Scared of electricity!!!

[Miriam C.]

Ilya, I don't think anyone here is going for a degree in EE. I posted that just to give a basic detail of electrical words and pictures.

It gives the basic idea pretty well. Now if you know a better one that is just the basics please share.

[reiltear]

Miriam, great comments. "Basic" and "better" depend on how far does one want to go. I'm not an EE either, but when I took "EE101" in college I needed calculus. And when I see an ammeter I prefer it to be called that.

I did a fairly big search on the internet for a simple tutorial and couldn't find any that would be both simple and correct at the same time. For those who don't mind switching their carriers(or just spending a little time reading), I found something which may be useful. The math does not go beyond a square root:

http://www.allaboutcircuits.com

Read the first 3 chapters in Volume 1 and the first chapter in Volume 2. I like this link because the 3rd chaper talks about electrical safety, which is glossed over very often.

http://www.sea.siemens.com/step/default.html

Check out "basic electriciy" first. I like this one because the "courses" offered there are free, very clear and they have self-tests to check your own progress.

Hope this helps, Ilya

[Miriam C.]

The Siemen's site is great. Thanks! Still it doesn't give good illustrations for simple wiring a light bulb. However those coarses are pretty expensive if Mike's work teaches them.

Seems an exhaustive search is in order. Honestly I think this board has more and better information than most I have seen.

[alloffroad]

Iam actually doing the siemans course as a training unit at my work. It is informative if you can get passed the big words . I just finished the basics. It took me about 1.5 hours. I will check out the other one asap and before I start the trailer work. I have a couple friends that know electricity inside and out so I will be picking there brains as much as I can.
I wonder if somebody can sticky the links that reiltear posted for anybody else who might be interested in some good reading.
Between these and everybodies help on this forum I will get through this in one piece.

I don't like to cut corners. It just makes thing dull.

[brian_bp]

I clicked through a couple of sections of the Siemens course. I wasn't planning to take any tests, but the questions come up at intervals so I just answered them. It all looked pretty good to me, as I would expect from Siemens. For a more thorough opinion, I would need to take the time to go through the rest, which I might some time, because it looks like good material.

[BPFox]

When it comes to electricity the best advise anyone can give is to keep it simple. For the novice one of the big problems is misused electrical terms. It can cause confusion and that's when mistakes happen. Here's an example of some of the terms I mean:

Ground. We often refer to a "ground" on our 12 VDC systems. In reality, Direct Current does not have a ground. If you choose to use the frame as a "Negative Ground" what you are really doing is using the frame as a conductor from your device to the negative terminal on the battery. In reality, "grounding" to the frame is unnecessary and will cause more electrical problems than anything else. How often have people with electrical problems been told to "check the ground" first. How often have you read that the number one electical problem is a "poor ground". It happens all of the time. Well here's a novel idea. If the ground is the number one problem, stop doing it! Problem solved. Keep in mind that the negative conductor is just as important as the positive conductor in any direct current system. If you run wires for both positive and negative you will eliminate 99.9% of your problems. Please don't confuse this with a Alternating Current ground where it becomes a issue of safety. No such "grounding" safety issues exist with Direct Current. If you look at the Zephyr Electric Schematic in an earlier post you will notice they have grounded the Alternating Current plugs to the frame. PLEASE don't do that. The frame is not a ground and will not offer grounding protection for your Alternating Current Circuits. What it will do is connect your AC and DC circuits together and that is not what you want to do.

How about this one; "Shore Power". I have looked at plenty of TDs and TTTs and have yet to see one that looks sea worthy to me. Now I am sure you could drive down to the local marina and plug in to the "shore power" there, but my guess most of us don't.

