bronco638
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Post by bronco638 on Oct 4, 2013 6:56:58 GMT -8
Hi All, First, let me state that as a noob to this board (but not a noob to forums in general), I'm going thru and reading all of the posts in this sub-forum. Most make sense, some do not. I have a basic grasp of electricity and how it works but am also smart enough to know that I'm not an expert. If I have to hire a pro, I have no issue with that. That said, I do like to be knowledgeable so that I can explain the set-up and/or diagnose issues. I am not asking for anyone to tell me how to do this. I would just like ti understand what I need and how it works. My wife and I recently bought a 1962 Broken Arrow Tepee (some of you may have seen my "intro" post). My wife and I would like to re-configure the galley (it is currently dis-assembled). At the same time, I would like to address the electrical system so it is capable of handling the load. The current wiring configuration is (I believe) pretty much original. On the outside of the trailer, I have a weather-proof cap that covers the typical extension cord type male connector (two flat prongs, one tubular prong - ground). Inside the trailer, I have the original "fuse box" with 30 amp screw-in fuse (sorry for out-of-focus): The trailer currently has three lights and two receptacles. The lights are in the rear, one on each side and curb-side in the front. The receptacles are in the galley and front street-side where a light fixture used to be (in other words the trailer used to have four light fixtures, one in each 'corner' with a receptacle in the galley). The previous owner had a small a/c unit and a small (dorm room sized) fridge plugged into a power strip. The power strip's male connector dropped thru the floor to be connected to shore power (separately from the trailer's shore power connection). The p.o. also ran a small extension cord from the power strip for his wife's computer. Here's what we would like to be able to do: - Return the front street-side receptacle to a light fixture
- Add a receptacle to the dinette (to power a laptop)
- Add a receptacle to the galley in the upper cabinet (to power a small LED TV, for viewing from bed)
- Add a receptacle to the closet (opposite the galley) to charge phones/iPad/Kindle/etc.
- Provide power to the A/C unit
- Provide power to two mini-fridges (AC/DC)
I know that I'll need to check for power consumption figures on the A/C unit and mini-fridges. My wife would also like to be able to run a small microwave and/or coffee maker from the galley receptacle (not at the same time). What throws a wrench into all of this, from my perspective, is that Kasey would like to be able to run one (or both) fridge on DC power while we're towing (so we don't need a cooler or have to wait for the fridge to cool down upon arrival). I think I need: - A 30 amp panel with two 15 amp breakers
- An AC to DC converter
- A deep cycle battery
I read thru kto's post (the one that's locked) and am a little confused by the change to, what appears to be, a 220vac plug on the outside of the trailer (is that for 50 amp service?). Based on what I know, I think the first list is too much for the second list to support. Can anyone tell me if I'm even in the ballpark? TIA, Dave.
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txoil
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Post by txoil on Oct 4, 2013 7:30:49 GMT -8
Dave.. I just finished wiring on our 60' Deluxe and the power requirements you listed are very close to what our camper now has installed. As we found it, there were three ceiling lights with a receptacle and a small lamp in th eback corner by the gaucho. There was no fuse or breaker but the wires were just spliced together and an extension cord hung out of a hole on the curb side. (real safe, wasn't it?) I pulled all the old wiring , and installed a six slot breaker box rated for 100 amps, with a 30 amp main breaker and four circuits of 20 amps each. We now have four dual receptacles and the three singles in the light fixtures (11 individual sockets). The power load consists of a dorm fridge, portable A/C unit, 29' flat panel TV, 60 psi water pump and six light fixtures. Adding amperage for all that we are using will yield 13-14 amps, with everything on simultaneously. Knowing this, I installed 20 amp breakers. I used 10/3 Romex wire for the main breaker and 12/3 Romex for the others. The PO had included a 30 amp Marinco sealed shore plug so I installed that, and acquired both a 30 amp cord for a standard RV power box and a 30/15 amp adapter to use a standard extension cord when there is not 30 amp service. After going round and round I decided to not bother with a 12v battery/recharge system, and I installed a pair of battery powered LED ceiling lights with remotes for use when no power is available or the generator is off. This has worked out really well for us so far. Let me know if I can offer assisstance in any way!
