Starting my wiring project

[MontanaChinook]

I have a couple questions, hopefully not a ton of dumb ones.

I'm starting to more or less replace the wires in my Chinook, and at least all the connectors. So I have some very basic questions, just so I know I'm on the right track.

If, behind my converter, wires are going down through the floor of the camper, should I assume those wires are going to a ground? I'm guessing I should probably check the connection of those grounds to make sure they're good, but is that an ok assumption? Wires going down into the floor instead of into the converter are grounds?

When I wire things like the lights into the converter, in the most basic sense, I am connecting the positive wire to a wire coming out of the back of the converter (and adding a fuse to that place in the converter), and tying the negative into a ground, right? But I know I can share wires into a fuse in the converter, each electronic doesn't need its own location/fuse in the converter. ?

Second issue is my new furnace. I could just wire it the same as it was...but it's done a little screwy. This is why I need to make sure I know where the ground is. They spliced a lot of wires and shared a lot of + and - , which I'm sure makes sense, but it's confusing me since it's not as straightforward as it could be. I want to know, before I reconnect things, that I know why they are the way they are.

It's got a positive and negative, plus the two thermostat wires. No big deal. But it says in the instructions that if the furnace is going to be wired into a converter, that "the converter must be wired in parallel to the battery". What does this mean?

I have a more specific question...the way the old stuff was wired, the positive wire coming off the furnace connects to two wires. One going down through the floor, the other going into the converter. Then the negative wire also goes into a ground, but is also spliced with a wire going to the lights. I would guess the lights just tie into the same ground as the furnace, so that's fine and makes sense that those three wires would be spliced together. But why is the positive wire also spliced into what I would assume is a ground, since it's going down through the floor?

Sorry if that's a lot to visualize...

[WME]

Sounds like a rats nest.

Assume starts with , assuming things around electricty makes for sparks and some times flames

Follow the wires with your eyeball.

Clean grounds are not nice to have, they are required.

Does your rig have a fuse block? Some rigs have more than 1 block.

Most fuse blocks have a common + input to all the fuses and then indivdual + lines out to each load.

Parallel means that the + of the converter is connected to the + of the battery and the - to -.

The heater needs some eyeball work to see where the second + goes.

good luck and go slow

WME

[zero]

I have a couple questions, hopefully not a ton of dumb ones.

I'm starting to more or less replace the wires in my Chinook, and at least all the connectors. So I have some very basic questions, just so I know I'm on the right track.

If, behind my converter, wires are going down through the floor of the camper, should I assume those wires are going to a ground? I'm guessing I should probably check the connection of those grounds to make sure they're good, but is that an ok assumption? Wires going down into the floor instead of into the converter are grounds?

When I wire things like the lights into the converter, in the most basic sense, I am connecting the positive wire to a wire coming out of the back of the converter (and adding a fuse to that place in the converter), and tying the negative into a ground, right? But I know I can share wires into a fuse in the converter, each electronic doesn't need its own location/fuse in the converter. ?

Second issue is my new furnace. I could just wire it the same as it was...but it's done a little screwy. This is why I need to make sure I know where the ground is. They spliced a lot of wires and shared a lot of + and - , which I'm sure makes sense, but it's confusing me since it's not as straightforward as it could be. I want to know, before I reconnect things, that I know why they are the way they are.

It's got a positive and negative, plus the two thermostat wires. No big deal. But it says in the instructions that if the furnace is going to be wired into a converter, that "the converter must be wired in parallel to the battery". What does this mean?

I have a more specific question...the way the old stuff was wired, the positive wire coming off the furnace connects to two wires. One going down through the floor, the other going into the converter. Then the negative wire also goes into a ground, but is also spliced with a wire going to the lights. I would guess the lights just tie into the same ground as the furnace, so that's fine and makes sense that those three wires would be spliced together. But why is the positive wire also spliced into what I would assume is a ground, since it's going down through the floor?

Sorry if that's a lot to visualize...

