Post by kto17 on Jun 18, 2013 7:20:03 GMT -8
This is still in progress, sorry I have been very busy with life and starting to get active in the group again. I will be back with more and photos to finish it...... If you see something you think is incorrect feel free to pm me and I will look into it.
A few things before I start, disclaimer; I'm not an electrician and I'm not responsible for your actions. If you are not familiar with electrical wiring spend the money to have an electrician who knows RV wiring to inspect you trailer. You can check with local RV stores for qualified electricians on staff. I research what I don't know and make a plan and I wanted to share some of what I have learned. This is not a how-to but simply what I did and I'm sharing it. Do your own research and take 110V power very seriously. It is very dangerous and can cause serious even fatal injuries. It can also start a fire in your trailer. If you are not comfortable doing the work hire someone that is qualified to do electrical work and familiar with trailers. Just remember that you are trusting your life and possibly others to this system. This is not the time to be cheap and save a few bucks. Do it right. You'll sleep much better at night. Also, remeber these are vintage campers that have probably had multiple owners and you never know what the prior owner did that might be wrong. I don't care what they say about it working, you need to check the electrical system. Example mine had the 15amp plug on the outside, 35amps worth of breakers in the box, and the wire from the inlet to the box was original. See the silver braided insulated wire on the left, that's from the inlet. One of the prior owners didn't know what they were doing. Here is what it looked like. I have since clean up some of the mess. Did I mention someone had been taking their kids camping in it at the time I bought it. There is soo much wrong here I don't even want to think back on it. This is NOT how to do it. 
Info you might NOT know. Most of these vintage trailers came with a plug on the outside that looks like the end for an extension cord with a cover over it. If you only plan to run about 15amps of power that may be safe depending on its condition. If you plan to run 30amps that plug is not rated for it by todays standards. You could possibly even be turned down by a campground because of it. It is best to replace it with a new modern plug. I will talk about this later and show you what I did. Depending on the year your vintage trailer was made it could have old round glass fuses or more modern breakers. The glass fuses are not really bad but can be a hassle because you have to replace them if they blow, whereas a trip trips and can just be switched back on. You shouldn't just switch one back on unless you know why it tripped. You can replace the glass fuse box with a breaker box. You can find them at most Home Depot, Lowes, Ace Hardware type stores. Just like old houses, most of these old trailer don't have a ground wire. You can add a ground to your old system and I'll talk about that later also.
Wiring Sizing. It is very important that all wiring is the correct size. Too small a wire for the load (amps) and it heats up and can melt the insulator which can cause a fire. If you don't believe me feel a cord for a vaccuum or a space heater after its been on a while. It will be warm. Samll appliance manufacturers will use the smallest size wire they can to save money. Ok back on topic, You need to understand the sizing of wire called gauge (ga). The smalleer the number the thicker the wire and the more load it can carry safely. Example; 14ga wires can be used on a 15amp circuit but no more, but 12ga wires can be used on a 20amp circuit, and 10ga wires can be used on a 30 amp circuit. You will see on the outside of modern wiring a stamp that tells you what the wire gauge is and how many conductors, 14/2 means 14ga and 2 conductors (that does not include the ground wire so there are three strands). If you want to know more follow this link and make sure to look at the ** note at the bottom.
www.usawire-cable.com/pdfs/NEC%20AMPACITIES.pdf
I'm not going to get into voltage loss. Just know that the longer distance of power cord the thicker or bigger gauge (smaller number) the wire will need to be to carry the same amount of power. So if you want to be 100 feet from your generator, buy the 100 foot cable, yes it maybe more expensive than two 50 footers but it is probably a heavier gauge. If its not then do some research and make your own decision.
Evaluate your Needs, Make a Plan, and a Drawing. Ask yourself how much power you need. Make a list of everything that is either wired in or you would plug in and outlet. Check the amp rating on all electrical devices and add them up. it should be on a label on the side or bottom. If their is no rating, like on a light bulb, there is a simple formula.
watts/volts=amps Example; a 60watt lightbulb at 110V 60 watts/110 volts=0.55 amps (that is per 60 watt bulb)
Some devices will say ex. 1500watts at 120V. I always use 110 for my math because dividing by 120 will be less amps. I would rather error on the side of safe and you never know what voltage you are really getting at a campground.
You should also consider that some things like a fridge or AC unit have a higher start up amperage than they need to run. So if you round any numbers, round up not down. An electrical general rule of thumb is not to exceed 80% of your total amps on a circuit at one time. A circuit is the all the devices on one breaker or fuse. So if you decide that you are going to use an electric heater keep in mind a typical small space heater is 1500 watts. So that's 1500w/110v= 13.64amps. I would call it 13.7amps. On a 15amp circuit thats about all you can run, maybe a light or two, but then you risk triping the breaker and are exceeding the 80% rule. Tripping the breaker happens either when there is a surge, possibly from an AC unit starting up, or when there is too much load (too many amps) and hopefully never from a fault (bad wiring or outlet). Yes outlets can go bad, its not common but can happen.