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bronco638
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Post by bronco638 on Oct 4, 2013 9:57:47 GMT -8
Thanks tx, it does sound as if our installs are similar. There is one difference, I do not plan to replace any wiring as the trailer is not being refurbished/restored. I have to assume that the existing wiring is sound and is 12/3 (to work with 30 amp service).
I've been trading emails with Mobiltec and he's of the opinion that the little AC/DC fridges don't perform that well. I'll have to determine how good they are since this is something that my wife really would like to have.
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cowcharge
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Post by cowcharge on Oct 4, 2013 14:31:35 GMT -8
If the fridges aren't compressor fridges you will probably be disappointed. Those thermo-electric coolers they make for truckers are only about a quarter as efficient as a compressor fridge, and can only drop the temp a certain amount below ambient temperature (one google hit said 54f below ambient, so on a 100-degree day it only gets down to 46), so the hotter it is outside, the warmer your cooler stays inside. They can't make ice or keep food frozen. 12v compressor fridges are very expensive, so the best bang-for-buck is probably to use a 110v fridge, powered by an inverter/battery combo when you're not plugged into shore power (and charged by the truck).
You could power a 12v fridge while towing with a simple battery isolator switch, which switches the output of your alternator to a second battery once the car battery is recharged. You would probably either have to add a resistor, or go through a battery, to get the right voltage to your fridge, as the alternator puts out more than 12v (I'm a little out of my depth with resistor values, college physics was too long ago). Or do the same with a 110v fridge, using an inverter.
As for your load, it would take 27.5 60-watt Edison light bulbs to blow a 15-amp breaker (15A x 110v = 1650 watts: 1650 watts / by 60 watts/bulb = 27.5 light bulbs), so don't worry about lights. Put a disco ball in there if you want. CFLs (yuk) take about 15 watts, LEDs a lot less than that.
It would take any combination of 1650 watts at a time on one circuit to blow a 15-amp breaker (1650 watts = 110v x 15a). Common microwave wattages I have seen are 800 and 1500. The 1500 could possibly trip a breaker when it starts, due to the high starting amp loads that many appliances have. Ditto on appliances with motors and heating elements, like hair dryers and AC units. My old, old 800-watt microwave that came with the camper struggles mightily to pop corn running off an 800-watt generator (looks like it's in a brownout, but it pops the corn eventually).
Just looked on the bottom of our old Gevalia coffee maker, it said 900 watts, which would be 8.18 amps (900w / 110v = 8.18 a). So it would take more than half of one circuit by itself.
An LG 5000-BTU window AC at Home Depot says it only draws 4.8a, so you could run it, the coffee maker (8.18) and sneak in two or three light bulbs at once, and be just under 15 amps (dunno at what amperage a 15-amp breaker actually trips).
Water pump probably won't draw many amps just drawing from a tank.
Modern TV, no problem. My new 24" Vizio only draws 95 watts, which is only .86 amps. Watching a DVD on my laptop (but not charging) using my TV for a monitor was only drawing an amp or two from my batteries, which means it was only drawing an amp or two divided by 9 in amps AC (It takes about 9 amps DC to make 1 amp AC through an inverter).
Laptop, no prob except during charging. Running my laptop plugged into my inverter and then into my TV barely made the fan come on in the inverter. Until I plugged it in after using it on battery. Then my inverter fans were running loud, although I didn't put a meter on it.
Phone chargers use nothing. The kindle and ipad might use more charging power than a phone, but probably not as much as the laptop. The labels will say, but an ammeter's more accurate because it measures the actual total, including wire losses and other inefficiencies like in the inverter.
It's as simple as writing down the amps or watts (divide the watts by 110v to get the amps) on the data plates of all your appliances and adding them together in different combinations on your two circuits to see what you can run together without tripping a breaker. Maybe the AC and fridge will fit on one circuit and you can use the other one for lights and everything else.
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Post by bigbill on Oct 4, 2013 15:14:20 GMT -8
Cowcharge you do an excellent job of explaining amp load to people so that it is understandable.