I assume you are seeing the word "parallel" in the furnace instructions and not the instructions for the power converters. If so, they just mean the furnace gets wired so it can run off the converter, or off the battery directly. Technically, a true parallel hookup would mean the furnace gets hooked to the battery and converter all the time -but that is not the way it gets wired with certain converters.

Before you do anything . . you need to know exactly what model power-converter you have. Many 1977-1978 Chinooks (like mine) have a Basler PCM-15 or PC-25 "Lectro-Pak." The converters all get wired parallel with the house battery but that's only the way they get hard-wired. They don't work in parallel when actually being used since they have a "one way or the other" selector switch (if a Basler). If you have something else, I can't comment unless you post the make and model.

For example - the PCM-15 has a rocker two position rocker switch. One way attaches all the appliances wired to the converter - to the power supply and disconnects them from the battery; Push the rocker switch the other way and the same appliances run only off the battery and get no power from the converter.

High draw appliances are not supposed to be hooked to the converter -like the three-way refrigerator. Due to it's high amp draw it gets hooked directly to the battery. Radios and TVs are also supposed to be hooked directly to the battery but not because of amp-draw. More because of possible noise interference from the converter.

I can't imaging trying to wire any of it without knowing the make and model of the converter, with a wiring diagram. I have all the Basler diagrams here ( Lectra-Pak PCM15, PC25, PC35, PC50 and Central Power Pack ES-15).

General rules for your wiring are . . you need fuses or circuit breakers to match wire sizes. You also need DC switches and not AC switches unless they are dual-rated and "snap." On my 78 Chinook there were many chassis "ground" wires running through the floor and attached to the truck frame. Also many other wires passing back and forth through the floor - I guess to avoid many wire runs inside the living space. On mine, there were 6 places where wires came though the floor.

[MontanaChinook]

Ok, thank you. I will ignore the wires going through the floor and run my own grounds.

I'll also post my photos of the converter and wiring diagram next time I run to my house.

[zero]

Usually the converters have a ground bus-bar inside the converter. If so, you can run just one good guality "ground" from the converter bus-bar to the truck frame. Then all other grounds can be hooked up to that bus-bar, if wanted. The only exception would be something with very high amp draw, e.g. a DC to AC inverter. That would need the negative hooked directly to the battery.

[MontanaChinook]

Ok, thank you. I think it will be easier to wire it all new, instead of figuring out what the old wiring does, and just reconnecting what Chinook did.

I'm going to study the wiring diagram a little better and see what the electrician did with the circuit breakers, and see how much of this I can figure out.

I see on the diagram that I've got a DC disconnect which is optional. What's the idea behind this? What is it?

[MontanaChinook]

And let's just keep this over here since you're the only one from the chinook group answering most questions. It's way more convenient posting here than using email format.

[zero]

I see on the diagram that I've got a DC disconnect which is optional. What's the idea behind this? What is it?

The DC disconnect allows you to disconnect the batteries from all the appliances and lights.

[MontanaChinook]

Yahoo email is NOT working well today...ending up in outbox and adding weird code to apostrophes....

So I'm taking that over here.

RE wire size:

I was just going by your first response on the yahoo group that said "you can't wire too big. Only too small".

So I thought I was ok.

If, by using 12 gauge, I'm risking fire, and if, by using 10 gauge for the battery, same thing, it's not too late to take the wire back. I can go 14 gauge for appliances and 12 for the battery. Let me know...

[MontanaChinook]

Why would I want to disconnect them from the battery?

[Derek up North]

Wire sizing is all 'screwy'. The smaller the number, the BIGGER the wire. So #12 is BIGGER than #14.

Below is a link to the Factory wiring from Winnebago. You'll see that most of the wiring is #14 (a couple of #12) with the exception of #10 in the battery wiring.

Your #12 should be fine. Just make sure all the circuits are protected with fuses.

http://www.winnebagoind.com/diagram/1991/088594.pdf

[zero]

Why would I want to disconnect them from the battery?

Suppose you smelled smoke somewhere and wanted to make sure all the battery power was shut off? Suppose you wanted to rip out some wires and do some work? I can think of plenty of reasons to want the battery disconnected from the system. Having a switch is a convenient way to do it. Every RV I have has a some-sort of battery disconnect switch built into it. So did the original Basler converter that you removed.