Power Inlet (the plug on the outside of the trailer)
After you have made your list of all electrical devices and figured up your max load, then you can decide what inlet you need. 15amp, 30amp, or 50amp. If you choose 50amp be aware that not all campgrounds/parks have 50amp service or may only have it at certain sites. 30amp is the most common in modern campgrounds. Vintage trailer supply has many options to choose from but there are other sources.
Here is a 15amp
www.vintagetrailersupply.com/15A_Weatherproof_Inlet_p/vts-523.htm
I went with the 30amp stainless from VTS. I didn't want grey plastic visible.
www.vintagetrailersupply.com/Furrion_30A_Stainless_Inlet_p/vts-660.htm
Since I already had a 30amp 50 foot cord I bought the end adapter and watertight cover for this type of inlet. It was easy to install and didn't take long. I did have to make the hole slightly bigger through the aluminum and wood of the wall but my dremel made quick work of it. I do have some wiring experience. Again find someone qualified if you don't understand or are not comfortable doing the work.
www.vintagetrailersupply.com/Furrion_30A_F_Inlet_Plug_p/vts-674.htm
www.vintagetrailersupply.com/Furrion_30A_Inlet_Connection_Cover_p/vts-670.htm
Another Inlet Option. You can do away with the old inlet and hard wire a power cord. Vikx has been helping me and so some pictures are not mine. You'll see in the picture below, the power cord ( which are stranded wire) comes into a junction box and wire nuts connect it to a solid copper wire that then goes into the breaker box. This saves you money in the long run. You will need a place to run the hardwired power cord out of the trailer. They make a small pass thru thing for this. These are two newer boxes and a good example of a clean installation in a breaker box. Notice the ground busbar
Power Cords. Your power cord provides power but also safety. The power cord needs to be sized to match the rating of your inlet. This is because the different amp inlets have a different plug. They do make adapter plugs but do not exceed the rating of the adapter. Every 15amp to 30amp adaptor I have found is only rated for 15 amps. The power cord supplies your electrical system with its ground. This is why everyone should have a simple 3 light 15amp household plug tester and a 30 amp to 15 amp adapter if you are using a 30amp cord or the campground doesn't have the 20 outlets. Not to offend any electricians but everyone makes mistakes and some electricians helpers are not the brightest. You should always check the power outlet at a campground before pluging in. Just my opinion. FYI, I've never found a plug that was bad. Here is an example of one. I also carry a 30amp to 15amp adaptor to check the 30amp plug before plugging in. The two combined are about $10.
www.homedepot.com/p/Gardner-Bender-120-VAC-Outlet-Tester-1-clam-5-clams-master-GRT-3500/202867894
www.walmart.com/ip/Road-Power-15-30-Amp-RV-Power-Adapter/16817350
Wiring to the Breaker Box
This is where some poeple forget or get lazy. The same gauge rules apply here as everywhere else. If you have 30amp power you need the 10ga wire from the inlet into the box. Change this when you change the inlet, its much easier because 10ga dosen't like to bend much.
Breaker Boxes. You can buy a breaker box off the shelf at alomst any big box store. Again 30 amp is the most common, but you can do whatever fits your needs. In my picture above a PO used a black 30amp power cord and cut it up and used it for interior power wire, while the power rating is fine, there is one big issue. You don't want to use braided or stranded wire. Its too easy for a strand to be loose and contact another wire that it shouldn't. Solid copper wire is also much easier to secure. The breakers are sold seperate so make sure to buy the correct type and brand of breaker to match you box.
Ground Buse Bar. Many of these old trailers had no ground wired from the breaker box. You can and should add one for safety. Electricty follows the path of least resistance back to the ground and its better for it to be a wire than you or a loved one with their hand on the outside aluminum and barefooot standing by the camper. A ground buse can be found at the big box stores and a small one is probably about $5. You connect the ground coming in from the inlet to it and the grounds for all the circuts to it and secure the bar on the inside of the breaker box where there is room. You can barely see the ground bus bar in the bottom left of my box pictured above. It looks like a few screws side by side. One of the POs had installed it.
www.homedepot.com/p/Square-D-by-Schneider-Electric-4-Terminal-Ground-Bar-Kit-PK4GTACP/100207842
Inside Wiring and Outlets. Inside wiring and outlets fall under the same gauge wire for amps chart linked above. Below is a wiring diagram someone found in their Shasta 19 Deluxe showing the 110V and 6V ceiling light and battery. You should make a diagram or plan like this if you are completely redoing your electrical system not just for reference now but also later. Make your plan and revisit it a few times before starting because you are bound to make a few changes. 