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cowcharge
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Post by cowcharge on Oct 5, 2013 5:07:01 GMT -8
Thanks Bill! It took me a lot of research and half-remembered science to get it straight myself, might as well save folks the work.
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Post by vikx on Oct 5, 2013 22:13:10 GMT -8
Here's an example of circuits in a vintage trailer with a 30 amp system:
1. Original 15 amp circuit, 110 lights and maybe a outlet or two.
2. New 15 amp circuit, a few outlets plus operate a fridge or other appliance. 3. New 20 amp circuit, kitchen outlet for microwave/coffee maker, etc. Also outside outlet.
4. New 15 amp circuit for extras such as a small air conditioner. The A/C can be plugged in by itself, bypassing the trailer system.
Old Electrician's Rule of thumb: since all circuits, outlets, fixtures won't be used at the same time, total amperage should be less than twice the incoming amperage. 30 amp/10 ga wiring to breaker box = circuits totaling less than 60 amps. Above is 65, too much, hence bypassing the trailer system for the air conditioner
NOTES: Most small vintage trailers have a 15 amp inlet (or dangling cord) and 14/2 wire thru out. To upgrade to 30 amps, the wire from the 30 amp inlet to the breaker box MUST be 10/2 with ground. One of the few trailers rated at 20 amps (12/2 wiring) are the mid 60s Aladdins. Amazing quality; 35 amp inlet. If you use common sense, it is easy to keep the electrical system in bounds. One major thing at a time.
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bronco638
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Post by bronco638 on Oct 7, 2013 7:38:09 GMT -8
Cowcharge you do an excellent job of explaining amp load to people so that it is understandable. +1. Thanks everyone for the responses. I need to gather some electrical data on the appliances I plan to uses, in the trailer. Then, I can move forward. IIRC, I read someplace that "shore power", at most campgrounds, is usually 30 Amp Service. Is that correct, for the most part?
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txoil
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Post by txoil on Oct 7, 2013 10:30:18 GMT -8
That is correct. Most RV parks have a standard box with a 50 amp 220V outlet, a 30 amp outlet and a couple of 125V 15 amp outlets. You might want to pick up a 30 amp to 15 amp adapter (only a few dollars at any Walmart or home inprovements store) in case your park does not have boxes with 125V outlets. It DOES happen.
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Post by kto17 on Oct 8, 2013 9:19:27 GMT -8
That is correct. Most RV parks have a standard box with a 50 amp 220V outlet, a 30 amp outlet and a couple of 125V 15 amp outlets. You might want to pick up a 30 amp to 15 amp adapter (only a few dollars at any Walmart or home inprovements store) in case your park does not have boxes with 125V outlets. It DOES happen. I thought I would mention, I have come a cross a few campgrounds recently that did not have 50 amp power. All had 30 amp and some had 20amp GFCIs. When you pick up that adapter at Walmart also get a 20 male to 30 female so you can plug in at home to run a small heater or small AC unit if you don't want to winterize too early or want to cool it down in the summer. ALSO a big plus is to run your fridge the day or two before you leave to get it cold and put food in it. It will stay cold on the road like a cooler for a few hours. Just strap the door shut. Those latches don't always hold... ask my wife You can also get a 50 amp to 30 amp adapter just incase and they are at Walmart also.
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Post by kto17 on Oct 8, 2013 9:27:01 GMT -8
- Return the front street-side receptacle to a light fixture
- Add a receptacle to the dinette (to power a laptop)
- Add a receptacle to the galley in the upper cabinet (to power a small LED TV, for viewing from bed)
- Add a receptacle to the closet (opposite the galley) to charge phones/iPad/Kindle/etc.