[MontanaChinook]

Ok. I thought maybe one of those circuit breakers would do that. ?

Or is that what the guy installed one of them for? To wire to the dc disconnect. Maybe...

You'll have to bear with me. I'm not dumb, but I don't know the terminology (no idea what a bus is), and don't have much experience. I did figure out how the wire gauge sizes work, though.

So, how is having a dc disconnect different from just flipping the breaker between the battery and power center? I see a place to put a wire that says "dc disconnect", but there's nothing there for me to push or flip. So how does it work??

[zero]

Yahoo email is NOT working well today...ending up in outbox and adding weird code to apostrophes....

So I'm taking that over here.

RE wire size:

I was just going by your first response on the yahoo group that said "you can't wire too big. Only too small".

So I thought I was ok.

If, by using 12 gauge, I'm risking fire, and if, by using 10 gauge for the battery, same thing, it's not too late to take the wire back. I can go 14 gauge for appliances and 12 for the battery. Let me know...

I'll try to restate again. Getting a little redundant doing this on two separate forums.

Fuse size is determined by wire size. The fuse must be small enough that it will melt before the wire does. If a circuit breaker it must break open the circuit before the wire melts.

Wire size is determined by the highest max amp load AND how long that wire is. If a wire is too small, the wire heats up and you get a voltage drop from one end to the other. With a 12 volt system, 5% is usually the most drop you want to allow.

So when you determine what wire sizes to use - the first priority is the voltage drop. Once you know what size wire is needed, you then install the fuse or circuit breaker to match the wire-size and/or ampacity rating.

For protection only - a 16 gauge copper wire needs a 15 amp fuse. A 14 gauge wire needs a 20 amp fuse. A 10 gauge wire needs a 30 amp fuse, A #2 battery cable needs a 100 amp fuse.

Here is one example. Let's say you have a circuit that draws a max of 6 amps, like a water pump or a DC compressor refrigerator.

If the wire-run is only 5 feet long you could use 18 gauge wire and a 10 amp fuse.

If 20 feet long you'd need 16 gauge wire and a 15 amp fuse.

If 60 feet long you'd need 12 gauge wire and a 20 amp fuse.

If 100 feet long you'd need 10 gauge wire and a 30 amp fuse.

[MontanaChinook]

Yeah I'm sticking to this forum for this. Much easier.

then should I ignore your first statement of "you can't wire too big, only too small"? Because a light with a low amp draw, if there's a surge, will not blow the fuse or melt the wire, and so may itself melt and burn. Right?

So using 12 gauge for an led light with at most 5-10 feet of length is too heavy a gauge. Yes? No?

Thanks Derek, it would be nice to not have to exchange the wire, but if the above is a concern, I probably should...

[zero]

Ok. I thought maybe one of those circuit breakers would do that. ?

Or is that what the guy installed one of them for? To wire to the dc disconnect. Maybe...

You'll have to bear with me. I'm not dumb, but I don't know the terminology (no idea what a bus is), and don't have much experience. I did figure out how the wire gauge sizes work, though.

So, how is having a dc disconnect different from just flipping the breaker between the battery and power center? I see a place to put a wire that says "dc disconnect", but there's nothing there for me to push or flip. So how does it work??

I have no idea what somebody may of wired into your RV. Usually the built-in toggle/flip style circuit breakers in a converter power-center only control the AC power and have nothing to do with DC. In fact, the flip-style circuit breakers are kind of rare. Very common in the solar industry but not very common otherwise. Square D type QO are the only ones I know of that are are common and dual rated for DC and AC. Any switch or breaker that works on 12 volts DC has to be a lot more rugged then one built for just 120 volts AC. Again though, I"m not sure what you have.

[zero]

Yeah I'm sticking to this forum for this. Much easier.

then should I ignore your first statement of "you can't wire too big, only too small"? Because a light with a low amp draw, if there's a surge, will not blow the fuse or melt the wire, and so may itself melt and burn. Right?

