Has anyone seen an outdoor outlet that has a DC plug and an AC plug instead of 2 AC plugs? I was thinking that would be ideal to have on my boler since I have a battery charger that takes AC or DC input. That way I can use DC when off grid or AC when on grid. I'm trying to limit the number of penetrations through the walls (already adding another for solar panels).
Maybe a real electrician will pop in here, but when I was working with utility drops inside a factory the code (NEC) required physically separating AC lines from low voltage (less than 30V) lines.
Probably have to get a blank cover plate for the electrical box and install your own outlets. Snoop around a Marine/Boating store for pieces to make it work (and seal.)
Alex,
You get power FROM an outside source TO the camper through the plug on the camper. If you want to provide 12VDC FROM an outside DC power supply TO the camper's DC input battery charger you'd want a plug.
Your camper's shore power cord for 115 VAC is isolated from the camper's battery so that the battery doesn't power the exposed plug end of that cord. How would you keep the 12VDC battery from keeping the exposed plug end of that proposed DC plug from shorting?
As you reference "...instead of 2 AC plugs..." I'll presume you meant to say "instead of 2 AC socket outlets". In that belief you would be wanting one of the sockets to be a NEMA 5-15 for typical North American 115 VAC, and the other a socket of some configuration (see top line of this post) for powering some electrical consumer that would ordinarily be plugged into the car's lighter.
tractors 1:
re: the NEC rules as I understand them (not a licensed electrician by any means). The desire to keep the low voltage DC separate from the high voltage in an equipment enclosure has to do with the lock-out / tag-out requirements for service technician use. The low voltage is less likely to cause a shock and does not require being turned off prior to accessing the cabinet. This helps in diagnosing since the control systems are often low voltage powered. The high voltage / high current for drive motors and such are higher risk and require disconnection and locking to reduce risk. Keeping the high voltage and low voltage in separate cabinets means the lower voltage controls can remain powered while the muscles of the machine are in a safe(r), locked out state.
The mixing of 115 AC home outlets with built-in USB 5 VDC outlets (powered by that 115 volt AC supply) is common.
I wasn't clear in my first post. I would like to mount a weatherproof box in my trailer with outlet access from the outside. One outlet would be 12 volt coming from the battery and 12 volt system. The other outlet would be 110 volt AC that is hot when the trailer is plugged in. I tried searching for something like that and have been unsuccessful. I was hoping someone had found something that would work.
You can buy 115 VAC outlets that have a USB port to charge your phone, etc. However, they do not mix the 115 VAC system with anything like the 12 volt system! The USB port, which is 5 VDC, takes the 115 VAC and converts it to those 5VDC right there. No mixing of systems.
I guess it would take one more hole in the fiberglass shell to have a 12 VDC outlet on the outside...
Paul, I was hoping to find a way to have a single 110 AC plug and a single 12 volt plug in the same box but wired separately. I assume the 12 volt line would need to be shielded to prevent interference on the 110 line and vice versa. I did search to see if someone made outlets that would fit a standard AC faceplate but were 12 volts. At my house I have an outlet I bought that is modular and has 1 AC outlet, 1 RJ45 outlet and one TV/Cable outlet with a plate that covers all three. That's what got me to thinking about this.
First, I would just mount a round 120V AC outlet with cover, plenty of those on Amazon. For the 12V DC, I would mount one on my battery box, which is on the front of my trailer.
Be sure to get a female 120V outlet. Several of them are male plugs (bad idea).
I am an electrical guy, (Electrical Engineering Tech., working in instrumentation). It's true that by code AC and low voltage are required to be physically separated. You could use an access hatch that is larger than an electrical outlet, (like a shower hatch). One half could be dedicated to the AC and if you have a physical barrier the other side could be low voltage. This barrier would be behind the plate that the AC outlet mounts to. It doesn’t need to be anything fancy. A sheet of non-conductive plastic, mounted to some L brackets. All you need to do is prevent a loose wire from contacting the wrong side. If this is too large of a hole, you could use a snap in single outlet, but still physically separate it from the low voltage. https://www.homedepot.com/p/Leviton-...4-1W/301304781
I plan something similar. Though, on top of the 120 VAC and 12 VDC, I plan to include audio outputs from the car stereo and maybe an Ethernet plug. Probably other stuff too.
OK, I may have been wrong. It is not so much separation of voltages that matters. It is the separation of Class 1 and Class 2 circuits. Class 2 circuits are typically low voltage, current limited circuits, (thermostat).
In terms of instrumentation it is necessary to separate intrinsically safe, (power limited) and non-intrinsically safe circuits.
I can't find a rule that deals specifically with 12 VDC and 120 VAC.
This is not what you asked for, but does avoid an extra hole for 12v. I installed a watertight 12v outlet in the side of the top of my battery box. It is connected to the batter through an in line 20 amp fuse. The fuse holder is also watertight. It has worked for a couple of years with out trouble. I have consider using it for my solar input since my panels are movable.
I can't find a rule that deals specifically with 12 VDC and 120 VAC.
If anyone knows of such a rule, please advise.
Found it:
NEC Section 300.3(C)(1)
Section 300.3(C)(1)
(1) 600 Volts, Nominal, or Less
Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway.
FPN: See 725.55(A) for Class 2 and Class 3 circuit conductors
Yep Lynn, I will start looking at what I can fabricate. I'm thinking a bracket that fits inside a standard box that I can use to hold one standard format single AC outlet and modify one of those SAE ports to attach to the bracket I make. This will probably be an over the winter project after I pull and rebuild my other Jalousie window.
If you are going to fabricate something, you might look at PowerWerx for the 12V section. They make a number of 1 1/8" devices & panels that they fit. The closest 120V AC device I could find is a Marinco inlet (the opposite polarity of what you are looking for). It also needs a larger hole - 1 7/8". If you feel you could fabricate something using these two items, check with Marinco to see if they make a receptacle rather than an inlet in the same shell.
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