- Provide power to the A/C unit
- Provide power to two mini-fridges (AC/DC)
I know that I'll need to check for power consumption figures on the A/C unit and mini-fridges. My wife would also like to be able to run a small microwave and/or coffee maker from the galley receptacle (not at the same time). What throws a wrench into all of this, from my perspective, is that Kasey would like to be able to run one (or both) fridge on DC power while we're towing (so we don't need a cooler or have to wait for the fridge to cool down upon arrival). I think I need: - A 30 amp panel with two 15 amp breakers
- An AC to DC converter
- A deep cycle battery
I read thru kto's post (the one that's locked) and am a little confused by the change to, what appears to be, a 220vac plug on the outside of the trailer (is that for 50 amp service?). Based on what I know, I think the first list is too much for the second list to support. Can anyone tell me if I'm even in the ballpark? TIA, Dave. Dave, your bring up a good point i neglected to mention. Don't confuse a 3-blade 30amp RV plug with a 3-blade Clothes Dryer plug. They are different. The 3-blade 30 amp RV plug is a 3 wire 110V plug with 10ga wires; Hot, Nuetral, and Ground, one of each. You need a connector also rated for 30 amps if you are upgrading to a 30 amp system. A 3-blade extension cord like you plug in your home is not rated for 30 amps.
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Post by kto17 on Oct 8, 2013 9:50:39 GMT -8
If the fridges aren't compressor fridges you will probably be disappointed. Those thermo-electric coolers they make for truckers are only about a quarter as efficient as a compressor fridge, and can only drop the temp a certain amount below ambient temperature (one google hit said 54f below ambient, so on a 100-degree day it only gets down to 46), so the hotter it is outside, the warmer your cooler stays inside. They can't make ice or keep food frozen. 12v compressor fridges are very expensive, so the best bang-for-buck is probably to use a 110v fridge, powered by an inverter/battery combo when you're not plugged into shore power (and charged by the truck). You could power a 12v fridge while towing with a simple battery isolator switch, which switches the output of your alternator to a second battery once the car battery is recharged. You would probably either have to add a resistor, or go through a battery, to get the right voltage to your fridge, as the alternator puts out more than 12v (I'm a little out of my depth with resistor values, college physics was too long ago). Or do the same with a 110v fridge, using an inverter. As for your load, it would take 27.5 60-watt Edison light bulbs to blow a 15-amp breaker (15A x 110v = 1650 watts: 1650 watts / by 60 watts/bulb = 27.5 light bulbs), so don't worry about lights. Put a disco ball in there if you want. CFLs (yuk) take about 15 watts, LEDs a lot less than that. It would take any combination of 1650 watts at a time on one circuit to blow a 15-amp breaker (1650 watts = 110v x 15a). Common microwave wattages I have seen are 800 and 1500. The 1500 could possibly trip a breaker when it starts, due to the high starting amp loads that many appliances have. Ditto on appliances with motors and heating elements, like hair dryers and AC units. My old, old 800-watt microwave that came with the camper struggles mightily to pop corn running off an 800-watt generator (looks like it's in a brownout, but it pops the corn eventually). Just looked on the bottom of our old Gevalia coffee maker, it said 900 watts, which would be 8.18 amps (900w / 110v = 8.18 a). So it would take more than half of one circuit by itself. An LG 5000-BTU window AC at Home Depot says it only draws 4.8a, so you could run it, the coffee maker (8.18) and sneak in two or three light bulbs at once, and be just under 15 amps (dunno at what amperage a 15-amp breaker actually trips). Water pump probably won't draw many amps just drawing from a tank. Modern TV, no problem. My new 24" Vizio only draws 95 watts, which is only .86 amps. Watching a DVD on my laptop (but not charging) using my TV for a monitor was only drawing an amp or two from my batteries, which means it was only drawing an amp or two divided by 9 in amps AC (It takes about 9 amps DC to make 1 amp AC through an inverter). Laptop, no prob except during charging. Running my laptop plugged into my inverter and then into my TV barely made the fan come on in the inverter. Until I plugged it in after using it on battery. Then my inverter fans were running loud, although I didn't put a meter on it. Phone chargers use nothing. The kindle and ipad might use more charging power than a phone, but probably not as much as the laptop. The labels will say, but an ammeter's more accurate because it measures the actual total, including wire losses and other inefficiencies like in the inverter. It's as simple as writing down the amps or watts (divide the