So using 12 gauge for an led light with at most 5-10 feet of length is too heavy a gauge. Yes? No?

Thanks Derek, it would be nice to not have to exchange the wire, but if the above is a concern, I probably should...

Sometimes due to a long wire run a low draw appliance has to be wired with big wire and a big fuse. That's okay as long as the light or appliance is mounted in some-sort of fire-proof box or container. All depends on what you have. In household wiring, all circuit hookups to appliances are in some sort of enclosures. Not always the case in RV and some RVs burn up. And yes, so do some houses but usually the houses.

[zero]

Sometimes due to a long wire run a low draw appliance has to be wired with big wire and a big fuse. That's okay as long as the light or appliance is mounted in some-sort of fire-proof box or container. All depends on what you have. In household wiring, all circuit hookups to appliances are in some sort of enclosures. Not always the case in RV and some RVs burn up. And yes, so do some houses but usually the houses.

I should of qualified that statement. All household hookups that are "hard-wired" use enclosures. Obviously you can have a 20 amp outlet and plug a 1 amp appliance into it with an 20 gauge wire just laying on the carpet. that's the sort of thing that can cause a fire since a 20 gauge wire is apt to melt before a 20 amp breaker trips. It's also why there are all kinds of new problem-sensing breakers being used. Ground fault, arc fault, etc.

[MontanaChinook]

Ok, well, I appreciate all your help. I think I'm going to go elsewhere or find someone locally from here.

I think you just know too much, and me too little, for me to learn much from you when it gets to specific stuff like this. I feel like we're again getting into stuff where I'm getting a ton of information, but can't seem to find the answers to my questions in that info. I'm just not on the right level.

Again I think it's an issue with my knowledge level, not an issue with your help.

Thanks! I'll let you know how it goes in my project thread.

[Maineah]

Ok, thank you. I think it will be easier to wire it all new, instead of figuring out what the old wiring does, and just reconnecting what Chinook did.

I'm going to study the wiring diagram a little better and see what the electrician did with the circuit breakers, and see how much of this I can figure out.

I see on the diagram that I've got a DC disconnect which is optional. What's the idea behind this? What is it?

IMG_1180.JPG IMG_1209.JPG

What is the converter it's not the original. The breakers are AC breakers wired to your power cord the 30 amp is the main it kills all power from the 30 amp power cord the other two are for outlets in the camper usually there are a 30, 20 and 15 amp, 10 gauge 30 amp feed 20 amp #12 wire AC and 15 amp outlets #14 wire. I the case of your converter one of the 15's may provide power to the converter it's self. The converter is very nice and wired properly as far as the 120 volt ac stuff. There is a buss bar that looks as if it by passes what may have been a battery disconnect (marked optional) it most likely feeds the ATC fuse bank the black wires on the other side are 12 volt loads there must be hookups on the other side for your 12 loads lights ,heater etc.The large lugs above the empty fuse bank are all 12 volt battery stuff both battery and converter lugs and it looks as if the converter is factory wired so all you need there is battery + and - You should have a frame ground wire connected to the ground terminal buss bar in the 120 volt side on the converter box it is very important to have a good frame ground there it looks as if it does check the heavy bare wire and see where it goes.

[MontanaChinook]

Thanks.

Converter is a brand new progressive dynamics. I had an electrician wire the 120 stuff, which is why it looks correct

I'm just trying to figure out the 12v side. I understand, basically, needing power and ground. Power is coming from those twelve circuits, wires coming out the back.

I'm not sure if I wire all the grounds to the converter and then ground the converter, or run grounds for the appliances myself, outside of the converter.

Anyway I'll look closer at the wiring diagram and instructions, and google some terms I don't understand, and see what I can figure out. There's clearly something major with this thing that I'm just not quite grasping, and having it explained (sort of) with more terms I don't understand isn't doing much for me.

Clearly this is beyond my current abilities but I think I can get there if I can find someone, hopefully in person, to look at it and explain things.

