I want. What I need is something that I can tap into my 30A circuit and install a 15A breaker so I can run some extra outlets and a light for the shed.
ETA: On looking at Home Depot’s web site, maybe something like this would do what I need.
From the breaker box to the pad is probably around 50 feet. Would I be better off to put a 50A breaker in the box and run #8 wire, then put a 30A and a 15A breaker in the outdoor box?
If you want to make sure you’re not overloading the 15A outlets or something, you can just get some weatherproof inline fuses at 15A at the splice point. Of course, you’d still be limited to 30A total load (well, 24A since the breaker can trip at 80% load) unless you run separate lines. (Or, as you noted, run a larger line out there and then basically do a small NEMA-3R load center or something, but that’s probably going to be more expensive than the extra conduit and wire out of your current panel).
The 30A outlet is at 120V. The trailer has a 30A plug, but unless I turn on the Air Conditioner, the only thing running is the DC converter/battery charger and the 12V lights. It has a 30A/15A adapter plug furnished, so the trailer can run on 15A, but with the A/C that’s a little bit of an overload.
So, in essence I would want a 30A outlet for the trailer, and 2 15A outlets that would be rarely used, plus a light bulb in the shed. I doubt I would ever overload anything with this setup.
That’s what I’d do, I might even go #6 if I thought there was at all a chance I’d want more power in the area. You need a disconnect in the shed anyway, so would it make sense to run the main cable there, put in a standard subpanel, and run a #10 and a #12 out from the shed to the pole?
You can also run two circuits in the same conduit and just upsize the conductors (they’ll be derated due to more than 3 current carrying conductors), but that’ll be the easiest solution.
Agreed. Doing it 100% right also gives you the satisfaction that when you are sitting in your chair watching the History Channel late at night tossing back a cold one, you don’t have to worry if your shortcut that saved you $40 is setting fire to your outbuilding right now. Two rules for life: Don’t ever mess with angry women or electricity. They can both put you in an early grave.
if the wire distance is over 50 feet then you would want a ground rod at the shed. then don’t run a grounding wire from the house. use a subpanel suitable as a service panel. subpanel in the shed keeps it out of the weather.
This is pretty simple to do. You don’t need two wires, you can do it with one wire, just buy some 10 / 3 wire which is 3 wires in the romex plus a ground wire instead of two. Buy a double breaker, (normally used for a 220 circuit) one wire to each side of the breaker (black and red wires) and the neutral (white) to the ground bus as you would normally do. You can use one neutral as a common return.
This is done a lot to save wire, usually done to a kitchen under a sink to power both the dishwasher and the disposal.
You split the wires up at the outlets, but you need to drop the wire size down to a #12 for a 20 Amp; 14 for a 15 Amp to fit under the terminal lugs on the small outlet. Adding the GFCI is not a problem but you would be best off to put two GFCI breakers back at your panel instead of one 220 in the same position, then the whole thing would be GFCI protected ( as all outdoor outlets should be ).
By the way a 50 foot length is nothing. Therewould be no measurable voltage drop in only a 50 foot run.
Do NOT add another ground rod. DO NOT DO NOT! DO NOT!
This is a good way to get killed, seriously. Don’t have time here to go into the explanation, but trust me, this is an EXTREMELY DANGEROUS THING TO DO !!!
OK?
This sounds like a really bad idea. The “neutral as a common return” could be carrying twice the current that the breaker is designed for, so 60 amps for a 30 amp double breaker. Also, the 15 amp outlets are “protected” by a 30 amp breaker.
The currents would be 180 deg out of phase with each other and would tend to cancel each other out (assuming you have a typical split phase service and not 2 phases out of 3 phase as is sometimes done). At full current they would sum to 0, not 60. Worst case you still have 30 amps on the neutral.
The 15 amp outlet on a 30 amp breaker is definitely a big no-no though.
I like this idea the best out of everything in this thread, along with the GFCI that was mentioned in another post.
I was an electrician and instrumentation technician in power generating plants for twenty five years. Trust me I know what I am talking about.
First you can always put a smaller device; outlet, light fixture, motor, etc. ; on a larger wire as long as the physical connections are done correctly. What is meant bythis is that the terminals on a 15 amp outlet will not accommodate a wire larger than a # 12, they won’t fit. Actually a 15 amp receptacle requires only a#14 wire. You can always put a smaller device on larger wire, as nothing that draws more than 15 amps can be plugged in to a 15 Amp receptacle. The opposite is what is bad, and causes fires. If you were to use a #14 wire in a circuit, and connect it to a 30 amp receptacle, then plug in a device that drew more than 15 amps, the wire would begin to heat up, and will eventually burn. The opposite is not true.
And as to the “engineer” who was speaking of the two circuits being “Out of phase” with each other, all I can say is this. Utility power to a home is SINGLE PHASE. Commercial buildings, factories, etc use three phase power, usually at 480 Volts.
All of the circuits in a home are on the same phase, if they were not, your stove, dryer, and AC system would not operate, or be damaged, as they are all 220 circuits.
I am afraid you guys just do not know what you are talking about. My advice; hire an electrician before you kill yourself.
There are two types of residential electrical service. The first type, which is by far the most common, is that you have a single split phase transformer. This means that you take a single center tapped transformer and ground the neutral. This grounded neutral becomes your zero reference. Because it’s a center tapped transformer, you get 120 volts from either line to neutral and 240 volts from line to line.
Less common, but still in use in some places (some parts of New York City, for example, and a few other places across the U.S.) instead of a single split phase, you get two legs of a 3 phase system. In this case, your line to neutral voltage is still 120 volts, but your line to line voltage is only 208 volts. Most 240 volt appliances you buy in the U.S. are capable of operating at either 208 or 240 volts, though it will take longer for your oven to heat up to temperature (if it’s an electric oven) and your clothes will take longer to dry, for example. In this type of system, the two lines are 120 degrees out of phase with each other.
Now, ignoring that second type of service for the moment, let’s get back to the single split phase. I’m not sure why you are having trouble understanding that a single split phase has two lines which are 180 degrees out of phase with each other. The voltage, relative to the center tap, ranges from 0 at the start of the sine wave, to +170 and -170 at the peak of the cycle, then back to 0 then to -170 and +170 (the negative swing of the sine wave), back to 0, then repeats. As the first line goes up positive in voltage the second line goes down, and vice-versa. In other words, the voltages are 180 degrees out of phase with each other.
At peak, assuming a current of 30 amps rms, you are going to have about +42 amps on line one and -42 amps on line two. Now the way I was taught math, +42 and -42 added together makes zero. Similarly, during the second half of the sine wave, you’ll get -42 amps on line one and +42 amps on line two (again, 180 degrees out of phase with each other) which again add to zero. Of course this also assumes no reactance on the line, but that’s a different topic.
Or maybe I just don’t know what I’m talking about, and we should just trust you instead.
Your stove, dryer, and air conditioning system all work precisely because the two lines are 180 deg out of phase.; If you chose two lines in your house that were in phase, the difference between them would be 0 volts not 240.
I guess you just don’t get the concept. I would try to teach you, but…
A teacher can only teach if the student is willing to learn.