watts by 110v to get the amps) on the data plates of all your appliances and adding them together in different combinations on your two circuits to see what you can run together without tripping a breaker. Maybe the AC and fridge will fit on one circuit and you can use the other one for lights and everything else. Cowcharge makes some good points! One thing to look out for; Some appliances have the amperage on the side. See Cowcharges AC unit refernce above. It may be rated at 4.8 amps at 120 and not 110. Run the math, 4.8 amps x 120v = 576 watts then divide 576 watts /110v=5.2 amps. See how that difference can add up with 2 or three appliances... In reality the voltage at campgrounds vary slightly but you need a baseline to set your values for a total amperage. Its safer to assume 110v for your math and that gives you the higher amperage and possibly some cushion. I like to separate a curcuit like a dedicated circuit for my electric 1500 watt heater which is 13.6 amps @110v at full blast. Then I can if needed add a minmal draw item to that circuit that will never see full draw at the same time. LED lights would be an good example. I use the same circuit for my AC unit in the summer and just unplug the heater and store it out of the way. My other circuit has the 2-way gas/110v fridge, 110v to 12v converter, other outlets, and lights. I would suggest putting the toaster outside the camper on a table and using the 20 amp campground power for it on an extension cord. A used 2-way RV fridge can run around $300 or less and a new one around $700 or more, but it will eleminate a good bit of draw. I'm fairly certain mine draws 1.4 amps on 110v.
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bronco638
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Post by bronco638 on Oct 8, 2013 11:22:22 GMT -8
Given what I have, based on the picture posted, I'm going to guess it might not be a bad idea to remove everything and ensure I have 10/2 wire to handle 30 amp service.
Cow made a good point about hooking the A/C unit up directly to shore power and by-pass the in-trailer electrical system entirely. I'll never run the A/C while we're towing (or boondocking - if we even do that).
I will get a 30A > 15A adapter, a 50A > 30A adapter and a 20A male > 30A female adapter.
My wife will be happy to hear that a cooled down and full fridge will make a nice cooler for the trip to the campground. I suppose we can make good use of those re-freezable blue cooler blocks. I will be sure to rig up some sort of way to secure the door. =)
Thanks for confirming that 50 amp connectors are different from 30 amp. What I read in your (kto's) post now makes much more sense.
Can you buy 30 amp extension cords?
Doug, when you say "2-way RV fridge" do you mean propane/electric? And, why do they have such a low draw?
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txoil
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Post by txoil on Oct 8, 2013 11:52:51 GMT -8
Given what I have, based on the picture posted, I'm going to guess it might not be a bad idea to remove everything and ensure I have 10/2 wire to handle 30 amp service. Cow made a good point about hooking the A/C unit up directly to shore power and by-pass the in-trailer electrical system entirely. I'll never run the A/C while we're towing (or boondocking - if we even do that). I will get a 30A > 15A adapter, a 50A > 30A adapter and a 20A male > 30A female adapter. My wife will be happy to hear that a cooled down and full fridge will make a nice cooler for the trip to the campground. I suppose we can make good use of those re-freezable blue cooler blocks. I will be sure to rig up some sort of way to secure the door. =) Thanks for confirming that 50 amp connectors are different from 30 amp. What I read in your (kto's) post now makes much more sense. Can you buy 30 amp extension cords? I believe that 15 amp is the maximum for 'standard' extension cords. I made a 30 amp power cord with 10/2 wire and bought the correct ends (30A 125V Marinco twist-lock male on camper side/30A three prong male end for RV box side) If you have not yet bought a power inlet, I highly recommend looking at the Marinco boat/RV 30 amp type.
Doug, when you say "2-way RV fridge" do you mean propane/electric? And, why do they have such a low draw?
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bronco638
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Post by bronco638 on Oct 8, 2013 12:22:06 GMT -8
It's dawning on me now that I'm going to need to upgrade to a 30 amp power inlet. The one that's currently in the trailer must be 15 amp (even though it has a 30 amp screw-in fuse) based on the prong sizes and orientation. You can purchase, thru Walmart, a 10/3 gauge, 30 amp RV extension cord that's 30 feet long. It's $50.
There are quite a few Marinco dealers in the immediate vicinity. I'll be sure to check them out.
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