The issue seems to be that unless you already know how wire stuff, people can't teach you how to wire stuff...I guess I need to buy a "wiring 101" book or something. Every time I think maybe I've figured some basic thing out that I can build from and ask if I'm right, I get overloaded and am either wrong in what I figured out or I don't hear from people whether I was right or not...

So I'm going to try to find a different method of learning wiring, I guess. I seem to know too little for people to be able to communicate in a way I understand and can build from. I need absolute basics first, then build on that. So far I have no solid ground to build from. Seems all my assumptions, when I think maybe I've got a basic down, are wrong.

[zero]

I'm not sure if I wire all the grounds to the converter and then ground the converter, or run grounds for the appliances myself, outside of the converter.

I'll stick to answering one question to keep things simpler. But . . "ground" and "DC negative" are not always the same thing and I think you are confusing the two.

For purposes of wiring an RV, the vehicle chassis is considered the "ground" although it is not really grounded.

All the appliances and lights that run on DC get hooked via two wires. One is 12 volts positive and one is 12 volts negative.

There IS a difference between the the two but at your request, I don't want to complicate things further.

The converter-power center probably has a single large lug made to accommodate a fairly large solid copper ground wire and that is what gets hooked to the truck frame.

The converter/power-center has a centralized location where every negative wire from every circuit gets attached to. So, in brief only the converter gets hooked to the frame via a main ground connection. All the appliances and light circuits get hooked to the converter where that centralized negative hook-up area is.

Read the book. And yes, your are correct - I don't know how to break it down to anything simpler.

[MontanaChinook]

Thank you. Sorry got frustrated there but I think I'm just too far behind to really be doing this sort of job. Of course I'm still going to do it.. But it's going to take a while. But everyone who tried to describe it...kind of loses me. I need to start from absolute basics and build from there, but I understand people here aren't on that level. You're all trying to tell me the way of wiring an RV, when I guess what I really need is electronics 101.

Ok. There is absolutely a solid, bare wire running down through the floor from the converter, and I will trace it to make sure there's a good connection to the frame.

And I need to be looking for one place on back of the power center to attach all negative wires to. I'll see what I can find as to the difference between negative and ground, because you are correct, I did not know there was a difference.

I do appreciate the help.

[Derek up North]

A ground (earth) is a ground. It just so happens that all modern cars (that I know of) have a 'negative ground'.

[zero]

Thank you. Sorry got frustrated there but I think I'm just too far behind to really be doing this sort of job. Of course I'm still going to do it.. But it's going to take a while.

If you look at the diagram you posted for your Progressive Dynamics power-center - it has just about all the connections pretty clearly marked. Note that it has a big connector for battery negative on top left-area. They are not calling it "ground." What I cannot see in the diagram is what sort of hook up is used where there are 12 separate DC circuits available, each with a separate fuse. I suspect there are small lugs or screws in back to facilitate hooking both negative and positive from each circuit.

The chassis ground, .e.g. the solid copper wire that hooks from the truck frame to the metal case of your converter is probably separate. It is usually a bar with a hole in it with a screw that tighens down the ground wire. Your install book should show it's location but it ought to be obvious.

That converter looks like it's very well designed and makes wiring an RV about as easy as it can get. But yes, you still need to know basic principals.

Is it a model PD4000 Mighty Mini?

[MontanaChinook]

It is a mighty mini. I think that's a 4045, though, but I'm not positive.

The 12 DC circuits each have a wire coming out the back, where I've been assuming I hook the + wire. I'll look again today to see if there is a place for the - .

No, they don't say ground, they say negative, but when you're someone who thinks ground and negative are synonyms, why would that challenge my world view?

But I'm beginning to understand.

[MontanaChinook]

Glad I'm not the only one who was confused..

http://www.fiberglassrv.com/forums/f55/progressive-dynamics-pd4045-42372.html

Looks like I need to buy something to connect the negative wires to, or I can just go the frame with them.

[zero]

It is a mighty mini. I think that's a 4045, though, but I'm not positive.

The 12 DC circuits each have a wire coming out the back, where I've been assuming I hook the + wire. I'll look again today to see if there is a place for the - .