GFCI vs Circuit Breakers There are some folks that seem to think that these two devices provide the same service. They do not. Both are very important components in your Alternating Current systems. The Circuit Breaker is designed to protect your wiring from overload. The GFCI or Ground Fault Circuit Interrupter, protects you from electrocution. For Alternating Current to be safe you need to provide a safe path for the current to flow to mother earth. This is what the ground wire does. It gives a direct connection from your device to earth. Since none of us is driving an 8' ground rod into the ground every time we go camping we must rely on the ground that the camp ground we are using provides. A GFCI will insure that a good ground exists. If a good ground is not present, the GFCI will trip and shut down your AC plugs. This may seem like a pain, but it is there to protect you. A GFCI does not protect against circuit overload. You need a circuit breaker to perform that task. Just like a fuse on your DC dircuit, the circuit breaker protects your system from system overload. Since most of our wiring is hidden in the walls, we sure don't want them to over heat and start on fire. Protect yourself and your trailer by providing your own circuit breakers. Most outside power sources will have circuit breaker protection but since we travel to many sites with no guarantee of how those sites are wired, protect yourself with your own breaker and you know you are protected regardless of how the out side power source is set up.

Inverter vs Converter. Many times on this web site I have read about these devices as if they are separate systems. They are not. At the end of the day you will either have a Direct Current System or an Alternating Current System, or both. Inverters and Converters are just devices that are part of the above listed systems. They can be confusing since we are pretty much told to not combine our 12 volt dc and our 120 volt ac systems together and that's exactly what inverters and converters do. Keep in mind that these devices are just part of their respective systems. The "converter" is part of the Alternating Current system. It will keep your 12 volt battery from discharging and allow you to use your 12 volt dc system while connected to an outside 120 volt power source. The "inverter" on the other hand, is part of the Direct Current system and will allow you to use some of your ac devices when not hooked up to an outside power source. If you are not sure about how to include these devices in your system. Get some help. They are both handy devices and I highly recommend using them both in any trailer where both 12 vold dc and 120 volt ac are used.

Now I am not an electrical engineer, but I did study electrical engineering in college and I am currently a licenced electriction and I have to agree with reiltear on this one. Don't trust a site that doesn't get the terms right. The best advise I could ever give anyone is to keep it simple. Look at each system as a stand alone system. Take the time to learn and undertand how each system works. Go slow, think it through, ask for help and get someone who you trust and is qualified to check your work. Doing it right and doing it yourself can bring a great deal of satifaction when it all works the way it's supposed to. Good luck.

[brian_bp]

Inverter vs Converter. Many times on this web site I have read about these devices as if they are separate systems. They are not. At the end of the day you will either have a Direct Current System or an Alternating Current System, or both. Inverters and Converters are just devices that are part of the above listed systems. They can be confusing since we are pretty much told to not combine our 12 volt dc and our 120 volt ac systems together and that's exactly what inverters and converters do. Keep in mind that these devices are just part of their respective systems. The "converter" is part of the Alternating Current system. It will keep your 12 volt battery from discharging and allow you to use your 12 volt dc system while connected to an outside 120 volt power source. The "inverter" on the other hand, is part of the Direct Current system...

Good stuff, BPFox, but I would suggest one change:
The converter and inverter are bridges between the AC and DC worlds. Each of them has both AC and DC parts, so neither can be considered strictly part of one system or the other. The above description places them according to the system which supplies their input power, but they're each also part of the system to which they supply their output power. A battery charger (which is not quite the same thing as a converter, although the two functions can be combined) is another AC-to-DC bridging device.

All three functions...

- converting 120V AC power to 12V DC to run 12V appliances
- charging the DC battery with power from the AC system
- inverting 12V DC power to produce 120V AC power

are available in a single box, a setup commonly used on larger RVs.

[BPFox]

Correct you are Brian. I just didn't want to over complicate the discussion. In my particular case, my inverters will only be connected to the 12v dc system. There will be no connection to the 120 v wiring. When on 12v dc power only, any ac device I wish to use will need to be unplugged from the ac outlet and plugged directly into the inverter. This is electrically more efficient and I don't need to wire in a selection switch. The all in one system is pretty good, but would prove to be a budget buster for most builders on this board. Besides, it kind of takes the individual creativity out of it and where's the fun in that. Peace.