No, they don't say ground, they say negative, but when you're someone who thinks ground and negative are synonyms, why would that challenge my world view?

But I'm beginning to understand.

In AC wiring - neutral and ground are joined together at some point. In DC systems, battery negative and ground are also joined together at some point.

Thus the reason why they terms get intermixed.

In your RV, you've got AC and DC wiring all mixed together which can be even more confusing. AC neutral, DC negative, and chassis ground can all be bonded together at some point.

When it comes to auto/truck/RV wiring- assuming the vehicle has a metal frame- often the metal frame is used as one "wire" to carry the negative current. It's sort of a way to "cheat" and save costs on wiring. Technically cars, trucks, and RVs have no ground since they sit on rubber tires and are insulated from the "ground" which refers to the planet earth. On the other hand, houses wired for AC have a true connection to earth's ground. Usually with ground rods driven into the ground.

And just so someone doesn't complain about any sweeping statements here - some cars and trucks have wooden frames. Also not all cars and trucks are negative "ground." Some are positive ground and some are both or none. I have a 1964 John Deere tractor that is split down the middle. Half the tractor is negative ground, half is positive ground, and the charging system has no ground (totally isolated).

[zero]

Glad I'm not the only one who was confused..

http://www.fiberglassrv.com/forums/f55/progressive-dynamics-pd4045-42372.html

Looks like I need to buy something to connect the negative wires to, or I can just go the frame with them.

I doubt that. A electrical panel made for 120 volts AC and 12 volts DC will have at least four main connection areas and often five.

#1 is for AC "hot"

#2 is for AC "neutral"

#2 is for battery "positive"

#4 is for chassis ground. This is used for AC ground and DC "negative."

#5 is for one main ground wire from the metal case to the truck frame. #4 and #5 are joined together. #4 is for hooking small wires to, and #5 if there is for one large wire to go to the truck frame.

Your box comes with one ground bus-bar as standard equipment and also shows and optional 2nd ground bar mounted top-right in the diagram. They call it the "optional chassis ground PD812375."

[zero]

.

#2 is for AC "neutral"

#2 is for battery "positive"

Obviously a "typo" or "keyboard-o" on my part. #2 is AC neutral and #3 is for battery positive. I made up those number and they do not refer to numbers on your diagram.

[zero]

Here's a Progressive Dynamics Mini diagram showing the standard ground bus bar for all AC grounds and DC negative connections from appliances Also shows the 2nd optional one that can be added if wanted.

[MontanaChinook]

Ok, thanks!

That is not my converter, so I'll check mine to see if I have a bar like that.

The second page of the link I posted - quotes a response from a PD representative instructing the guy to add something for grounding. But I don't know what his exact question was to PD...

[zero]

Ok, thanks!

That is not my converter, so I'll check mine to see if I have a bar like that.

The second page of the link I posted - quotes a response from a PD representative instructing the guy to add something for grounding. But I don't know what his exact question was to PD...

Progressive Dynamics sells stand-alone power converters, and combo converter/.power-centers. The "Mini" is a combo and should not need any extra bus bars added.

If the guy you mention only had a stand-alone converter, and not a combo-power-center - then yeah, he'd need some extra bus bars, fuse panels, etc.

[zero]

Ok, thanks!

That is not my converter, so I'll check mine to see if I have a bar like that.

The second page of the link I posted - quotes a response from a PD representative instructing the guy to add something for grounding. But I don't know what his exact question was to PD...

I still don't know what model you have. Here is their smaller PD4000 Mini. It has a ground bus-bar that has seven connectors. Each one can probably hold two wires. Thus 14 wires in all.

[WME]

Back when you were discussing wire size "J" listed appropriate wire and fuse sizes. Please remember that a fuse is to protect the appliance from itself as well as to protect the wiring. Just because you are using 10 gauge wire somewhere doesn't mean you need to use a 30 amp fuse. A 5 amp fuse may be more appropriate for your load.

Under fusing a large wire is safe, over fusing a small wire is NOT safe.