[alloffroad]

I don't have much knowledge or use of inverters. I know I can run a small tv, lights, etc with the cheaper type of inverters with out much worry of draining the batteries. But what about items like a cooking hot plate or, hypatheticly , a hair dryer. These items would almost certainly not be used camping but what if.
I plan on building a battery box big enough for 4 deep cell batteries. For a 4 day outing would this be good enough or a serious over kill. Maybe 2 would be sufficiant running normal stuff like vent fans and maybe a 12 volt heater. I have a solar powered battery charger to help during daylight hours.
I am likeing the idea of just running wires for 12 volt power and using inverters when and where needed. I can hook up car stereos. This probably isn't much different. Power from batt. to an inline fuse to a fused distribution block then to outlets. What guage wire should be used and spacificly what kind. When I go to home depot what am I going to purchace. i.e. romex?

[pete.wilson]

Hey

I use a 2200 watt inverter for my AC needs and I use two series 31 trolling motor batteries that I bought at Cabelas(6awg wires from batts to inverter). Fully charged they will run my microwave oven, fan and a few other things for 2 days with no problem. A electric ceramic heater keeps thing warm but does draw some juice. My batteries are connected in parrallel, then there is a large fuse in-line on the red lead. Ground is ground, batteries to the inverter. My cord from the inverter outlet to the wall outlet boxes is from a 14 gauge 3 wire 100ft extension cord, I used it because its supple and for short runs works fine w/o heating issues. I used standard house blue electrical boxes. White wire is hot to the shiny nickel screw on the outlets, black is neutral and goes to the brass screw on the outlets and green is ground and goes to the outlet gnd. lug. Note: If using a ceramic heater or other appliance over 1500 watts, then I would go to a 12awg cord/wiring. My inverter has built in circuit breakers if needed. I fused the 12v red lead but you could use a circuit breaker also. Also useful is a battery isolator switch which allows you batt 1, batt 2 or none. I also have a 2amp trickle charge built in to charge things when the batteries are tucked away and easy access isn't needed. A small 12v digital voltmeter that plugs into a 12v oulet (walmart has then in automotive for about $15) is handy for keeping track of your batts. condition while your camping.

Keep in mind if your going to have four batteries; make sure your weight is distributed equally, ie. two batts left of center, 2 batts righ of center, same distance front to back in your setup.

Pete Wilson

[bobhenry]

Hey

I use a 2200 watt inverter for my AC needs and I use two series 31 trolling motor batteries that I bought at Cabelas(6awg wires from batts to inverter). Fully charged they will run my microwave oven, fan and a few other things for 2 days with no problem. A electric ceramic heater keeps thing warm but does draw some juice. My batteries are connected in parrallel, then there is a large fuse in-line on the red lead. Ground is ground, batteries to the inverter. My cord from the inverter outlet to the wall outlet boxes is from a 14 gauge 3 wire 100ft extension cord, I used it because its supple and for short runs works fine w/o heating issues. I used standard house blue electrical boxes. White wire is hot to the shiny nickel screw on the outlets, black is neutral and goes to the brass screw on the outlets and green is ground and goes to the outlet gnd. lug. Note: If using a ceramic heater or other appliance over 1500 watts, then I would go to a 12awg cord/wiring. My inverter has built in circuit breakers if needed. I fused the 12v red lead but you could use a circuit breaker also. Also useful is a battery isolator switch which allows you batt 1, batt 2 or none. I also have a 2amp trickle charge built in to charge things when the batteries are tucked away and easy access isn't needed. A small 12v digital voltmeter that plugs into a 12v oulet (walmart has then in automotive for about $15) is handy for keeping track of your batts. condition while your camping.

Keep in mind if your going to have four batteries; make sure your weight is distributed equally, ie. two batts left of center, 2 batts righ of center, same distance front to back in your setup.

Pete Wilson

Before we lead someone astray, while you have your system wired correctly (white to silver) (black to gold ) the white wire is neutral and the black is hot.

[pete.wilson]

Hey

BobHenry,

My Bad! Your absolutely correct, I had it backwards. White is neutral and Black is hot.

Pete Wilson

P.S. Everyone should buy one of those handy little AC outlet testers that will tell you if they are connected backwards before you plug anything in, they are handy.